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Wood Primer

Wood is naturally a porous material so it is important that the surface is sealed to ensure that solvents within subsequent coats are not absorbed too readily which will cause premature drying and potential failure of subsequent paint layers. A first coat of primer will also consolidate loose fibres on the wood’s surface which will enable sanding to a smooth finish before applying finishing coats.

There are a range of wood primers available, all with different qualities, and the choice can be confusing.

Water Based Wood Primers

Water based primers are often acrylic based, are more pleasant to use than solvent based alternatives and can perform well if used correctly. The advantages of water based primers are quick drying, good opacity (covering power), low VOC content and brushes can be cleaned with water.

Water based paints can not be used where the risk of rain is imminent and another disadvantage is that these kinds of paint can clog up abrasive paper which makes it difficult to get a really smooth finish. Some water-borne stains can also bleed through the surface of acrylic paints.

quick drying acrylic primer/undercoat

Quick Drying Primer/Undercoat is a general purpose acrylic wood primer and combined undercoat suitable for interior use in a range surfaces including softwoods, hardwoods and building boards including plywood.

MDF Primer

MDF Primer is an acrylic primer formulated for use on MDF which is typically more porous than regular softwood. It is quick drying and can be used as an undercoat.

Premium acrylic primer

Rubol Primer Plus is a premium quality acrylic primer/undercoat for use on exterior timber. You can use regular water based primer outdoors but it’s worth spending a little extra to get the best result.

Oil Based Wood Primers

Solvent or alkyd based primers (commonly known as oil based primers) have been used traditionally to prime new wood. The advantages are that they dry to a hard finish that can be rubbed down to provide a smooth surface.

Oil based wood primer
Oil based primers are compatible with traditional undercoat and gloss paint and will contribute to achieving a high sheen finish. The disadvantages are slow drying times and they can be messy and unpleasant to use.

Aluminium wood primer

Aluminium wood primer is an oil based primer with a high aluminium pigment content. Used for some hard woods which contain high amounts of resin which discolors traditional wood primer. Can also be used for very knotty timber where the use of patent knotting isn’t practical.

One problem with aluminium wood primer is that the bulk of the pigment will settle in the bottom of the can if left for even moderate periods of time so it’s essential that it is thoroughly stirred before use.

There are some other kinds of specialised wood primers but this covers the basics. The general rule with all types of primer is that thorough preparation will always yield good results and when selecting a primer for the job you should always use the best quality primer you can afford.

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Comments

  1. I would like some advice please. I’ve sanded back some wood beading and paneling in a bedroom in parts back to the bare wood. I’ve cleaned it all down. I used a dulux wood primer and undercoat (all in one) but as soon as I put it on I noticed it turning a creamy colour particularly on the areas where I’ve exposed the bare wood whilst sanding. I took advice from some guys at B&Q who have told me to use a higher acrylic based all in one primer and undercoat. They suggested valspar. They told me to lightly sand the area down before applying a coat of this new stuff, then to let it dry before lightly sanding down again and applying a 2nd coat. Well so far I’ve got to applying the first coat of the new valspar product and I can still see the creamy yellow tinge starting to appear. Please tell me what to do to sort this out as ultimately I am looking to paint them in an eggshell water based paint in a light grey colour but I’m afraid the top colour will be tinged with the staining that’s coming through. Do I persevere and put a 2nd coat on or am I wasting my time.
    Any advice will be greatly appreciated.

    • Yes, you will be wasting your time adding another coat. The people at B&Q ought to refrain from giving advice on subjects they know nothing about.

      The wood has a waterborne stain and any subsequent coats of water based paints will dissolve it and allow it migrate through to the surface. A coat of oil-based paint will stop this happening; simple white undercoat will do the trick and then you can continue as before. There are some spirit base ‘stain-blocking paints’ that do the same thing but you’ll have to judge for yourself whether it’s worth paying the extra.

      However, to avoid any compatibility problems, you’ll need to let the undercoat fully cure before over-painting with a water based finish (a full week, if you can wait that long?). Less time if you use a spirit based product but still wait as long as you can.

    • Many thanks for your advice. If I were to put the grey top coat of paint over the yellowing undercoat as it is, will it affect the grey coloured top coat?

    • The staining will continue whenever you apply a water based paint, only an oil based paint will stop it. When you have applied a coat of oil based paint this will act as a barrier, so then you can go back to the original water based paint it should be OK.

  2. The fascias to my porch have been repaired with new external plywood. I want to paint them to match the rest of the porch, which has an oil-based gloss finish. Should I use an oil-based primer or would water-based be OK?

    • You can use a water based primer but to achieve the same finish as the rest of the porch you’ll need to complete the work with an oil based undercoat before glossing. I say this because a lot of water based primers can also be used as an undercoat but an oil based gloss directly on top will often dry ‘flat’ (without a gloss) and need more coats than usual.

    • So if I used an oil based primer could I avoid using an undercoat or would I still need 3 coats?

    • Not really, no. It’s very rare you’d get away with doing that. And because plywood, especially, is very absorbent I would say absolutely no chance on this occasion.

  3. I just bought a bare wood backdoor want to use the dulux weather shield system and go with a satin finish, the brochure states that bare wood needs 2 coats of exterior preservative primer so have done that but can’t work out now if I need to use undercoat before using the quick dry exterior satin the booklet says no need but the cans say 2 coats of undercoat any ideas?

    • No, the exterior satin can be used coat-on-coat so just apply two or more coats to get the desired finish. In other words, the first coat is the undercoat.

  4. Help please , I am redecorating a hall and stairwell which has a ceiling height of over four meters. The walls are covered in wallpaper which I intend to paint over. The idea is to save time and money. I understand I should prepare the walls by priming the existing wallpaper with an oil based primer and then give a light sanding prior to applying paint. Is this the best way to go about it and if so please advise which primer would be best for the job.

    • In principal you are correct but since it is such a large area I think it is wise to take a few precautions.

      Firstly, painting over an existing wall-covering is always a risk since you never know how well it is stuck to the wall, you only find out once you paint it.

      Also, using an oil based primer will prevent any stains migrating through to the final finish. And, because oil based paints dry harder, this will make it easier to sand to smooth finish. But, painting such a large area is going to create a lot of odour that’s going to hang around for quite a while and you don’t want to go through that unless you really have to. It would also be quite annoying if you later discovered the paper wasn’t stuck so well and you had to strip it afterwards?

      What I would do is paint maybe the largest wall first with a coat of regular emulsion and then see the next day what the result is. If it is satisfactory you could go ahead and complete the job this way. It’s definitely worth a try. It may be that can get away with just spot priming a few stains here and there, or you may not even have to do this at all.

      If you do have to resort to priming the whole area a basic white undercoat will do the job just fine. You can buy special primers but they do much the same thing and cost a lot more money. Also, ensure there is plenty of ventilation and don’t try and complete the job in one go – keep going outside to ensure you are getting fresh air too.

  5. Can I use an oil based woodstain on top of a water based stain externally?

    • You could be I wouldn’t recommend it. If you do, try a small area first just to make sure there isn’t an adverse reaction.

  6. I have sanded down to bare wood the front door of my Victorian house .
    I want to know how to get the best shiniest finish .
    Should I use aluminium primer with oil based undercoat and gloss ?
    And if spray painting with a top coat of oil based gloss , do I need to thin the gloss paint and if yes would that be with white spirit ?

    • If you want a high gloss finish then an oil based system of primer, undercoat and gloss will give the best results. I wouldn’t use an aluminium wood primer unless really necessary, for instance if the door is teak or mahogany or some other wood with a lot of knots in in it?

      The ideal system is one coat of wood primer, 2 coats of under coat and 2 coats of gloss. The more coats of gloss, the deeper the finish. Also, I wouldn’t contemplate using a spray application unless you have prior experience; your question about how to thin gloss suggests you don’t have any (yes, it’s white spirit btw).

      It’s also worth pointing out that the gloss coat will only ever be as good as what is underneath it, a lot of people skimp on preparation and then wonder why the end result isn’t as good as they thought it would be. So your undercoat needs to be perfect and rubbed down to a smooth finish, and all traces of dust removed, before applying any gloss.

  7. I recently prep’ed a hard wood door and frame which until now was varnished. Burnt all the old varnish off, sanded, cleaned ready to go. Bought what I think is a half decent Roseal white water based primer. Trouble is after one coat the white is discolouring. Bloomin annoying as this primer is said to stop that /be a sealer etc. Can I now rub this down and go with an aluminium primer. Would the two be happy to mix?! And would that potentially cure the problem and stop the bleed through?

    • What’s happening is that there was a water based stain already present and it’s become soluble with the use of a water based primer. A coat of oil based undercoat will stop the stain coming through and provide a sound base for subsequent coats of oil based finish.

      If you opt for a water based finish you are going to experience this problem at every stage.

    • So just to check, the oil based primer should adhere to this thin coat of water based primer I’ve put on as long as I give it a good rub down.

    • I would ensure you have a good coverage of the primer you’ve already used even if that means applying another coat. Then I would go straight to an oil based undercoat – not primer.

      An oil based primer probably would adhere OK but primers are formulated primarily to seal the wood rather than to stick to an existing coating. Hope that makes sense?

  8. Hello, I have been advised by our joiner to use aluminium primer to cover a wooden porch that looks mahogany and was varnished, though is now badly weathered. We want to have a satin finish eventually. Should I use a satin/water based primer over the aluminium before I paint the top coat in dulux weather shield satin? Thanks

    • You shouldn’t use aluminium wood primer unless you are using a traditional oil based undercoat and gloss system. If you want to finish with Weathershield satin then you should use the Weathersield primer and undercoat instead.
      Ensure that any remaining varnish is completely removed before doing anything though. And, if the wood is weathered (usually grey or silver with cracks along the surface) any paint system will fail prematurely – so you’ll need to repaint every couple of years at least. The water-based Weathershield system tends to be more durable (because it stays flexible for longer) and will probably be your best bet in this instance.

  9. We have 18 oak window frames in a period house that were installed circa 25 years ago. Most of them were treated from the start externally with Sikkens HLS and Cetol Filter 7 (light oak) and have been retreated occasionally since, using the same products. Several of the sills now have fissures in them along the grain where the oak has weathered, and there is some rot in the joints, underneath the casements. The uprights don’t show any rot, but mould has taken hold where the stain has flaked off. As I am now having to replace the double-glazing units, many of which have blown, it’s time for a major overhaul. I have sanded down the frames to remove the old stain, and as much of the grey wood as possible, but the unevenness of the surface makes it impossible to remove all the rot by sanding down, especially from the fissures in the sills, some of which are 2-3mm deep. My plan is to use a fungicidal wash followed by a wood preservative, together with a wet rot wood hardener on the sills, and then to recoat with Sikkens as before. I’m filling the rot under the casements with two-pack filler, but I’m not planning to fill the fissures in the sills (a previous attempt to use filler on an exposed area of one frame, to fill a deep crack caused by a shake in the timber, was a dismal failure, as the filler came loose within a year or so. Also, the two-pack fillers all seem to be pale in colour, so the filled areas show up badly through the wood stain). My question is, am I wasting my time trying to re-stain these old frames? Do I need to fill all the fissures in the sills before restaining, and if so, can you recommend a filler that will do the job (ideally one that is darker in colour)? And if restaining is a lost cause on these old, weathered frames, can you suggest an alternative treatment I could use?

    • Once hardwood becomes denatured, characterised by the greying and cracking you describe, there isn’t much you can do that’s going to stand the test of time. It’s more a case of managed decline than an an all-out repair.

      The treatment you propose is about the best you can do but you’ll have to accept this is going to something you’ll need to repeat every couple of years or so.

      All wood fillers will fail eventually when used externally although Toupret tend to be one the better brands. The problem with getting the final colour to match is a common one although you could, maybe, opt for an opaque stain rather than a semi-transparent one? The perform just as well as you should be able to get a finish that’s someway acceptable. The only other option is to revert to standard paint.

  10. I’m looking to paint over hardwood (mahogany I think) patio doors and window frames, both inside and out. We want a white (or near white) satin/matt colour for the interior surfaces, and a dark grey satin/matt for the exterior. I’ve previously treated the exterior surfaces with Sikkens HLS Cetol stain. Interior surfaces have a smooth feel – so I’m wondering if there could be some sort of waxy top coat. The exterior stain has tended to flake off – could this be because of a waxy top coat?

    What sort of prepation and treatement do you recommend for interior and exterior? Could I go for a water-based treatment for the inside surfaces and an oil-based one for the (very exposed) outside? I’m guessing an oil-based solution is needed for the outside, using an Aluminium based primer or one of the Zinsser products. I don’t mind buying the more expersive products to get the job done right.

    • Water based finishes can prove to be more durable for exterior woodwork because they remain flexible for a longer period of time; traditional gloss gives a better finish but becomes brittle leading to early failure. Dulux Weathershield gloss (if you want a an oil based finish) is better though since it is formulated to accommodate the natural movement in timber. Sikkens also do a range of opaque finishes called Rubbol, both satin and gloss, that perform equally well.

      I wouldn’t worry too much about using the same system on both sides of the doors. The only issues you’ll encounter are a possible loss of adhesion, as you mention above, and the likelihood of the stain bleeding through the new painted finish and causing unsightly staining. Aluminium wood primer will solve this problem, as will most acrylic, water or spirit based primers (like the Zinsser products you are aware of).

      Preparation is, of course key, and it’s essential you remove any loose coatings to start with as well as ensuring the surfaces are fully cleaned with a solution of sugar soap and then rinsed with clean, warm water.

    • Thanks a lot for the reply, that’s very helpful.

      I’m still a bit unsure about the preparation. The doors and windows were installed by our predecessors, and the company that installed them has gone out of business – so I don’t know what the original treatment was. Although it’s weathered away in a few places on the outside it still provides a glossy smooth surface on the inside – that looks and fees a bit waxy, but could be a varnish for all I know.

      I’ve discovered that there are wax removers such as colron and grax-it, liquid sandpaper, nitromors, amongst other products – and I’m still none the wiser as to which would be suitable. It’s obviously hard for you to say what the treatment might be without seeing it, but is there some sort of treatment that will deal with all eventualities? Would sugar soap suffice when it comes to providing the key I need for the primer, given the uncertainty about the nature of the existing treatment?

    • OK, I think the mention of you using Sikkens is the source of some confusion. If you are unsure of the original finish it’s best to proceed with extreme caution.

      It may be worth wiping down the surface with a cloth soaked in white spirit to see if this removes some of the waxy residue? If it doesn’t try again with methylated spirit. It’s almost certain one or the other will do the trick.

      Give the surface a light rub down with a fine abrasive paper and then wash off with the sugar soap and rinse with warm water. This should provide an adequate key.

      Since there is always the chance of an adverse reaction with a different kind of paint I think it’s best if you do a trial area first with your chosen system. My feeling, with the benefit of added information, is that the all Zinsser primer may be your best option as a base for both internal and external surface. But, as you rightly point out, it’s difficult to say for sure but at least doing a trial area eliminates the prospect of it being a total disaster. If, after a few days, the paint doesn’t easily scratch off you should be OK.

  11. We have built a detached garage, it is of concrete block construction clad in rough(ish) timber weather board. Without researching it we first used two coats of water based primer / undercoat and then two coats of Dulux weathersheid water based top coat.

    This was completed about a year ago. Since then, we have reached the conclusion that a lighter, off white colour would look better than the rather yellowy cream it has become and also there are signs of the timber resin seeping through the finish.

    We don’t have the resources to sand the entire building back and go through the knotting solution etc, can we just go over as is with a couple of coats of oil based timber paint, or re-prime with aluminium primer and then top coat in water based or oil based top coat?

    • You shouldn’t use knotting solution with water based coatings as it isn’t compatible, the same goes with aluminium wood primer.

      If the staining is really bad you could use a water based stain block over these areas and then repaint with the colour of your choice.

  12. I have painted an old victorian front door with a Farrow and Ball unercoat and exterior eggshell after having lightly sanded said door. After a few days, tiny bubbles have appeared in various places. I started the whole process again of sanding back to old paint, use FB undercoats and topcoat again. After a few days, bubbles have appeared again. Not sure what to do. Have done some research online and seen this has happened before. What is the solution? Using an oil undercoat with water based FB or ditch the wretched FB paint altogether and go for an all oil based solution?

    • Hard to give a definitive answer but it could be something simple like applying the second coat before the first has fully cured?

      It’s also possible there is some surface contamination from the previous finish. You say you lightly sanded it down but, assuming it was a regular gloss finish, it would need better preparation than this.

      Using water based finishes over previously oil based finishes can often be problematic. If you want to still use the same paint it might be worth experimenting with a solution on a trial area?

      Take an area that’s badly affected and sand down lightly so you have a smooth surface again. Wash it thoroughly with a solution of sugar soap and rinse so all residue has been removed.

      Apply a regular oil-based undercoat to this area only and leave at least 3 days. Assuming there are no bubbles give this a light rub down and apply a coat of the F & B undercoat then leave a full day. Again, if there are no problems, finish with a coat of F & B eggshell. If there are still no problems this will be your solution.

      Alternatively, if the above doesn’t work, you could revert to a standard oil based system and just colour match the F & B finish you wanted.

  13. I do a lot of artwork on plywood panels. Normally i use a quickdry primer/undercoat then apply an acrylic gesso before i paint on top. However, i have just primed a panel with oil based primer (my fault,poured it before reading), and am concerned an acrylic based paint will peel. Best to sand it back? Or can i leave to cure and then put an acrylic gesso on the top?

    • I’m not familiar with geso, in any form, but when applying water based paints over an oil based surface it’s always best to ensure the previous coating has fully cured first. In the case of an oil based primer this can be at least 2 – 3 weeks. Abrading the surface with fine sandpaper will also help ensure the acrylic bonds properly.

  14. New pine bannister and handrail, very knotty. I have knotting solution and a water based eggshell topcoat. What primer should I be using on the bare wood?

    • I would suggest an acrylic/water based primer. If doing so you don’t need to use knotting solution, it can react with water based finishes and, also, you don’t get the same degree of staining you would with an oil based finish.

      However, if the knotting is severe I suggest you use knotting as planned, prime with an oil based primer and then one coat of oil based undercoat. Leave for 2-3 weeks for this to fully cure and then use the water based eggshell as planned. You may need extra coats to get the desired result though, in which case use a regular oil based eggshell or satin finish instead.

  15. I have stripped external shutters and sanded and painted with water based primer. Problem being rust showing where they have been pinned to keep slats in place. It would not be practical to rein all slats. Will an oil based primer cure this?

    • Yes, specifically a metal primer containing zinc should do the trick.

  16. Adrian asks:
    I have a new wooden gate, untreated. Before painting with Farrow and Ball primer and eggshell water- based paint I want to use a wood preservative. I have had experience of using a clear preservative, before painting as above,with bad results where the preservative seemed to form a “waxy” type of finish when the paint was applied.
    Are there preservatives specifically designed to go under water based paints?

    • You could use something like Dulux Weathershield Exterior Preservative Primer that’s a bit of half primer, half preservative? But, generally speaking, you are always going to have problems.

      Ideally if you are going to use a wood preserver it’s a good idea to give the wood a good soaking and then leave it sometime before painting. This gives the preservative plenty of time to dry out fully and will eliminate the problem of surface contamination to a great degree.

      It’s hard to say how long this should be though because it depends a lot on the type and quality of the timber and how exposed it will be to the elements. I’m thinking in terms of weeks though rather than hours or days if that helps?

  17. Hi I’m looking to seal the inside of a summer house. I’m using Creocote. The smell is horrendous and the warning for health aren’t great. Is this a good product to use or not. Also will the smell disappear??

    • There are loads of water based alternatives available that have much less odour. You will need more coats for a decent finish and to retreat more often, maybe every couple of years, though.

      Ronseal Fencelife and Cuprinol Ducksback are popular although there are plenty of alternatives.

  18. One more thing I forgot to mention, I haven’t stripped the ply simply because it’s very difficult to get off and I figure if it wants to stay on even when attacked by a heat gun then let it.

    • Fair enough, but ensure it’s sealed all-round as mentioned in my previous answer.

  19. I recently built a Tardis. It is made mostly of softwood from b&q and plywood for the roof and panels. There’s also lots of exterior wood filler covering countersunk screw holes.
    I painted it with two coats of Dulux weathershield White undercoat and three layers of dulux weathershield Oxford blue satin, all water based, I then gave it two coats of Rustins clear exterior varnish.
    First of all the colour quickly became white speckled but after a few days of heavy rain, bubbles/ blisters appeared in four different places, I scalpelled them off to find completely bare wood (all layers had lifted). I quickly dismantled her and took her back in the garage. I’ve now stripped her down to bare wood completely with a heat gun. It has taken a long time but I don’t mind. The thing is when I paint it again it has got to be properly. I can’t keep taking it apart and stripping it every time there’s a problem. I did some research and found out about knotting, there are knots in places but not below any of the blisters that appeared, I’ve got some knotting solution but it says not to use beneath water based stuff. Also I didn’t use primer just ordinary undercoat. And I’ve read about cleaning with white spirit before painting to remove contaminants.
    Being that I’m starting from bare wood again can you tell me where to start and finish. I really have to do it properly this time.

    • The exterior varnish was likely to be the problem since it would stop any trapped moisture escaping. I would have used an exterior gloss, such as weathershield, rather than satin.

      You should also have used a primer. And, because you have plywood panels, it’s wood also be a good idea to ensure the inward facing surfaces are also painted, wherever possible. Plywood is notoriously difficult to seal from the weather and you need to ensure that every possible surface and edge is properly sealed – even if not visible.

  20. We have just moved into a Victorian home with a 6 yrs old softwood conservatory which now needs redecorating externally. It was originally finished with Witham Woco water based joinery topcoat which has a slight sheen but this is no longer available from the manufactuer. Can you recommend a preparation and finishing system?
    Also, the rest of the sash windows are oil based gloss in fair condition, would you advise sticking to oil based although water based would be easier and quicker to apply?

    • There are a few satin finish coatings available and preparation should be straight forward. Wash down the existing coating and lightly abrade to remove any rough edges (much less than you would for regular oil based finishes).
      A couple of decent options are:
      Sikkens Rubbol Satura Plus and
      Sadolin Superdec Satin Opaque

      In answer to your second point, you could use a water based system over an oil based finish but the level of preparation is much higher. You’ll need to ensure all surfaces are thoroughly washed down and any gloss is abraded so it is totally flat in appearance before overcoating with a water based/acrylic undercoat.

      My general rule though is not to switch from one system to another if you can avoid doing so.

  21. Hi,

    I’ve recently moved into a new build and to add a bit of character i’d like to add mid-height wooden wall panelling to the downstairs toilet (very small – not overly used and adequately ventilated/heated, considering the only moisture would come from splash back from people using the sink).

    Please could you recommend the type of wood i should be using and how to properly prime, paint and finish the panels. I’d ideally like them matt white although the room only has a small window and i’ve seen a previous comments about, and have experienced, yellow tinging on white – can this be avoided?

    Thanks in advance!

    • The choice of wood should be the best you can afford really but since you’re going to paint it anyway I wouldn’t go overboard. Standard pine will do the job just fine – avoid MDF though as it will absorb any moisture in the air like a sponge.

      The yellowing you describe is a characteristic of traditional solvent based paints and is most severe where there is a lack of natural light, hence bathrooms are particularly susceptible. However, since you don’t envisage a problem with excessive moisture you should be OK to use water based paints which do not suffer this problem.

      If a matt white finish is what you are after I’d have a look at opaque wood stains rather than paint. This way you don’t have to worry about primers and undercoats.

      Dulux Weathershield Quick Dry Opaque is an example, there are lots of similar alternatives available.

      It is good practice to give the wall facing side of the wood at least one coat and it’s especially important to ensure the end grains are fully sealed by giving them at least 3 generous coats.

      Give the main, outward facing, sides as many coats as you need to get a good result but 2 or 3 should be fine.

  22. I am using dulux satinwood quick dry paint over primer and undercoat paint which is over gloss paint finish very patchy can you advise how I resolve the doors are grained panelled doors.

    • There are 2 problems here. Firstly, when using quick dry paints over a gloss finish you have to abrade the surface sufficiently to provide a key.

      Also, if you have used an oil based primer and undercoat these need to cure fully before applying a water based finish. Not just dry but fully harden and this can take a few days.

      Leave it a few days, give the surface a quick rub down and try again. A coat of quick dry undercoat will also help, but see how you go.

  23. We have a boxing in unit made of MDF next to what appears to be a leaking shower seal. I’d like to protect the area and wood to prevent future issues (water ended up penetrating the wall). What primer would you recommend for this?

    I also have wooden window frames, that are in contact with water from the shower. I’d like to repaint – again, what would you recommend for this? Thank you.

    • I’d fix the shower first. However, you use a primer to seal the surface in preparation for further coats that provide the actual protection. So, in this regard, use any primer you want (although acrylic is probably the most appropriate for mdf) but ensure you finish with at least 2 coats of oil based gloss to shed any water that’s hitting the surface. The same applies to your window frames.

      If you can remove the boxing-in fairly easily it might also be worth painting the inside surfaces and any exposed edges too.

    • I can remove the top tile and get inside the box unit to paint. The shower has also been fixed by replacing the seal.

      For the primer, would something like Ronseal Super Flexible Wood Primer and Undercoat – White suffice?

      And for the gloss, perhaps Dulux Quick Dry Gloss Pure Brilliant White ?

    • OK but I’d use an oil based gloss myself. If the quick drying stuff is what you already have to hand fine, but give it 2/3 coats minimum – you can’t really overdo it.

      Oh, and give it as long as possible to cure before using the shower again.

  24. We have some beams that are rough and stained black. We want to have them glossed. Tried undercoat and gloss (3 coats of each!) but black still showing through. Have been recommended 2 different things by 2 different people. 1) shellac based primer; 2) aluminium based primer. Which would be best for sealing the black away? Which could go over what we’ve already done?

    • You don’t say but I’m guessing you’re painting them white and you are using a traditional oil based undercoat and gloss?

      What’s happening is the solvents in the paint are dissolving the original stain and allowing it to bleed through.

      A shellac (or spirit based) primer or an aluminium wood primer will work but there is an easier option. Use a water based acrylic undercoat instead (not a primer, because it will be too thin) and then finish with a coat of oil based undercoat and gloss.

      Just ensure the oil based finish has had at least a few days to cure before overpainting with the acrylic.

      If I’m wrong in my assumption and you are using water based finishes just reverse the above and use an oil based alternative.

    • The undercoat and gloss used were dulux waterbased ones. But the gloss was thin retail stuff, not trade.

    • Ok, so you need to use an oil based undercoat and gloss to finish then. But, bear in mind, because of regulations relating to chemicals in paint, nowadays white gloss does go yellow over time when used indoors.

      So what I would recommend is a coat of oil based undercoat to seal the stain problem. Leave it a week to cure and then revert to the water based finishes as before.

  25. I have had new wood panelling installed all around my bathroom. I need to prime and paint it but I am not sure whether I can use acrylic, water based, primer before painting with eggshell paint or do I have to use oil based primer as it is a high humidity and condensation room.

    • The problem with wood paneling is the end grains tend not to be adequately sealed and this is how moisture gets in and causes problems.

      But, to answer your question, you can use an acrylic primer but you’ll get a better finish if you use an oil based primer.

  26. I have pine doors which have been treated with osmo wax oil . I have sanded down, can I now use water based primer/undercoat, or do I need an oil based primer?

    • Provided all traces of the wax oil have been removed, you should be OK.

  27. Having a new veneer external door hung, in small exposed porch. Manufacturer advises no wax, polish or oils. Don’t fancy varnish. I’m worried re: wood expanding and jamming, less concerned about appearance. Can I use an acrylic primer and acrylic top coats safely to protect from expansion?

    • Probably, although you should contact the door manufacturer first because only they know what the door is finished with.

    • Spoke to them – they said actually can use water-based or solvent (oil) based primer (VOC2010 compliant), then ‘stain or paint’. Any specific product recommendation? – online searches give such conflicting advice..

    • Stains tend to be more durable and easier to apply. Sikkens Cetol Filter 7 Plus is one of the better options for a stain.
      For a traditional paint finish Dulux Weathershield is your best bet.

  28. Hi there I ve just painted my front door (teak) with undercoat and there’s like a brown color coming through in patches, I ve sanded it before hand but these brown patches keep coming through even after 4 or 5 coats of undercoat any ideas thanks.

    • Use a water based undercoat or spirit based sealer then undercoat again and it should be OK.

      Zinsser Bin is expensive but quite good. A cheaper option will be to use any brand of water based primer/undercoat.

      Because you’ve already use an oil based undercoat you’ll need to let it cure for a few days before overcoating with a water based product I’m afraid. You’ll have problems getting it to cover if you don’t.

      For resinous hardwoods, such as teak, you should have used an aluminium wood primer but since you’ve already progressed beyond the priming stage the method above will do.

  29. For exterior use, can an oil based primer/undercoat be used with a water based top coat? Lady has requested Farrow and Ball top coat that is being used on soft wood that is being repaired due to rot.

    • It is best practice to use a either all water-based or all oil-based paints, especially outside.

      You might get away with it if the area isn’t too exposed though. You will need the primer/undercoat to cure fully before overcoating it with a water based finish though, so leave it at least a couple of days between coats – longer, if you can?

  30. Hi, I am wanting to paint some pine wood with water based primer and overcoat. However there are quite a few knots in the wood, so I understand I need to use knotting solution. I have two at home (Rusting white Knotting and Jewson knotting solution), the Rusting categorically states not to use under water based paints, the Jewson doesn’t mention anything.

    Please would you advise how to prepare knotted areas where water based paints are to be used?

    • Water based paints can react with traditional shellac knotting. This can result in staining that may be worse than the knotting stain you want to prevent, especially where the finish is a light colour, especially white.

      White knotting contains a bleaching agent so it dries clear and will not discolour light colours of finishing paint. It is safe to use under water based paints although it’s advisable to lightly abrade the surface, when it has dried, to aid adhesion. I haven’t experienced any problems with this approach in the past.

      However, I have been in touch with Rustins and they have found instances where solvent additives commonly found in water based paints have reacted with knotting of all types and their advice is not to use it.

      They say that water based paints do not solubilise the colours from the wood, as oil based paints often do, and, therefore, use of knotting is not necessary.

      In my experience I have found this is true to an extent but not 100% so. I think it’s always worth using knotting in cases like you’ve described.

      I guess the answer is to try a small trial area first, with and without knotting, to see if you do have any problems, although I’d be surprised if you do?

      Sorry I can’t give you a more definitive answer.

  31. Hi I’ve stripped back three layers of paint on the stairs in my 1930s house to the bare pine. About to paint the risers but unsure if I need to apply knotting solution on such old wood. Will they still be resinous? Thanks for your thoughts.

    • There are a couple of situations where you should always consider using knotting. One is on new wood and the other is where the wood is going to be exposed to sunlight.

      Since your staircase doesn’t isn’t affected by either of these issues you are probably safe to carry on without it. There is always a slight chance you’ll get a bit of discolouration over time, particularly with white paint, but it’s unlikely to be severe or particularly noticeable.

  32. I’ve repainted a hardwood front door with Dulux Weathershield water based undercoat and gloss. Am not v.happy with the overall finish and would like to repaint with oil based paint. Will it be sufficient just to sandpaper the water based gloss topcoat and then apply the oil based gloss topcoat

    • Sure, you can do that. To get a better finish you may need to give it a coat of oil based undercoat first though.

  33. In Feb 2014 I painted 7 doors with Dulux Professional Brilliant White gloss. Took the doors all the way back to bar wood. Burn off old paint and sanded down. Used Aluminium primer – 1 coat. 2 coats of Dulux Professional oil base undercoat and 2 coats of Dulux Professional PBW oil base gloss. I now (Oct 2015)find that where the doors (internal cupboard and behinf dressing gown handing on door) do not get very much (or any) sunlight – they have turned a yellowey hue. I read lots about teh issue Dulux (AzkoNobile) had when they initially were forced by EU rules to reformulate their oil base paint VOC mix. I saw before I decided to use the Dulux oil base gloss that the yellowing issue was sorted out. Do you have any views on why the areas getting no sunlight have yellowed / areas getting plenty of sunlight are still Brilliant White and glossy. Should I take this up with Azko-Nobile / Dulux. I feel I should.

    BTW the painting I did back in 1996 using Dulux PBW oil base gloss is still very white and much whiter than the yellowed new paint which is only 18 months old. I would have expected at least 5 to 10 years of PBW “colour”.

    Thanks.

    • Oil based paints will yellow to a certain degree when shaded from sunlight, this has always been an issue.

      The problem you refer to with Dulux was indeed well publicised and they did make changes to their formulation to mitigate this. It’s clear, however, that the changes made still do not result in their gloss performing as well as it used to.

      It is certainly worth taking up with Dulux. I’m guessing they will say your case is an extreme situation and may offer you something as a goodwill gesture. If they do not you are well within your rights to take the matter further via trading standards or directly via the courts.

  34. Our exterior wooden windows and sills need repainting. The condition of the paintwork varies, Some of it is OK, but The south facing sills in particular are very bad, with flaking paint, no paint and open grains/cracks. Can you advise which is the best primer to use. ? Our neighbour thinks Aluminium based primer is the one – but your advice would be welcome.

    • Aluminium wood primer is fine for hardwoods but on soft wood it doesn’t perform very well at all.

      The main causes of paint failure on windows are ultra violet radiation (from direct sunlight) and/or a high moisture content. Direct sunlight is the likely culprit in your case. The open grain you describe also suggests the timber itself has become denatured making any subsequent paint coating much more likely to fail.

      I’d suggest two coats of water based acrylic wood primer. Acrylic primers have a superior adhesion and stay flexible for much longer than their oil based counterparts – and are more pleasant to use. I would go for a pure primer rather than the combined primer/undercoats which are more commonly available. Buying the best quality you can afford is also a good policy.

      After priming you could go for a water based finish or conventional undercoat and gloss (2 coats of gloss would be advisable for durability). It’s a matter of preference – both options have their pros and cons. If you want a glossy finish it will have to be oil based though.

      For areas exposed to sunlight it’s also advisable to avoid dark colours also.

      Hope that helps?

  35. Hi I’m looking to paint some furniture which has a veneer type finish I had some cupboard primer which says is suitable for MDF, melamine etc and was hoping to then use a cupboard paint which is solvent based. With it being a cheaper type of finish on the furniture would the above paints be suitable?
    Thanks

    • You should be ok although you may need to give the cupboards 2 or 3 coats of the finishing paint to get a decent result?

      These primers that are marketed as suitable for melamine and so on are all well and good but you need to do a lot of preparation. This means washing down and rinsing the surface with sugar soap and then rubbing down with abrasive to remove as much of the gloss as possible.

  36. I want to paint a teak sculpture (art project)with white, black and gold. It will be outside for a long time. Can you please tell me what to use ?

    • Aluminium wood primer, oil-based undercoat and oil-based top coats.

  37. My joiner has fitted a new front door and primed it with a water based primer, I didn’t want to paint the inside of it, I want to stain it. How can I remove the primer

    • Since you didn’t ask your joiner to prime the door you could ask him to fit another door and withhold payment until he does.
      Alternatively, you’ll have to give the primer a few days to fully cure and then remove it with fine sandpaper. This isn’t going to be an easy job but it’s the only method that will work.

  38. Hello. Currently painting wardrobe from a light stain finish to a oil based satin. Used a primer and just applied the first undercoat and it has turned the paint really yellow is lots of places all over like its sap or something.

    • You’ll need to use a water based or spirit based primer to stop the stain migrating through. Acrylic wood primer works OK.

    • It look like big yellow streaks almost never seen it before. Someone said it might be wax or sap? Very Scary.

    • Yes, it can look quite ugly.

  39. Hi, i have just put 2 coats of paint on the wall but it has cracked and crazed. Both coats were left to dry properly. Any suggestions on how to cover crazed walls?

    • What was on the wall before? If it was wallpaper did you wash the walls to remove any remaining adhesive?
      If the walls are crazed all over you might be better off covering it with lining paper and starting again.

  40. What undercoat for hardwood ext. window sill please

    • Aluminium wood primer or acrylic primer/undercoat.

  41. I am trying to paint a previous stained stair bannister and spindles white and am wondering which primer/undercoat will be best to use to prevent the stain coming through the white paint?

    • An acrylic primer/undercoat should do the trick. You may find the stain still bleeds through but the acrylic will hold it so it doesn’t work through to subsequent coats.

      Try a test area first with one coat of acrylic and one coat of your intended finish just to be sure. If you still get the stain coming through you’ll have to use a spirit based primer to block it. It’s very unlikely you’ll need to do this though.

  42. I have an unused tin of MDF primer Can I use This on on new pinewood doors before painting with water based gloss?

    • Short answer, yes.

  43. Hi, I’m about to have 2 softwood doors fitted externally to my seperate garage & storeroom. Being softwood there’s a lot of knots in them. I am planning to use aluminium wood primer rather than knotting & traditional primer. However, I have already given these doors 2 coats of clear preservative to add to their protection. Will this affect the performance of the primer in any way? (it soaks in like water). Also, is it really imperative to knot regular softwood doors, especially as these are never in direct sunlight?

    • Using a preservative won’t present any problems provided you allow plenty of time for it to fully dry. A couple of days will be fine.

      If the doors are not exposed to direct sunlight it’s unlikely you’ll have any problems. If you just used a standard primer you might get some discolouration over time. But an aluminium wood primer should stop that happening.

    • Forgot to ask, can I use water based exterior gloss over the aluminium primer or does it need to be oil based gloss?

    • You’ll need to use an oil based undercoat and top coat

  44. I have one tiny shelf in a room that has been made out of MDF – it is only a basement so doesn’t need a ‘top’ finish. I don’t really want to buy an MDF primer just for one tiny job. Can I use a water based metal primer (then undercoat/topcoat)?

    • Yes, of course you can.

  45. If I have prepared a hardwood window with aluminium primer, do I need to put an oil based primer on top before painting the final top coat (with oil eggshell)? I want to ensure that I have the best possible protection to prevent the paint from flaking/blistering and lasts as long as possible before repainting.

    • You’ll need something to block out the colour so something with more pigment will be better. Regular undercoat or an extra coat of eggshell will do the job.

  46. I wanted to paint my exterior wood stained windows however I’ve heard it’s difficult to get a primer to adhere to the existing stain. The wood stain is in good sound condition for the most part so I was considering using International Oil Based 10yr primer/undercoat as I’ve been quite pleased with this product in the past. Any advice?

    • The problem with wood stain is that it can migrate through to the surface of any subsequent coats causing discoloration. You shouldn’t have a problem with adhesion provided the surfaces have been thoroughly cleaned and abraded.

      As a general rule, oil based stains will migrate through an oil based primer and water based stains will migrate through a water based acrylic primer. So to seal the surface you need to use the opposite base primer.

      Some stains can be extremely problematic and you may need to use a blocking primer like aluminium wood primer or a spirit based solution like ‘zinsser b-i-n’.

      Try a test area first and wait for it to dry before committing yourself.

  47. I’m getting some unfinished kitchen cupboards in pine- can you tell me if I use an aluminium primer does it mean that I don’t need to use a knotting solution – I will be using an oil eggshell topcoat?

    • You are correct, aluminium wood primer will do the trick.

      Just to note, aluminium primer does have a high level of volatile organic compounds (VOC’s) – typically 25% – so ensure the room is well ventilated during painting and at least for a few days afterwards.

  48. I’ve painted a new pine cupboard with water based primer and undercoat. Can I use a solvent based top coat as I already have one in a good colour, or would I be better to buy a water based top coat too?

    • A solvent based top coat should be fine. If it’s a gloss finish you may find it dries duller than if you’d used an oil based undercoat though.

  49. It has taken me all weekend to undercoat the doors skirting board and pipes to the bathroom, I used an oil based undercoat, I came to gloss this morning and the paint was splitting, I found out that it is because the undercoat was oil based, you know, oil and water don’t mix. Am I ok to use a water based undercoat on top of the oil based one without too much rubbing down? I do hope so, Thank you

    • Yes you can use a water based paint but the undercoat you’ve just applied will need more time to fully cure, hence the problems you’ve encountered. If you can leave it a few days you should be OK.
      As a rule use a water based undercoat if you are going to be using a water based gloss – but that’s by the by in this instance.

  50. Need. To know if can use water or acrylic based primer on hard wood., as been. Provided. With water based top coats, normally. Would use an oil based primer and leave for a week before next coats but don’t have the time…

    • Yes you can. The only problem with water based paints is they can clog up abrasives when you’re rubbing down so you don’t get as smooth a finish.

    • I used solvent based Leyland Trade Wood Primer on some pine panel doors which had previously been waxed. Prepared the doors with wire wool dipped in white spirit and thought the solvent based primer would cut through any wax residue – which it did – the primer coat is sound. However, I tried to cover the primer with a water based acrylic and it is separating and leaving not only brush marks but actual pools with patches of bare primer between.
      No warning about this on the tin. Leyland technical department said it should be OK to use a solvent based primer with a water based topcoat and advised me to leave the primer to cure over seven days – which I have – but still have the same problem. I will try rubbing down to provide a key but it will be difficult to get into the mouldings of the panels.

      Any ideas please – I know I could use an oil based top coat but I really want to use an eggshell finish which is typically water based.

    • It’s likely that some wax residue has migrated through to the surface of the primer, which is quite common. You could try wiping down the surface again with white spirit and then cleaning with a sugar soap solution to ensure all the residue has been removed?

      You could use a proprietary cleaner/degreaser such as this but the method above will be cheaper and probably just as effective.

      If this doesn’t do the trick then you may just have to use an oil based eggshell or satin finish after all.