Wallpaper Questions

You’ll need to wash down the walls to remove any residue of the wallpaper paste that may not be visible and allow to dry out.

Then I would recommend you paint a small area of the wall first just to make sure there are problems such as staining or poor adhesion. You’ll need to thin the first coat with water a little bit in order for it to soak in to the surface.

If there are no adverse reactions then you should be OK to paint the rest of the walls. Any minor stains can be treated with a stain block aerosol.

If you have problems such as extensive staining or poor adhesion then you may need to use a sealing primer such as Zinsser Gardz but, in most situations, you probably won’t need to go this far.

Hi, I am a new decorator, studied in college in 2009 but haven’t been able to do it full time up until a year ago so still lots to learn. I have come across a job with a lot of water damaged areas in the house. The water problem has been solved now. One particular wall is wallpapered and at the top corner maybe 60cm by 40cm the wallpaper has broken away (looks a bit like a baby bird coming out of a shell pattern but on a bigger scale) and there’s a lot of powdery residue that looks kind of what I think is white furry mould growth.

The owner doesn’t want the wallpaper removed for fear of more plaster damage. I’m thinking of 2 things.

One I lightly sand off all the residue that’s there, check if the wallpaper is actually still in ok condition then damp the paper and stick back down with solvite overlap.

Then I’m thinking to apply Zinsser peel stop to put a strong smooth layer over that, then use toupret joint, skim, fill to get a nice smooth area to paint.

Or if the wallpaper is not in good condition to cut certain parts away and then do the same as mentioned above. I have a photo.

Any advice please? I’ve been researching online all day. I like a challenge and want to learn more. Thank you, Amy

The powdery residue is efflorescence which is basically mineral deposits that have been brought to the surface by the damp.

More info here: https://www.designingbuildings.co.uk/wiki/Efflorescence

You will have to remove this before attempting any repair because anything you try and stick to it will come away eventually.

Yes, you could try wetting the paper and then sticking it down but I wouldn’t go any further than this because you don’t know what is going on in other areas that are still covered.

The area could be be sound or you could get paper coming loose for ever and a day.

If they don’t want the job doing properly, that is removing all of the paper, then they have to accept that a patch-up is all they can expect and any risk of it not working is all theirs.

Hi, a couple of years ago we had a whole room re plastered. We then put an emulsion wash over the walls – half water and half emulsion.

A few months later the walls were wallpapered. We are now finding the wallpaper coming off, one strip has fallen completely down. This is a south facing room so quite warm. The decorator supplied his own paste.

We suspect we’ll have to take all the paper off and start again but the decorator says it is all our fault and will not accept responsibility. He says we should’ve asked for the walls to be lined first. We didn’t know this.

Any clues as to why this wallpaper drop might have happened?! It’s a costly experience! Isobel

I would guess that the walls were quite absorbent since you had only applied a wash rather than a regular paint coating. Subsequently this guy has come along and papered the walls and the adhesive has soaked into the wall thereby reducing its effectiveness?

Now, you engaged someone you believed to be a professional to do the wallpapering and he is responsible for the defective workmanship, not you. The first thing he should have done would have been to check how absorbent the surface was and to treat appropriately before going any further. If there was an ‘idiots guide to wallpapering’ this would be on the first page.

In theory, he is responsible for putting the works right at his own cost. You should give him an opportunity to do this, even though you may not want to, simply because it shows you’ve acted in good faith should you need to take legal action against him.

Obviously, if he refuses this offer, or he accepts the opportunity but still makes a mess of it, then you’re entitled to engage someone else to do the work and claim all costs.

It is not advisable since you don’t know how well the paper was stuck down before hand.

You could try brushing a thin coat of paste over the surface, if the paper doesn’t bubble-up and remains firmly stuck then it may be worth the risk, but that’s a judgment only you can make since there is no guarantee you’ll get away with it.

My client has a very sentimental hand painted graffiti design on bedroom wall. He wants to seal/protect it. Then wallpaper over it. But must when needed back , strip the wallpaper and the original graffiti design not affected.

Should I seal with a clear varnish before applying the wallpaper? And what paste is best to use? Simon

There is no guarantee that the graffiti would remain intact but, yes, covering with a varnish should work.

I would use an oil-based varnish to ensure that it isn’t affected by a water-based adhesive although this will result in a slight discoloration of the finish. You can mitigate this by using a polyurethane varnish rather than a traditional yacht varnish though. I would also wait a few weeks for the varnish to fully cure before wallpapering.

Alternatively, there is a product called RockTop that will seal the surface. It is water-based but dries fairly hard and if you leave it long enough to fully cure it may not be affected buy the paste. It’s a risk though.

Ideally, I would cross-line the walls using a ready-mixed heavy-duty adhesive. Then, when dry I would wallpaper using a traditional adhesive such as Solvite or a ready-mixed paste, depending on the type of wallcovering.

If the budget won’t run to lining then just use the ready-mixed adhesive directly. So long as the varnish has fully cured you shouldn’t have any problems with adhesion.

You could use a thinned solution of pva or, alternatively, a thin solution of wallpaper paste. You may have to apply a couple of coats to get the best effect though. It should be virtually as thin as water, in both cases.

Or, you could use Zinnser Gardz penetrating sealer although it’s not something I would use as standard on new plastered walls.

HI, Just decorating a house from the late 70’s early 80’s build and the painted over wallpaper has separated at the joins, it looks like it’s gone back to the plasterboard, can I just seal it with unibond pva clear adhesive and the paint and wall paper or should I get the plasterboard replastered? Thanks, Wendy

If the paper is firmly stuck then you’ll need to fill the joints level with polyfilla and rub down so the joint is not obvious. However, you may find the water content in the filler will cause the joints to swell, thus causing more problems. The same would be true with your PVA suggestion.

The best way to avoid this is to seal the joints with an oil-base paint first. It doesn’t really matter what kind of paint you use, any undercoat or general purpose primer will do so long as it is oil-based. Zinnser Wallpaper Cover-Up is formulated for such situations if you don’t mind paying the extra.

Give it 24 hours to fully cure before applying the filler and that should do the trick. When you have smoothed down the filler you’ll need to seal this in order to get a uniform base on which to redecorate.

You can use a thin coat of water-based paint to achieve this. You should then be able to redecorate without the previous open joints become visible.