‘Miracle’ Exterior Wall Paint Systems

Painting the exterior walls of your home is expensive and, to be fair, a bit of a pain. It wouldn’t be so bad if you could just do it once and forget it but, with most conventional paint systems, it’s a job you have to keep doing every 3-5 years.

So a solution that claims to last a lifetime has to be tempting right, even if it does seem a bit expensive? Or, perhaps, it’s all a con – how can you know for sure?

Why do you need to paint the outside walls of your house?

The exterior walls of your home are under constant attack from wind and rain and, to a great extent, they do a pretty good of defending against this. Both traditional single thickness walls and modern cavity walls will keep the weather out, although neither system is perfect.

Traditional, single-thickness, masonry and brick walls absorb moisture and allow its release by natural evaporation. Over time though this damp can build up and lead to internal damp and mould, especially where walls don’t get a lot of sunlight. In severe cases, excessive moisture can also cause timbers to rot.

Modern cavity walls have two skins with an air-gap in between which prevents moisture from passing from one side to the other. But a combination of poor design and workmanship sometimes means this gap isn’t maintained and this can lead to damp problems. Some cavity-wall insulation materials have also been incorrectly used and can act like a sponge and allow water to penetrate internally.

Also, with either system, there are weaknesses, especially where there are openings for windows and doors. It’s very difficult to allow for the differential movement of timber or uPVC and masonry – moisture will get in eventually.

Masonry walls are also subject to movement and this will, inevitably, lead to hairline cracks in the mortar and cement render. Water can get in via these cracks and become trapped, leading to all manner of problems.

It makes sense then, if you can, to paint the exterior walls with masonry paint to shed water and to avoid a lot of the associated problems.

However, it’s only paint and won’t last forever. Dirt in the atmosphere will discolour the surface over time. Hairline cracks will develop, where there is movement, and allow water to get in. Mould growth can also be a problem, especially with North facing walls, and this will need treating from time to time.

So are Miracle Coatings the Answer?

Businesses offering exterior painting solutions can make some rather extraordinary claims about the effectiveness of their systems.

  • Typically they’ll say their paint system will last for 10 – 20 years, or sometimes a lifetime.
  • They’ll claim they can cure damp.
  • They’ll say their paint is revolutionary and is some kind of technological development.
  • Their system will applied by spray and will be ‘many times’ thicker than normal masonry paint.
  • They’ll sometimes offer some kind of insurance backed guarantee or warranty.

Sounds wonderful, doesn’t it? But if their paint is so good why don’t the likes of Crown and Dulux offer something similar?

Maybe it’s a conspiracy to get you to keep buying their products? After all, selling an exterior paint that lasts forever will just put them out of business?

Or, maybe, they already formulate their paint to be as good as is possible – and anyone saying otherwise is talking nonsense?

Decide for yourself.

What these businesses don’t tell you…

They’ll be very cagey about the products they use. Not because they have secret ingredients but so you can’t do any of your own research.

The cost will be much higher than if you had the work done by a regular painter and decorator.

The work may be done by a different company to the one you’ve paid your money to.

The guarantees they offer will have a lot of small print and exclusions. You may also have to pay extra for ‘this guarantee’ and it’s unlikely to cover you for normal defects like hairline cracks in the walls or around openings.

It’s likely also the business that did the work will have to be given the opportunity to come and rectify any problems before you can claim your money back.

Questions you need to ask anybody painting the exterior of your home

Regardless of which company you want to paint your home, be it a conventional painter & decorator or one of these ‘miracle coating’ companies, there are a few basic questions you need to ask.

  • What products do you use and where can I find data sheets for these?
  • Can I contact some of your previous customers?
  • Do you have public liability insurance and, if you have people working with you, employer’s liability insurance?
  • What qualifications do you have?
  • Who will actually be doing the work?
  • How much will the work cost, exactly?
  • If I have to pay money up front, what is this for?
  • What happens if the work is not satisfactory or there are defects?
  • What guarantees or warranties do you offer and which company is underwriting these?


I had my house coated five years ago with a white textured ‘breathable’ wallcoating which was sprayed on and supposed to last for 15 years. I live by the side of the road in a coastal location and the white paint very quickly became discoloured…. READ MORE…

I had my house coated five years ago with a white textured ‘breathable’ wallcoating which was sprayed on and supposed to last for 15 years. I live by the side of the road in a coastal location and the white paint very quickly became discoloured especially the roadside walls. It desperately needs repainting and I wonder what is the best paint to use.

I have been very disappointed in the original coating and unsuccessful in getting help in remedying the situation from either the paint producers or the contractors who did the work, both blaming each other for the problems. The 15 year guarantee was no use.

My local painter and decorator is willing to repaint by hand, but we need to know what paint to use. I would really appreciate your advice as I am worried that if we use the wrong paint it will exacerbate the problems.

I have not given the name of the contractors or paint providers but can provide these details in confidence if necessary. The contractors have gone out of business! Jennifer

Hi Jennifer, an all too common problem unfortunately. These companies often use industrial paints bought in large quantities in order to maximise the profit with no regard for actual performance. It is, therefore, impossible to say with any certainty what your walls have actually been painted with?

However, you are where you are and, assuming the actual coating is still firmly attached to the walls with no sign of bubbling or flaking you may be OK. The discolouration could be down to surface contamination that has simply been painted over – or any number of reasons really?

Generally speaking, you should be OK to proceed with painting over the existing coating using a standard water-based masonry paint. For coastal areas there are high-performance options available such as Dulux Trade Weathershield Maximum Exposure Smooth Masonry Paint which are more expensive but specially formulated to be longer lasting.

I don’t recommend such products normally since the small added benefit is often not worth the extra expense but if you don’t want to commit to regular re-painting it may be an option worth considering?

You also suggest your property is next to a busy road and, unfortunately, this is going to result in paint discolouration no matter what. There are treatments you can apply that act as a dirt repellent but given you already have a suspect paint coating I would be wary of adding any further complications at this time.

I would also suggest that if you go ahead and use either a standard masonry paint, or the maximum exposure alternative, that you try a trial area first just to ensure the discolouration doesn’t persist by bleeding through to the surface. This is unlikely but is definitely a precaution worth taking.

My 1930`s semi was last painted in 2001 with Sandex exterior masonry paint. I am looking to redecorate now. There are a few movement cracks in the walls and was recommended Bedec extra flex coating… READ MORE…

My 1930`s semi was last painted in 2001 with Sandex exterior masonry paint. I am looking to redecorate now. There are a few movement cracks in the walls and was recommended Bedec extra flex coating. I am just a bit concerned about moisture getting trapped underneath. Should I be and can I put it on top of the existing coating please? Cis

According to Bedec their masonry paint is microporous and flexible so, on the face of it, you shouldn’t be concerned.

However, they don’t back up these claims with any further information and appear to have no official certification by any recognized body.

Their own product data sheets are not easy to find and, also, don’t give much away. It is a product that is widely stocked in trade merchants although this isn’t necessarily an assurance of quality.

There are several similar products which offer superior flexibility over conventional masonry paints but I would be weary of recommending any since they are only intended for use where the cracks are superficial. They are not a solution natural structural movement in the walls. This is usually minor but still strong enough to crack masonry, so a film of paint is hardly going to make much difference?

It’s likely, if you do opt for this solution, that the effects are only temporary and, within a few months, the cracks will have reappeared. The best remedy is to rake out the existing cracks and repair with cement or a resin-based filler, then re-decorate as normal with ordinary masonry paint.

If you wish to proceed with the Bedec solution then ensure your contractor provides some form of written guarantee and is contactable (in other words, he actually lives in the same area) and is solvent (is going to be still in business a year later).

See Also
A terrace of houses all painted a different colour
Exterior Masonry Paints
Painting a wall with a roller
Painting Cement Rendered Walls