External wall sealing

[Paul]

(With apologies to anyone who had already seen this on free.uk.diy.home)

My parents are convinced that they need to sign away several thousands of pounds on a treatment known as Protectacoat for a house which has solid brick walls with pebbledashed render - this is at least 50-60 years old and now there is some penetrating damp.

Protectacoat apparently seals the existing render with some sort of rubberised layer and claims to provide a waterproof barrier against further ingress of rain. This sounds highly suspect to me.

I'm wondering whether it would be better (and possibly cheaper) simply to have the existing pebbledash render removed and a new one re-applied?

I'd appreciate any thoughts on this.

Thanks

Paul

[Stuart Noble]

It is highly suspect. The last lot I ripped off was not only harbouring damp, but various colonies of insects. Worse than useless because water gets behind it and can't get out. Would probably work if the render was sound but, if that were the case, you wouldn't need the treatment.

[Owain]

Why is the damp penetrating now and not during the last 60 years?

Do you have a blocked gutter?

Owain

[Mike]

Search for comments on this sort of product in

There have been numerous comments, all negative.

[Andrew Gabriel]

By what means has this been shown to be penetrating damp? If the investigation involved the company intending to do the work, you're almost certainly being ripped off. They probably wouldn't diagnose condensation for example, as they don't know how to fix that (although it is the cause of most damp problems).

You need to find the cause of the damp. Pebbledash is remarkably waterproof (much more so than plain render as the pepples tend to deflect much of the water off the wall in the first place, and are not absorbant anyway). If pebbledash fails, it usually falls off the wall completely.

[Cicero]

================= IF........ if the walls are allowing damp penetration then it's quite probable that some of the render has 'blown'. If this is the case then it might be worth having the house re-rendered since patching can be an expensive and possibly unsightly business.

Several thousand £££s for a glorified coat of paint / water-proofing solution seems very much like a rip-off.

Last year I had my 'semi' re-rendered (plain - not pebbledash) for just under £1900-00 so this is some kind of guide price if you're in the West Midlands.

Cic.

[andrewd909]

thousands

a reputable painter and decorator?,one should be able to give you the correct advice after seeing the walls.

[Chris Bacon]

Look at the cause of the damp, guttering, cracks, build-up above damp, etc. If the dash is sound but gets excessively wet for periods due to such problems, then the remedy is generally simple - cure the cause. If the render is knackered, it needs removing and scraping back up (not hard cement mortar, use 1:1:6, refuse any offers of render with "plasticiser" in it which is not what you might think!).

I had a "protectacote" (SP?) salesman around, who seemed to be in a bit of a hurry, but promised that their contractors would make good damaged render, and apply this miracle coating. A demo. involved a clear tube with a disc in the middle painted with the "stuff". One half of the tube contained wated, which when inverted did not penetrate the paint. The other half was connected to a rubber bulb/tube, which could be squeezed to push air in, which bubbled through the paint. At first sight this was impressive. I don't know how long it would be efficaceous for in a "real" environment, though, with dust and what-have-you; the decorative effect won't last 30 years IMO, and what do you apply then?

[The Natural Philosopher]

Actually that is not true.

Ive go a couple of areas of (new) render where drving rain soaks the render and if it then freezes, its started pushing the paint off and rubbishing the render.

Someone whos opinion I trust reckons that a coat of muckite over the paint will stop it.

I agree its not a cure all for everything, but it has its place.

Obviuously if damp gets in behind it, its worse than useless.

[AlexW]

I was told by a "reputable" damp company that my soft sandstone wall should be sealed with a moisture impermeable coating.

I didn't do it after looking at info from the above site and getting some technical info from the Society for the Protection of Ancient Buildings

were clearly either cowboys or just incompetent as there would be no way for trapped moisture to escape thus accelerating the decay ... I would imagine that pebbledash would be effected in a similar way.

If you can find the source of the penetrating damp (gutters, down pipes, gullies, roof tiles etc etc) it might be simple to eliminate it rather than the symptom.

Have you compared the cost of re-rendering to this proposed treatment?

Alex

[Stuart Noble]

"> They were clearly either cowboys or just incompetent as there would be

Providing a coating adheres to the surface, and is in itself waterproof, no moisture should get in in the first place. This is near impossible to achieve with render because invariably there is a gap between it and the wall

Penetrating damp is usually just rain hitting a porous wall. You're lucky if there's an obvious source. If the wall is already painted, or you can bear to make it so, solvent based masonry paints are very effective IME

[AlexW]

I am not an expert but I would imagine your comments are assuming you have:

a) a physical DPC to stop moisture rising behind the render b) no chance of moisture condensing or getting in to say a cavity and c) no water contained within the wall already before treatment.

In my case a) & c) were certainly not true as the solid 2 foot random stone wall had been damp for over a hundred years (and still is on the outside ;)).

The coating suggested was not a render but a clear proofing agent which would totally seal the wall thus frost etc would just blow the surface right off (which had already happened in some areas without any "help").

Or pouring down a wall keeping it permanently wet maybe which was the root of my comments?

Alex

[AlexW]

Looking at

this looks like a render system in any case which means they may actually remove render rather than just covering it.

[Chris Bacon]

Why do you say that? I have looked, and can't find any info. on what their product is. I remember the salesman demonstrating his model, and saying that any defective would be replaced before the "Protectacoat" was applied, but not that it was a render in itself.

[AlexW]

Some of their before and after pictures show a terrace with (perfectly nice!) brick work which *appears* to be have been rendered in the after picture ... of course they could have rendered and then applied it on top as you suggest ... so a better approach might be to phone them and ask what its all about!

The web side is a bit vague though! Plenty of testimonies ... I wonder how many are 10 years down the line?

[AlexW]

Or get a demo ... which you did ;) as I see from your earlier post!

[Tony Bryer]

Moisture will get in to the wall because it is being generated within the building and the internal surfaces are far from being a perfect water barrier. IMO it is much better to have a wall that can breathe.

The website talks about their holding company Turner Enterprises Ltd 01660216 which Companies House confirms has been trading since

1982. But it doesn't say who your contract is with: Protectacoat Limited 02330326 was dissolved in April 2004, last accounts made up to 2000. If there is any connection between this and the current business I'd be on my guard.

[The Natural Philosopher]

That is why you have impermeable membranes and controlled ventilation in (some) cavity walls.

As usual th short answer is it depend on what is happening, why the wall is damp, and what harm its doing.

[Paul]

Just to expand on a couple of points

1 - I'm told that Protectacoat will remove 'loose / blown' render and pebbledash and dub it out to the same thickness; then they apply a base coat of fibreglass resin based render; on top of this goes a trowel applied layer which is then rollered to give a 'decorative' effect. There is no indication of the thickness of this coat.

2 - The inside of the wall is definitely damp but whether this is condensation or saturated masonry I can't really tell.

Thanks everyone for your comments; you've crystallised my reservations about the wisdom of using this process.

Paul