Removal of textured wall coating

[pollster]

Hi all,

Please can you help! I've recently moved into a detached Victorian house dating from about 1870 and have some damp problems on the first floor bedrooms
The surveyor informed that the damp problems are due to the exterior walls having been coated in a textured wall paint (a past owner even had it put on the drain pipes etc!).
I need to get this damn stuff off and have any cracks in the render repaired. The surveyor advises that this can only be achieved with a needle gun, however, generally speaking the render on the house is in good condition and I don't want to damage it if I can avoid it.
Surely there must be a way of removing this with a chemical stripper? Has anyone here had experience of removing this stuff?
Many thanks for your help.

Steve

 

[Nemesis]

Give Strippers of Sudbury a ring. It may be possible to remove with a paste stripper - tedious but possibly better for the render.

 

[MdB]

What sort of render is is? I would assume a lime based render from the age and what your surveyor has said but it would be worth checking that it isn't cement. If it is cement you may want to consider removing that as well as there wouln't be any point in just removing the paint.

 

[pollster]

Thanks for the reply folks,

I have thought about having the render removed but I have had difficulty getting hold of a builder who has had experience working with lime. I suspect that it is a cement render underneath the paint as it is in very good condition and therefore been applied in the last 20 years or so (when they didn't know any different!). The problem I have is that here in the Isle of Man, lots of builders have varying opinions. Most recommend cement based render (surprise, surprise) and all advise keeping the render on as it is in good condition and would be very expensive to remove.
I spoke with my Surveyor on this and he recommends removing the paint, leaving the render intact and repairing cracks where required. (surveyors report to the bank).
Ideally I would like to have the whole building re-rendered, but I can't find a builder who's a 100% confident on doing this with lime. I also live in a costal area with driving rain etc and from what I've read hydrate lime render would not be suitable and hydraulic is too similar to cement.

 

[NT]

In most cases upstairs damp is caused by any of:
faulty rainwater goods
faulty roof
penetrating damp
condensation

And textured paint doesnt cause any of those. It can be a problem, but usually isnt. Cracked cement render however more often is.

Hydraulic lime is good for rendering coastal properties, nonhydraulic is too soft. It is chemically a mix of hydraulic and nonhydraulic lime compounds, so is porous and wicks water, more like nonhydraulic lime than cement.


NT

 

[pollster]

My damp problems are only on one wall (facing the sea). On the outside of this wall can be seen large cracks that have had work done to them (albeit badly!). Opposite these cracks on the inside of the house is where the damp is.
I've checked the rainwater goods and there are fine, I do need however an extractor fan for the bathroom.
I have got a loan from the bank to renew the roof (its original) and chimney flashing etc but the bank has stipulated that all the paint, even on the sides of the house not effected by damp, must be removed (the surveyor went on a bit of a rant about the stuff in the bank survey). Nothing however was said about the render in his report. I wish he had, i may have got more money off the purchase price!

 

[Nemesis]

In most cases upstairs damp is caused by any of:

Hydraulic lime is good for rendering coastal properties, nonhydraulic is too soft. It is chemically a mix of hydraulic and nonhydraulic lime compounds, so is porous and wicks water, more like nonhydraulic lime than cement.


NT

Em - that's possibly because non-hydraulic lime is - non-hydraulic. Not at all sure that's what you mean to say? Otr have I missed something?

I think there's a fair amount of twaddle talked about non-hydraulic, too.

It's pretty hard when carbonated.

But - this may be a case of using a very weak hydraulic, if the cement is removed.

But - it may that fixing the cement would help, until it eventually all cracks.

 

[pollster]

Thanks all for your help, much appreciated!

One last question, what type of paint would you recommend I repaint the outside with?

 

[MdB]

One last question, what type of paint would you recommend I repaint the outside with?

I don't think it matters much if your render is cement as you will have lost your breathability anyway.

 

[pollster]

One last question, what type of paint would you recommend I repaint the outside with?

I don't think it matters much if your render is cement as you will have lost your breathability anyway.

True, but if i come to sell it in a few years I don't want another surveyor commenting on "unsuitable paint" again. I'm thinking of going with silicate paint. Hopefully surveyors will like this stuff!

 

[Nemesis]

I think it possibly better than thick plastic stuff!

But - I can't see why, if the render is cement, the surveyor is worried?

 

[MdB]

True, but if i come to sell it in a few years I don't want another surveyor commenting on "unsuitable paint" again. I'm thinking of going with silicate paint. Hopefully surveyors will like this stuff!

The surveyor will probably say "unsuitable render" instead.

If you are looking to cure your damp then I wouldn't worry about changing the paint layer. Sounds like a lot of work for not a lot of point. Try reading the damp FAQ.

 

[pollster]

I think it possibly better than thick plastic stuff!

But - I can't see why, if the render is cement, the surveyor is worried?

My thoughts too, the amount of letters after his name you'd think he'd know cement render when he saw it. Then again I could be lucky and it might be lime rendering, its hard to tell with all the plastic crap over it.
Maybe he should have put "inappropriate render" rather than paint on the banks survey report. I shudder to think the uproar that would cause with builders on the Isle of Man.

 

[pollster]

Below is a snippet from the bank survey, nothing about render? Maybe I should get another survey before proceding?

"However, and of concern is the fact that external walls have been coated . This has resulted in penetrating damp problems internally with damp staining manifesting in the dining room, study and top floor bedrooms with positive pro-tometer readings obtained on these sections and a requirement for immediate action. These applications are often ineffective in a stone/random rubble build of this age and design. The coating application acts as a “trap” forcing moisture to escape internally via the inner leaf, subsequently manifesting as damp patches, with eventual loss of adhesion to the plaster skim and over the long term, worse case scenario is wet/rot dry/rot outbreak affecting timber lintels and joist ends resting in external walls. It will be necessary for vendors to recall contractors responsible for the application under the terms of the Guarantees provided by them. It is essential to be aware that the process required to remove this coating, and it will have to be removed, is labour intensive, hazardous and expensive. This involves a drilling action (it cannot usually be effectively burnt off due to the toxicity of the chemicals at temperature). This often damages the render application with a requirement sometimes for partial reconstruction and re-rendering. With regard to costings we anticipate a minimum of £3,000.00 is likely, excluding scaffolding and re-decoration, and we strongly urge the applicants to discuss this aspect with their Agents/Advocates without delay, and for vendors to be advised accordingly in order to examine the possibility of compensation under the terms of Guarantees provided by contractors responsible for the coating application"

 

[MdB]

My thoughts too, the amount of letters after his name you'd think he'd know cement render when he saw it.

Might be worth getting it tested if you are unsure. (Quick test is to dunk it in vinegar - no fizz means it isn't lime and is probably cement - if it fizzes then it doesn't tell you anything as both cement and lime can fizz). If it is lime render then removing the paint layer would be worthwhile.

edit - having seen that report, it sounds like is more than just a layer of paint. What the surveyor has written makes sense if it is a lime render. If you have a cement render then is sounds like he has missed the fact that this too will trap the moisture.

 

[Penners]

Click here
I've no personal experience of this product, but it looks like what you need.

 

[MDE]

Seems to me that the problem is with the cracked render. The paint exacerbates this by letting the water run off until it enters the cracks after which it is trapped by the render and paint.

 

[pollster]

This does indeed look to be the case. Therefore when i remove the paint i should be able to see where the render is cracked and get it repaired

 

[Matt Green]

That surveyor has drawn a significant amount of conclusions from just protimeter readings.

I wonder if the wall is actually damp or if the internal plaster has damage that the surveyor is attributing to penetrating damp? As Nemesis said: cement holds back water and forces it to evaporate internally, plastic paint or not.

The odds of the embedded timbers being subject to a dry rot outbreak by water coming in solely through cracked render are very slim to none, incidently.

Is the wall(s) in question showing signs of penetrating dampness?



Matt Green

 

[pollster]

One bedroom has lots of what I would call "mini volcano's" circular shapes that crunch when pressed. This wall also has fine salts on the wall.
Another bedroom has a small patch of green/brown mould in the corner under one of the windows. (after reading some of the forum posts, could this be mould be caused by condensation?). I'll try and up load some pics tonight.