Mould Problems - Only One Bedroom

jpaul said:
(maybe others will comment) I would be carfeul with a jet wash, I played one on a previous rendered property I had N/side with algae, and can damage/erode render surface.
that's why I thought Pocca was suggesting mechnaical removal for paint.
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I also see warnings against wire brushes due rust stains, so I can't win really
 
Pocah said:
You need to strip all the decorations, clean and then apply a coat of Thompsons One Coat Damp Seal or Zinsser BIN ( Shellac based paints ) to all surfaces in the room. Walls and ceilings, so that you go at least 18" past any signs of damp. Then you can decorate. The Thompsons is easy to use and you can happily roller it and get perfect results.

Since you haven't been able to find any reasons then guess here is that your external wall paint has become porous and thanks to the terrible amount of rain we had in the winter the wall is now saturated. Vapour can cross a cavity even if it is insulated. There have been a lot of problems with people reporting old damp areas causing problems again. My answer to this is always to paint the exterior with a Pliolite based masonry paint such as Johntone's Trade Stormshield Pliolite. Should last you at least 15 years.
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I've just had someone out who advised everything exactly as you have in this thread. So much so I wonder if you are him.

Part of me wonders if the house needs to expel water through the outer skin? If this doesn't happen then fine, obviously pliolite is the best way forward. But pliolite I've heard isn't "breathable". Could it be possible that the wall is damp and has "thrown off" the paint coating on there at present, resulting in the situation I'm in?

That's my only worry and just wanted to bounce this idea off you as you seem like you know your stuff
 
Solus said:
I've just had someone out who advised everything exactly as you have in this thread. So much so I wonder if you are him.

Part of me wonders if the house needs to expel water through the outer skin? If this doesn't happen then fine, obviously pliolite is the best way forward. But pliolite I've heard isn't "breathable". Could it be possible that the wall is damp and has "thrown off" the paint coating on there at present, resulting in the situation I'm in?

That's my only worry and just wanted to bounce this idea off you as you seem like you know your stuff
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LOL! No it wasn't me.
It could well be that it was painted when it was wet with the wrong paint and as you say it has thrown the paint off or the paint has been compromised in the past and water has got behind it. I mean yes it is important that the outer coating is solid hence the suggestion to use Pliolite. Shellac based interior paints like Thompson's One Coat are breathable so they will let the moisture slowly evaporate in to the house. But you are right that no masonry paints are breathable. I have never found this to be an issue, and I have treated some very damp walls. Your problem is a bit unusual though because you have injected foam insulation which slows down the drying out process. Normally I would suggest a few small vents in the outer wall but that's pointless with foam. I think the main thing here is we aren't entirely sure where the damp is coming from and to treat all the potential sources as fast as possible to stop more water getting in and the then the walls should dry out very slowly by themselves.
Tanking Slurry is a cement based paint you mix in a bucket, lol. It dries light grey. It has the advantage that it sticks to wet walls, is waterproof, repairs cracks, and is breathable, and is also cheap! But it's god awful hard work to apply and the walls must be free of paint. Your house ends up looking like a Nazi gun emplacement but hey, look at all the advantages! Eventually of course you would paint it with any masonry paint. It's a cheap solution.
Another answer for the outside would be to have the rendering chopped off and replaced but that's expensive. A final option would be to have the front of the house partially or full clad with upvc. That makes it waterproof but allows it to dry out because there would be a gap between the cladding and the front of the house. You could DIY that though, really easy. You just need to research it. White cladding is cheap.
I think what I would do is paint the interior and exterior and wait and see. If you still get signs of camp then consider something more drastic like exterior cladding. I think it will be fine though.
 
I've had someone out who advised using a needle gun. Is this correct as I thought this was mainly for metal?
 
Pocah said:
Good idea. I have never used one personally but I believe they are very good for what you intend. Hard work mind.
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Thanks mate, the guy impressed me. Just awaiting his quote which I should receive this evening.

So far i've had:

Plasterer:
Mesh and K-Rend: £4800
Hack it all off and new cement render (paint not included): £3500

Handyman:
Scaffolding, Hire of High Powered Jet Wash, Fill Cracks with Mastic, Stabilise, 2 Coats Pliolite: £1650

Painter & Decorator:
Sand blast including scaffolding with sheets to contain mess. Removal of all sand and waste. Chase out cracks and tyrolean render to blend in. Stabilise, 2 coats pliolite including materials: £3600.

General Builder:
Scaffolding, Needle Gun, Chase out Cracks and Hollows, tyrolean render to blend in, stabilise, 2 coats sandtex (I may ask for pliolite), additional wall vent added: TBC
 
The quote never came. I guess it's either spend out money on someone decent to do it all to renovate the current render for around 3500 or replace it with parex for the same money.

Only other option I have is obviously get all the paint off and use tanking slurry, which I can't see me doing at the height I would need to go to. That's £3500 I'll never see again. Houses aye?
 
Ciga have agreed to remove all of the insulation, any debris and insulate the front elevation again.

Should I take them up on their offer or just get it removed?
 
yes then strip and redo .. 5k is a lot .. but you will have peace of mind ..
once the water gets in it's hard to get out ..
 
remove the insulation .. have the outside wall stripped and redone ..
everything in that cavity will be wet from the outside to the inside ..
it will take a while to dry out .. you may want to go as far as stripping the plaster ..
the thing I don't understand is why it's not in the room under that one on the same wall ..
then again it might be but it's not showing because it's a warmer room .. in use more .. fire place ? more radiators
I'd have the room down stairs checked a damp meter on the walls would give an indication ..
 
The cause of the mould was found to be condensation on to walls with voids. So imagine you have a fridge next to an oven, it's condensation central.

The internal cavity was found to be dry including the insulation, they have offered to replace it to ensure it's installed properly.

So the whole issue with the render was irrelevant, though obviously still needs to be done.

Ventilation is obviously a must for me to add.
 
if that were true then would it not be in all walls ? mostly the bathroom ?
if it was me .. id be taking a brick out to check ..
have the other rooms got ventilation thru the walls ?
they may be telling porkys because they would be libel .. it could be they used the wrong insulation and this time round there going to use the right stuff

hey it's your house
 
so faulty installation is a known problem, especially in Wales
https://www.bbc.co.uk/news/uk-wales-42165358

In 2016, CIGA agreed the CWI was to blame - and said they would cover the cost of removal - but would not pay for repairs to the house.
...
But Mr Gray took his case to the Centre for Effective Dispute Resolution and won.
...
He added: "We are aware of a small number of complaints relating to Welsh Government-funded schemes, however the majority of complaints in Wales relate to energy supplier schemes.
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... sounds as though they were held liable for consequent damage in that case
 
flea.rider said:
if that were true then would it not be in all walls ? mostly the bathroom ?
if it was me .. id be taking a brick out to check ..
have the other rooms got ventilation thru the walls ?
they may be telling porkys because they would be libel .. it could be they used the wrong insulation and this time round there going to use the right stuff

hey it's your house
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After reading the news article about South Wales, I'm definitely going to get it removed.

All other rooms do have vents upstairs. I have photos of the insulation from bore holes that were drilled by Knauf insulation to check. They did indeed comment on the voids, but said the insulation and cavity was dry.

Could the insulation be dry by now (as we've had a hot summer) and only become a problem with continuous rain?

The bathroom is on the rear of the property also, which we've never had a problem with.
 
I think maybe its nothing to do with rain.
Foam insulation can cause damp because it doesn't let moisture escape from a house. As you already found out, voids can make the matter worse because they form cold-spots that moisture condenses on. Bedrooms tend to be particularly affected by damp because they are often poorly ventilated and believe it or not every person in the room gives off about a pint a night in moisture! That's a lot of condensation. In a normal house the walls absorb that condensation, and eventually vent it to the outside world, but the moisture can't get through foam insulation. Whether you have the insulation removed or not you still need to tackle the ventilation in the bedroom to dry it out and keep it dry. I would say keep a window slightly ajar for at least a year, maybe permanently.
 
Do you think there's a chance I could get them to sort the front render out, or is it unlikely the insulation has caused the cracks? Windows left on night stay when we are in bed, and to prevent the Mrs from closing them completely as she tends to do, I'll be installing a permanent vent.
 
I don't know if these no win no fee claims work when the original installer has gone in to liquidation, I've also read somewhere that if over 8 years since install date you can't claim. It's been 11 years according to Ciga.
 
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not sure if you said when the insulation and rendering/painting were (relatively) done, but from the articles people have successfully claimed remndering/painting.

Speak more to neighbours to see if anyone else has issue ? and contact support group ?

EDIT: ok 11 years for cwi
 
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