Green Building Forum - Cork IWI Over Painted Brick Wall

Cork IWI Over Painted Brick Wall

Tomasz_P — Sat, 27 Mar 2021 21:27:45 +0000

Hi all,
I could have carried on my other IWI thread but I think it is more helpful to start a new one. As a reminder I am renovating a 17/18C red brick coach house.
I think I am going to go with cork for my IWI. Probably 40-80mm. I am getting different recommendations from different suppliers/fitters.
I have one long wall upstairs where the bare masonry is painted. Not too thick but it won't be in a breathable paint. The wall probably makes up about 30pc of the total outside walls for the second floor. The plasterer said it would be best if I removed this before fitting the cork (which has to be fully bonded to the walls). What is everyone's opinion on this? Is emulsion paint really that impervious? I have just had a quote for Â£850 blast a few beams. Don't fancy another 850 or more to do this wall. Downstairs I will be doing it in one painted wall but the walls down there are much more damp.

It actually has me questioning the whole idea of breathable iwi and lime plaster because currently the outside of the house is painted in a modern paint and it is going to be a long while before I embark on the job of stripping and re-finishing that.

Cork IWI Over Painted Brick Wall

Tomasz_P — Sun, 28 Mar 2021 20:58:28 +0100

Wall in question...

Cork IWI Over Painted Brick Wall

kristeva — Sun, 28 Mar 2021 21:36:05 +0100

Posted By: Tomasz_PHi all,
I could have carried on my other IWI thread but I think it is more helpful to start a new one. As a reminder I am renovating a 17/18C red brick coach house.
I think I am going to go with cork for my IWI. Probably 40-80mm. I am getting different recommendations from different suppliers/fitters.
I have one long wall upstairs where the bare masonry is painted. Not too thick but it won't be in a breathable paint. The wall probably makes up about 30pc of the total outside walls for the second floor. The plasterer said it would be best if I removed this before fitting the cork (which has to be fully bonded to the walls). What is everyone's opinion on this? Is emulsion paint really that impervious? I have just had a quote for Â£850 blast a few beams. Don't fancy another 850 or more to do this wall. Downstairs I will be doing it in one painted wall but the walls down there are much more damp.

It actually has me questioning the whole idea of breathable iwi and lime plaster because currently the outside of the house is painted in a modern paint and it is going to be a long while before I embark on the job of stripping and re-finishing that.

I think your instincts to abandon a breathable system in this part of the house are probably correct. If the paint isn't breathable and you don't want the expense or hassle to remove it then there doesn't seem to be any point. At least this won't be as critical for the house if it concerns the upper floors. Sometimes you have to compromise, as someone on here wisely told me when I first joined, you can't keep everything breathable or original.

How do you plan to strip the paint from the external brick? I too have to strip the back of my house (lead paint), but I'm worried about taking off the protective face of the brick with the paint. If this were the case I'd probably apply render, or even EWI.

Edit: btw, what was the cause of your damp on the ground floor?

Cork IWI Over Painted Brick Wall

Artiglio — Mon, 29 Mar 2021 08:13:29 +0100

I removed various layers of differing masonry paints from the brick facade of an 1870â€™s building , had a trial of the DoF system that really was not particularly effective and would have taken months if the trial was indicative of its performance.
Finally went with chemical strippers, PeelWay7 worked but was considered incompatible with the mineral paints that were to be used on the stucco , so used Keim STS7 which was very effective if expensive and time consuming / messy. I cleaned it of with a cold water pressure washer , apparently a hot water washer would have been better. But you need a fully sheeted scaffold and cleaning up at the end of each day is tedious. ( my building was in a terrace so containment and cleaning were very important , not such an issue if detached).
I hate to think what it would have cost if it had been done by a contractor. I got through nearly 2k worth of stripper alone.

Cork IWI Over Painted Brick Wall

Tomasz_P — Tue, 30 Mar 2021 22:32:41 +0100

Thanks for all of your info on the products. We are detached and have a bit of land so at least clean up would be easier. The brick isn't in great condition.

@Kristeva you are right. I have to make compromises somewhere. My wife would certainly agree with that. I think it is less important on this second floor.

There is a combination of things causing the damp I believe.
1. Higher ground level outside
2. Poorly maintained French drain - soon to be rectified
3. Cement based floor covering - being rectified as I type
4. Internal cement render and gypsum plaster on ground floor - now mostly removed

Cork IWI Over Painted Brick Wall

kristeva — Wed, 31 Mar 2021 18:38:08 +0100

Posted By: Tomasz_PThanks for all of your info on the products. We are detached and have a bit of land so at least clean up would be easier. The brick isn't in great condition.

@Kristeva you are right. I have to make compromises somewhere. My wife would certainly agree with that. I think it is less important on this second floor.

There is a combination of things causing the damp I believe.
1. Higher ground level outside
2. Poorly maintained French drain - soon to be rectified
3. Cement based floor covering - being rectified as I type
4. Internal cement render and gypsum plaster on ground floor - now mostly removed

How are you rectifying the cement base floor Tomasz? I have a screed floor in my kitchen I'd like to get rid of.

Cork IWI Over Painted Brick Wall

Tomasz_P — Thu, 01 Apr 2021 07:50:14 +0100

Hi Kristeva,

I have taken it all up. It is being replaced with a limecrete slab over Glapor. It has been a massive job!

Cork IWI Over Painted Brick Wall

kristeva — Thu, 01 Apr 2021 09:35:12 +0100

Posted By: Tomasz_PHi Kristeva,

I have taken it all up. It is being replaced with a limecrete slab over Glapor. It has been a massive job!

Nice! There's surprisingly a lot of work in involved in replacing a floor. How much is this setting you back? I Considered digging mine up and reinstating a timber floor.

Cork IWI Over Painted Brick Wall

Tomasz_P — Mon, 05 Apr 2021 20:46:49 +0100

I don't like to say it out loud! The insulation and slab including installation was in the region of 18k but that is before I have added all the labour costs of getting it ready + replacing tiles. Obviously if I had gone down the self install route it would have been a lot less but I didn't have the time for it. The Norfolk based company I used have been excellent.

Cork IWI Over Painted Brick Wall

Tomasz_P — Thu, 09 Sep 2021 20:56:40 +0100

Posted By: ArtiglioThanks for putting a real life cost up, is that for the full 140m2 you mentioned in another post?

Yes that is for the full 140m2

Just getting to the point of deciding which flirting to use. Another big cost!