Mouldy walls after new plastering

[Scott10]

Hi,

After some help please!

Around 3 months ago I had a damp course fitted. I also had the suspect walls fully replastered. The new plaster was quite thick in some areas ~50mm. I waited 6-8 weeks for the plaster to dry. I then painted it with a 'sealer' paint. Not sure the exact title of the sealer but it was very watered down in consistency and sticky to touch as it was drying. I then coated it with a matt paint, fitted new skirting boards, painted them and then chaulked the gaps.

All was well, but a few weeks afterwards I noticed severe mould growing. It is green and black in colour and in some areas white and fluffy and is generally getting worse! It is coming directly through a. the new paint (no higher than half a meter from the floor), b. through the caulking and c. even now directly through the wooden skirting board!

I am pulling my hair out with frustration. Could you please advise me of your reccomendations for how best to cure it?

Many Thanks,

Scott

 

[Richard C]

50mm of plaster is pretty thick by any standards, was it a render base with skim over or all plaster? If you’ve had a new damp course fitted, presumably the walls were damp & it could take up to 6 months for it all to dry out properly, particularly with a moisture laden 50mm slapped over the top. I think you may also have made things worse by sealing the walls, what exactly did you use; was it PVA, paint or some form of waterproof sealer?

I think, perhaps, you didn’t leave things long enough for the moisture to escape & the walls to dry out thoroughly. The damp already in the bricks has to go somewhere & if you block its escape route, you’ll get problems. Give it a chance to all dry out (in this weather!) & see what happens; unfortunately you may have to redecorate.

 

[Nige F]

50mm slapped over the top. I think you may also have made things worse by sealing the walls,. The damp already in the bricks has to go somewhere & if you block its escape route, you’ll get problems. Give it a chance to all dry out (in this weather!) & see what happens; unfortunately you may have to redecorate.

Agree entirely a breathable paint would`ve been right.......personaly I would try power sanding the paint to maybe break the seal and go over with a trade..non-vinyl emulsion........Ask on the decorating forum

 

[Cummins]

Sounds to me as tho you have dry rot growing thro the wall. Dry rot will grow thro the cement in the bricks looking for food eg Wood. It exists when damp levels reach abt 23% wet. It also needs other conditions to survive. Look at the other side of the wall ur under your floorboards and you will be surprised at what you will see. you need to reduce the moisture level of that area to well below 23% to kill the dry rot. you may also have to inject the wall with dry rot treatment to kill the growth.

Sounds serious and if not treated correctly and quickly will be serious!!!!!

 

[Richard C]

50mm slapped over the top. I think you may also have made things worse by sealing the walls,. The damp already in the bricks has to go somewhere & if you block its escape route, you’ll get problems. Give it a chance to all dry out (in this weather!) & see what happens; unfortunately you may have to redecorate.

Agree entirely a breathable paint would`ve been right.......personaly I would try power sanding the paint to maybe break the seal and go over with a trade..non-vinyl emulsion........Ask on the decorating forum

Blimey Nige, you seen the date on that one!