remove damp plaster, then replaster

[jphenning]

Hi

I am after some advice regarding a issue I have in one of my bedrooms.

over the winter and the storms, I have had some issues with the flashing at the back of my house above the conservatory. we are getting a friend to sort out the flashing for us.

The problem I have is that the wall under the window in my spare bedroom has now got a damp problem where some plaster fungi is growing. I have removed the wallpaper to get to the fungi to remove it and the plaster has just crumbled. it is so wet that after a few scrapes with a wall paper scraper I have manged to expose the brickwork in a couple of places.

I now believe that I need to remove all the damp plaster to brick treat the wall with a PVA solution to prevent the damp and fungi and re-plaster.

is this correct?

and how do I:-
1) go back to brick
2) how many coats of plaster do I need to put on?

Thanks

JP

 

[ree]

There have recently been endless posts on this very subject, perhaps if you read some back numbers it would help you?

The damp is probably condensation dripping down from the window(s).
Do not use PVA or browning on a damp wall.
You could spray or paint the brickwork with a fungicide.
Fungi as in black spots or fungi as in growths on the wall?

The guide to plastering referred to above is almost useless for your purpose.

 

[Micilin]

You can approach in a few ways. Having stopped source of water.

One, get it back to brick and clean off the wall properly.

Brush on a SBR:Cement:Fine Sharp Sand mix 1:1:1 , covering completely but leaving a keyed surface.

Apply scratch coat of 3:1 sand: cement with propriety waterproofer (with fungicide) to spec.

Float coat of 4:1 as above.

Skim

Leave a day between operations.

Usually just the float coat and skim onto a clean wall will suffice, but the above is belt, braces ,support truss and suspenders.

 

[jphenning]

You can approach in a few ways. Having stopped source of water.

One, get it back to brick and clean off the wall properly.

Brush on a SBR:Cement:Fine Sharp Sand mix 1:1:1 , covering completely but leaving a keyed surface.

Apply scratch coat of 3:1 sand: cement with propriety waterproofer (with fungicide) to spec.

Float coat of 4:1 as above.

Skim

Leave a day between operations.

Usually just the float coat and skim onto a clean wall will suffice, but the above is belt, braces ,support truss and suspenders.

Hi Micilin

A couple of questions if I may.

1. when you say clean off the wall once it is back to brick is this any excess dust, debris etc..

2. Brush on a SBR:Cement:Fine Sharp Sand mix 1:1:1 , covering completely but leaving a keyed surface. what is a SBR and the 1:1:1 mixture I take it is as 1 part Cement, 1 part sand what is the 3rd part?

and the float coat is that 4:1 cement and 1 part sand? mixed with water?

I am not really up with mixture ratios.

 

[Micilin]

1. Yes wall back to bricks and all dust etc off with damp brush
2. Google SBR
3 yes with water and waterproofer as per scratch coat