Help needed...

[pmr1]

Hello All,

I posted this on another forum a few days ago but didnt get any responses, so hopefully someone here can help?

Ive just had a wall knocked out in the kitchen and have boarded and plastered half the room. While in the process of doing so I moved the fridge, under sink base unit etc. Both are on an external wall beneath a work surface and window above. On moving them I noticed white powdery staining on the plaster. It was obviously damp and the plaster crumbled when touched. Im pretty sure the cause is a poor seal around the back door, which will be sorted with mastic. The badly affected area is directly next to that door. I need to know how best to fix. Ive taken off the damp plaster to a point where it no longer crumbles or shows signs of damp.

How far up do I need to go with the plaster removal? I read somewhere that you should go 1m higher than the highest damp spot? That would take it into a tiled area above the work top.

The depth of the plaster is over an inch thick, how do i best build up the thickness on the area thats now back to brick? Im thinking either double boarding and skim or bond the wall? should i be adding anything to avert any more damp problems? Im ok when plastering a standard wall but havent ever patched plaster in like this.

Photo attached.

Thankyou for any help.

 

[Danny]

@flynnyman @irish_spread @D4mp they should help

 

[Jurek]

Don't dab it dude. Or bond it. If it's penetrating damp brush fix the seal or whatever, brush all the crap off it with a stiff brush and use a renovating plaster like kingfisher or wykamol then skim on top but not to a polish. The wall will be able to breathe and dry out in its own time. If you can't be arsed doing that and want to dab it use dri fix foam then you won't get the bridging and the big damp spots where you've dabbed it showing through. Or do a destructive test on it the whole house might need doing

 

[raytheplasterer]

if you had damp your blockwork /bricks would have some kind of mould. you wasted your time.

 

[pmr1]

If it wasnt damp, what was it? the plaster was sodden. There are also black stains on the brick rising up from the floor.

Ive just looked up the kingfisher stuff, it looks ideal. I had never heard of it before. Would it be right to pva the wall, a thick coat of kingfisher then a layer of multifinish (which isnt polished). Am i on the right track?

thanks for your help jurek

 

[stuart23]

Could be condensation, did you have a tuble dryer in kitchen?

 

[Silky]

white and dusty residue sounds like efflorescence. Might need some salt inhibitor? slurry mix painted on the brickwork once you have removed the mould from the bricks, wire Brush/sugar soap will do it. salt inhibitor and/SBR 25:1 for mixing water mixing the render to 2:1 for first coat then same again but 3:1 for float coat then key and skim. If it's thick just dub out render first. You can get a limelite system from tarmac that does a good job too. slurry, backing and skim. When using the limelite finish be sure to read the instructions because I'm sure you have to mix then leave a few minutes then mix again before application. Search for rendering and plastering after damp course completed for some guides and ideas.

 

[Silky]

2.5l rest water in a builders bucket for mixing water for mix. sorry had a beer.

 

[jansen]

I always take plaster off back to brick 1m high, drill holes along bottom corse of affected area and inject with a sealer, leave to dry for a few days if possible then Sand and cement it back up