Quick way of covering damp/salty brick walls

[markwm]

Currently redoing one of our rented houses. There's a pantry area that's just had all the plaster hacked off because it had blown in places due to salts. The said plaster had been on decades mind.

I'll be treating the walls with salt neutralizer and then regarding re finishing the wall there's a number of options:

1. Dot and Dab - not really suitable given damp/salty nature
2. Rough in with drycoat or limelite
3. Use lime plaster - Something our plaster has no experience of
4. Dry line the wall with batterns then board - Only problem with this solution is the time it will take ME to battern it and pack out where it's uneven etc etc.

Now I've just had an idea of using duplex(foiled backed) boards and simply screwing them straight to the wall with masonry screws/tapcons. What do you think of this idea? I could also sandwich a membrane between the boards and the wall too.

 

[jbonding]

why is salt (eflorescence) forming?

 

[markwm]

200 year old bricks, most of the salt is located behind chimney stacks so I assume it's from the days when they had real fires.

 

[jbonding]

"200 year old bricks, most of the salt is located behind chimney stacks so I assume it's from the days when they had real fires."

I can't see how this will cause eflorescence.

 

[markwm]

see chimney salts http://www.diydoctor.org.uk/projects/chimneydamp.htm

 

[jbonding]

any chance of a picture?

 

[markwm]

Imagine an old lime mortar brick wall with some pure white table salt thrown on in certain places. Just looks like that really.

 

[jbonding]

how quickly does the salt appear after you have wiped it off?

 

[roy c]

dot and dab on 1" polystyrene then dot and dab half inch plaster-board on top. You could use polystyrene backed plaster-board, but the other way you can make sure that the poly touches each other in the corners.

 

[markwm]

Can you dot and dab with poly backed boards?

Once had a plaster who insisted you could dot and dab with foil backed boards and they all came off.

 

[roy c]

Yes there's no problem dot and dabbing with poly back boards, but you can't do it with foil-back. I first did dot and dabbing 20 years ago for an architect and what we did was use foil-back boards, and unibonded them and stuck 1" polystyrene on them, and left them for a week and then dot and dabbed them on the wall. Now you can get all different size's of poly back.We tend to use 22mm poly back boards (thats the overall size) but you can get them as big as 50mm. Make sure you put plenty of dabs on the board, we put them on every 6". Check the wall for level first and size your dots accordingly when you put your board to the wall get a long straight edge and tap it gently horizontly and vertical and check your level. We always cut all the boards to size first and put pencil marks on the wall where the boards join, that way when you dot you know where the edges of the boards meet. Always put dots all around socket holes and make sure you keep the dots close together on the bottom of the board (where skirting is going) because you dont want the boards "buckling " when the carpet fitters stretch the carpet...If you are dot and dabbing a damp wall with poly back boards it is a good idea to stick some 6 or 8 inch DPC up the corners, this will ensure that the corners of the boards don't come in contact with the damp walls....