Plaster boarding 200 year old solid external wall

[wotsisname]

I'm using plaster board with PB adhesive to replace sections of the old crumbling plaster in my kitchen.
But just a bit worried about a section on the external wall. It doesn't have a cavity, so was wondering if i should be taking any precautions against damp penetrating from the outside over time and damaging the adhesive and PB. I don't have a damp problem so am i fretting over nothing
Advice appreciated.
Thanks

 

[Richard C]

Difficult to say, although the wall may feel dry to the touch it may well have a higher moisture content; I would (& have) use Duplex Board (foil backed) or similar on battens to minimise the risk of permeating damp on single skin walls which is always a possibility. As your already aware, plasterboard will disintegrate fairly quickly in a damp environment. Solid walls are usually also "cold to the touch"; battening gives you the opportunity to line it with a layer of high efficiency bubble/foil insulation.

 

[roy c]

The answer to this is to buy Polystyrene backed plaster board, and dot and dab it on the suspect wall.if you are doing two walls abutting then put some dry wall adhesive down each corner of the wall( about 4" either side of the corner,) then put some 9" dpc over the top of it. Then dot and dab your boards as normal and this will stop any damp tracking on to the edges of the board.You can also do the same with the dpc along the bottom edge of the wall which will also stop damp touching the board. You can get poly backed boards of all sizes, but I would use the ones that finish at about 22mm, they are not cheap but very effective, I have a house over 100 years old and the walls are between 16" and 20" thick stone and no dpc, I have done all my walls like I said above and have had no problem with damp. And that was over 10 years ago when I did them

 

[wotsisname]

Ah! I didn't expect such good advice so quick.
But of course it raises more questions - so much to learn here.
One point i didn't say is that the wall are far from flat. That's why i like to dob and dab to even it off, rather than battens. A quick search on google for plasterboard types comes up with the thermal type (presumably the poly backed?), and the damp proof/foil backed (the duplex?). Both sound perfect except, do you know if i can use PB adhesive with the foil-backed? I'm a tight fisted g?t and will choose the cheaper option.
I can see the benefit in that both have a water-resistent membrane. There was also a moisture-resistant board where the actual plaster is resistant to moisture ingress. Wondered if anyone has experience with that in this situation.

 

[Richard C]

It’s not recommended to D&D foil backed board as the adhesive bond will only be as strong as the adhesion of the foil to the board (not very); although I’ve never experimented with it! Not sure if moisture resistant PB would be suitable; it’s resistant to moisture, meaning it shouldn’t turn to mush, but that doesn’t prevent moisture permeation & I’m not sure how well the board or adhesive you stuck it on with would stand up in the long term. I would use something with a membrane; foil or polly back as Roy suggests. In fact the method Roy describes sounds a good one; I’ve not had the need to try anything like that before.

 

[jbonding]

you cant dab foilbacks i would also steer clear of dabbing it because the dabs will keep showing through when its cold outside, have a look at pages 17 to 20 on here this system is really easy. http://www.lafargeplasterboard.co.uk/Installation/IG_Handbook_lo_res.pdf

 

[wotsisname]

Thanks everyone.
I've been chewing this over and getting some prices. Likely to go for the poly-backed board to get the insulation properties as well as damp blocking plus i've found dot and dab fairly easy. But the Lafarge adjustable battens with foil backed board suggested by jbonding are attractive because they get around another problem. A previous owner has cemented and replastered little sections, and I can't shift them, so with with the battens i can go over.
Anyway, decided to take the plaster off the rest of the kitchen first before start boarding - get the horrible dusty work out the way. So there's a couple of weeks before have to make up my mind.
I'll post up how i get on.
Cheers.

 

[wotsisname]

It's taken me a long time to get this done; needed to sort out some wiring, plumbing and clear plaster off rest of wall. And inclined to put things off. Used foam-backed plasterboard with D&D adhesive. Looks great. All it needs is a coat of paint. Thanks for the advice.