SBR slurry prior to dot and dab

[tireetim]

I'm going to dot and dab my living room (1920's semi with cavity walls) which were lime rendered and are now back to brick. Although I don't think there are any damp problems, a builder has advised as a precaution to paint a slurry coat of SBR / Cement on, then paint on a tanking, then render over it (to take away the shiny surface and stop condensation) before dot and dabbing. This seems like an overkill to me and lots of work. Also, I thought that the SBR slurry can be used as tanking on it's own?
Please can anybody advise on this. I was thinking to just paint on SBR / Cement then dot and dab straight onto that.
Thanks.

 

[TheVictorian]

The builder does not know what he is talking about.

 

[tireetim]

Thanks, I thought that sounded a lot or unnecessary work.
Does the SBR slurry then dot and dab onto it sound ok?

 

[roy c]

If there is definitely no damp coming thru or on the wall then I would get a grinder and criss cross the wall with it to give the dry wall adhesive a key. And if you have got the room I would dot and dab polystyrene backed plaster board on the wall. It will give you a good warm wall. A lot of the lads on here don't like dot and dab but I have done it for years and most of my old Victorian house is dot and dabbed . But I knocked all the inside plaster off and scratch coated all my walls and dot and dabbed on the scratch coat. Have a look thru some of my albums and it will give you an idea of how it works and also put plenty of dots of adhesive on your boards..If you have enough room then I would use metal framing its great stuff and easy to put up and you can put insulation in to give you a warm wall

 

[tireetim]

Thanks Roy C ! I've already taken it back to brick and put on the SBR Slurry so I could either dot and dab straight on to that or put a scratch coat on. It would be much easier for me if I can get away without putting the scratch coat on but if you think it's necessary then that's what I'll do. I hadn't thought about using insulated plasterboard but that sounds a good idea.

 

[roy c]

The reason I had to put a scratch coat on was because my walls are about 18" to 20" thick and it is all stone rubble and anything else that went into the mix. But you might get away with it on your slurry. Make sure you put loads of dots on the boards and make some wedges to put under the board so it gets them up tight to the ceiling. Is there any work to do on the ceiling? As to make a good job you will have to put some scrim tape on top of your board and fold it on to the ceiling. Get yourself a nice piece of 4"x2" timber about 5 or 6 foot long and you use it to tap on your boards to get them flat. Put a level on the wall to see how Plumb it is and you can thicken or thin your dots out to get a true wall tap with 4x2 and check with a large spirit level as you go..

 

[tireetim]

Thanks Roy. It's getting a new ceiling - I pulled the old lath and plaster one down as it was not in good condition. I did the same in another room and dot & dabbed but taped all the joints (TE boards mostly). Have done quite a bit of taping but my skimming needs practice so I will probably tape again as I know it will look ok. I didn't do any prep on the brickwork of the other room but there is one small patch of penetrating damp from a crack in the external render. Just trying to learn and avoid similar in the living room by tanking it first.