Dot and Dab concerns

[chameleon001]

Hi,

Just looking for some advice on whether I’ve done the right thing. Our house (1950s build) had blown plaster which you could peel away with your hands. I knocked all this off and had the walls dot and dab boarded and skimmed. The ground floor is suspended wood floor with crawl space below. I have only done 3 rooms so far.

I am coming to realise that this may have not been the best approach and that I should have got the rooms wet plastered instead. I don’t any issues yet but I am concerned that the gap between the plasterboard and walls will act as a channel for cold air from mortar gaps and the crawl space below to surround the rooms and reduce the efficiency/ warmth of the house. Also concerned regarding mice etc finding their way into this space.

Our plasterer didn’t recommend wet plaster due to more issues with cracking. Likely it would have just taken him longer to do and higher cost?

So really the question is, am I thinking too much into this and this is now standard practice or am I likely to find issues. If so are there ways I can mediate things? I could get into the crawl space and inject expanding foam around the room perimeter to seal the base of the plasterboard?

Thanks,

Dan

 

[Mr Chibs]

Do the plasterboards sit on the floorboards? or is there a gap?

If there is a gap, fill with expanding foam, before you put the skirting boards on.

I wedge a piece of plasterboard packing under the bottom edge of the plasterboard when dot n dabbing, (remove next day) that way if there is any bounce in a wooden floor, this is not transmitted onto the boards which leads can lead to cracking.

I wouldn't beat yourself up over what you have already.

 

[chameleon001]

Hi,

Cheers, there is a gap between PB and floor. Rooms are completely finished but if needed I can get under house and seal from below. Likely I’m overthinking this then, that’s reassuring.

Thanks again,

Dan

 

[endecotp]

I'd worry that squirting in expanding foam from below could expand and push the PB off the wall!

 

[noseall]

I'd worry that squirting in expanding foam from below could expand and push the PB off the wall!

Not once the dab has set, no. Just try pulling a board off the wall and you will quickly understand.

 

[John D v2.0]

Yes it's a valid concern and best practice is to parg cost the wall before the plasterboard, and to use a continuous dab around the edges of the wall.
Expanding foam would be worth it though, you don't want air blowing behind your plasterboard!

 

[noseall]

use a continuous dab around the edges of the wall.

This how we do it.....

Untitled

• noseall
• 15 Aug 2014
• 3

 

[John D v2.0]

This how we do it.....

Excellent, and that's not even an external wall! Doubt it's useful on an internal wall unless you already have issues with suspended timber floor.

 

[chameleon001]

Hi all,

Thanks for your help, kind of annoyed I had the walls dry lined, should have gone for traditional plaster but just didn’t think.

Suppose the best I can do is try and block up as much as I can. Going to seal the lounge from underground, then have similar issue in loft with 2 rooms being dry lined too. Luckily I am re insulating the loft so I can get expanding foam down the gap from the loft.

Lesson learnt

Cheers,

Dan

 

[chameleon001]

Quick check with regards to the best foam to use. I don't want to pop the plasterboards (although if I did I could have an excuse to rip them off . I have found this stuff - Soudal Low Expansion expanding foam. Low expansion so hoping less risk of popping the boards?

Any tips welcome!

Thanks,

Dan

 

[Mr Chibs]

Just use regular foam, but don't fill the gap, all in one go.

 

[noseall]

You won't pop the boards.