Dot and dab on wet blockwork

[GreenGables]

So, builder proposes to add dot and dab plasterboard on blockwork that is clearly damp. The new cavity walls were drenched during construction and the blockwork is dark from moisture internally. If plasterboard is added before the blockwork is allowed to dry out is it likely we will get mould internally? I don’t see why I should agree to this. Surely we should be waiting until the blockwork has dried out. We are currently without windows and doors and the roof has just gone on so hopefully it should start to dry out now. Any advice greatly appreciated. 

[Jilly]

I wouldn't want it, but more because the plasterboard would get damp and go crumbly rather than mould per se. We aren't going to plasterboard until we are weathertight with boards if the windows haven't arrived. See what others think.

[Iceverge]

I'd wait for windows. 

[Radian]

Why would anyone actually want D&D is my question? Just because builders love it due to the speed and low levels of skill required to board out a house, doesn't mean you get a great end result. Inevitably there will be air leaks through the blockwork joints and penetrations and these feed straight into the voids behind the plasterboard. Then there's just 12.5mm of gypsum and paper between you and the outside air washing around the back of the boards. I rue the day my builder talked me into accepting it, threatening lengthy delays to the build if we insisted on sand & cement plastering. Then later on, buggered off for several months leaving us to finish the build.

[Iceverge]

Yup. Sand and cement here and skim. That can be done no problem without the windows in. 

[nod]

9 hours ago, Iceverge said:

Yup. Sand and cement here and skim. That can be done no problem without the windows in. 

Sand an cement need to be dried before skimming Or the skim will burst off months down the line when the heating goes on 

I certainty wouldn’t sand and cement in a building without windows 

 

 

[Iceverge]

@nodOurs was sand and cement and then skim. 

 

Would the sand and cement not be ok on its own?

[dpmiller]

6 hours ago, nod said:

I certainty wouldn’t sand and cement in a building without windows 

what makes that different to rendering on the outside?

[nod]

Believe it or not 

Dot and dab is more forgiving than render 

Whilst the render isn’t effected by damp and wet The finish is Causing it to blow 

This time of year I would normally render two houses out before even thinking about skiming Thats why Dot and dab has become so popular with house builders 

Forty years ago when I started my business We we’re 90% sand and cement Now probably 90-10 for the above reasons 

D&D certainly isn’t cheaper 

 

[GreenGables]

Thanks for all the comments. I think we will allow the walls dry out while we wait for windows and doors.