Dot and dab - door linings

[Jever]

Hi all,

I'm refitting a bungalow and have rebuilt the partitions using 100mm breeze blocks.

I wanted to have the whole lot plastered using bonding followed by a setting coat but I can't find a plasterer capable of/willing to do this. Every time I speak to a plasterer they tell me they only do dot and dab and then skim over the plasterboards, so I am now preparing the walls/partitions for dot and dab dry lining.

I've watched a few videos on this and it appears that the electrical knock-out boxes (25mm deep) are screwed directly to the face of the blocks, so that if the plasterboard finishes flush with the electrical boxes, there'a a 12 or 13mm void between the back of the plasterboard and the face of the blockwork. Is this correct?

Assuming I've got this right, I now need to fit the door linings to finish flush with the face of the plaster skim coat.

So, if I have 100mm blockwork and 25mm of plasterboard plus void on each side of the blockwork and allow 3mm for the skim coat, I reckon the door linings need to be 156mm (100mm for blocks, 2 x 25mm for dot and dab on each face then 2 x 3mm of plaster on each face) thick. Have I got this right?

Would love to hear from any dot and dab gurus out there.

Regards

Jever

 

[23vc]

Yeah all of that is pretty much entirely correct. You’ve got a bit of flex with the thickness of the skim around the lining so it doesn’t have to be millimetre accurate.
Wouldn’t stud walls have been easier tho?

 

[Jever]

Thanks, that's helpful.

Yes, you're right, stud walls would have been easier/cheaper but we originally wanted bonding and finish on the blockwork, it's just that we can't fins a plasterer that can (or is willing to) do it, so we're stuck with dot and dab on the blockwork.

By the way, if I'm putting dot and dab onto dry blockwork, is it wise to coat the blocks up with PVA to reduce the draw on the water? What would the professionals do in this instance?

 

[23vc]

No need for PVA, Dab adhesive will go straight onto dry block work.