Dab and Dob, thickness of the adesive

[john59]

I am planning to plaster boared over a fire place using the dab and dob method and was wondering how thick would the adesive have to be to make a good contact to the brickwork and is it worth pva ing the bricks before hand to stop suction.
Many thanks in advance.
John

 

[HandyJon]

As thick as you want/need want it to be.

If it needs to be very thick use dots, which are plasterboard pieces embedded in the dabs which is the adhesive.

 

[jbonding]

do a search on dot and dab

 

[john59]

Cheers chaps, will do a search

 

[Nige F]

Flob a Lob..Bill and Ben the Builders..Taught Bob all they know and he still knows nothing

 

[mrscalex]

I've been taught to end up with a 1 cm air gap if all things are equal. But they rarely are. The height of the dab when it goes on the wall is a slightly different matter as you may be trying to take up uneven brickwork. It also depends how wide the dab is as it's the overall mass you're trying to get consistent.

The Lafarge guide suggests 10 in long dabs, 2-3 in wide and 1 in high. But I put it on more like 2-3 in high.

It looks like it ought to be the easiest job in the world but it's a bugger to get right at first and I'm still getting used to it. It's well worth practicing and then pulling the board off the wall to see how successful your dabs have been at spreading/taking. Expect the board to break as it comes off after the practive but board is cheap and the finish is permanent unless you are having it skimmed.

If you don't get enough dab on, the board will flap. Too much and you'll never press it home evenly.