painting plastered wall

[scorpio stu]

Hi I am painting a stud wall that was recently built seperating a lounge and dining room. There is a fine crack between the plaster board and the original brick part of the wall. I have filled it several times but the fine crack keeps coming back,any ideas.

Thanks in advance
Stu

 

[joe-90]

Have you tried a flexible decorators caulk?

 

[Richard C]

Is it a corner joint? Was it taped before plastering?

 

[scorpio stu]

Hi,it is not a corner joint it is (if you can imagine) a room that was knocked through (many years ago)and had about 2ft of wall left either side.We decided to seperate the two rooms again and have had a stud wall built across it to seperate the rooms again so the stud and plasterboard now join onto the brick part of the wall.Thats what keeps cracking,yes it was taped properly as well.
Fofgive me for sounding ignorant,can decorators caulk be painted over with a roller ?

Thanks for the replies

 

[roughcaster]

Why not tape over the cracks again?

 

[scorpio stu]

Tape over with I think it's called scrim tape and then fill and sand again ?

 

[Richard C]

You could try caulk but it doesn’t sand particularly well & you will probably see it. When extending a wall in-line with studwork & plaster board, just butting the plasterboard up to the wall will inevitably lead to cracking where the two meet. It’s caused by different rates of expansion between the original wall & the timber studwork supporting the plasterboard. Re-taping is unlikely to work either & you’re probably stuck with it unless you fancy more radical remedial work.

To avoid cracks, it’s best to use blocks/bricks similar to the original when extending a wall or blocking up an opening. If studding must be used, the best way to marry stud to brick is to hack the base plaster off the wall to expose the blocks/bricks by at least 300mm & overlap the wall with the plasterboard using drywall adhesive to bond the plasterboard to the wall. Fill & skim out level with the adjacent wall with Bonding plaster, tape the join well & then skim the entire wall.