Plasterboard expand?

[stephenward]

i've put up my plaster board, plasterer coming tonight, then i hear i should have left a 25mm gap where plasterboard meets floor/ behind skirting to allow for expansion, is this correct?

My plasterboard is pretty snug to the floor in some places, should i try taking an inch or so off the bottom?

 

[Richard C]

Don’t worry if you haven’t left a gap, it won’t matter.

It’s normal to leave a gap at the bottom but around 8-10mm is more than enough. Don’t know where you got the 25mm gap for expansion from but it’s brolacks; plaster, plasterboard & even timber studwork will never expand or contract that much. The gap is primarily to allow space so you can get a lifter under the board to allow easy adjustment when fitting to ensure the boards fit snugly against the ceiling & against each other. A gap may be advisable on concrete ground floors or where the floor could be subject to wetting; ordinary plasterboard disintegrates if it gets wet to any degree!

 

[NickB_99]

A gap may be advisable on concrete ground floors or where the floor could be subject to wetting; ordinary plasterboard disintegrates if it gets wet to any degree!

Does leaving a gap apply upstairs as well as down?
I had heard about leaving a gap downstairs. Useful if you get a leak downstairs. I had heard it was building regs, so not really optional.

I also find a gap useful as it stops me picking up bits off the floor when skimming.

Stephen - was it upstairs or down?

 

[Alastairreid]

I had heard it was building regs, so not really optional.

a bit of common sense maybe, never seen it stated in any regs or drawing specs though.
but as you say diynewbee it helps prevent picking up dirt from the floor when applying the skim coat.

 

[Richard C]

I had heard it was building regs, so not really optional.

Not as far as I'm aware

 

[NickB_99]

I had heard it was building regs, so not really optional.

Was told it on my plastering course - but I know they are not always held in high regard!
I've had a quick search on everyone's-favourite-search-engine, and can't see any ref to building regs. Some that say it avoids damp rising, but nothing specific for regs.
So chances are it may not be fact.

 

[Richard C]

Was told it on my plastering course - but I know they are not always held in high regard!

Nothing at all wrong with plastering courses as far as I can see; never been on one but they should provide a good basic training, knowledge & understanding of the materials used. What really matters is how a person takes advantage of & extends that knowledge & understanding into a true skill; it takes years & you never stop learning.

I've had a quick search on everyone's-favourite-search-engine, and can't see any ref to building regs. Some that say it avoids damp rising, but nothing specific for regs.
So chances are it may not be fact.

There are many Building Regulation myths around, particularly in the world of conservatories & double glazing . You could try looking in ------------ the building Regs. & I would be really interested to hear if you do find anything. There are one or two regulations that can catch you out on refurbishment work but I don’t believe leaving a gap between the bottom of the plaster & the floor is one of them; it is, however, a point of good practice in circumstances previously quoted.