How important is butting up the joints?

[baker332]

Hi,

I'm in the process of adding plasterboard to a ceiling before a skim coat.

How important is it to get these flush? there is a small gap of maybe 3mm between a couple of these?

Also when jointing two plasterboards some of the boards cannot be fixed with screws along the joint line due to lack of available joists - how much does this matter? Would tape and skim do the trick or just crack over time? Is it better to get these fixed somehow? Is it possible to use a glue behind to stick to the celotex insulation instead?

Many thanks

 

[baker332]

Any advice here guys?

 

[Dereekoo]

Close butting no issue as plaster will squeeze through scrim and fill gap. All free edges of plasterboard should be fixed

 

[bsr]

If the joints don't line up with joists then you need to either attach noggins behind or remove the boards and trim. They must have wood behind or they'll crack.

 

[baker332]

If the joints don't line up with joists then you need to either attach noggins behind or remove the boards and trim. They must have wood behind or they'll crack.

Thanks for the response.

Slightly annoying then as I can't view the joists as they're under 40mm of celotex - would need to remove this to add the noggin.

 

[baker332]

You think I could use some thin wood under the joists or does it need to be firm? Assume the latter?

 

[Dereekoo]

You think I could use some thin wood under the joists or does it need to be firm? Assume the latter?

Are you talking about joints along the line of the joists or perpendicular to the joists

 

[baker332]

Are you talking about joints along the line of the joists or perpendicular to the joists

Perpendicular - thinking I could stick it underneath to the celotex, would it work?

 

[Dereekoo]

Perpendicular - thinking I could stick it underneath to the celotex, would it work?

In that case OK to join with scrim and skim. My kitchen ceiling was done like that 8 years ago and still no cracks, joists about 500mm centres, don't forget to stagger the boards joints

 

[baker332]

In that case OK to join with scrim and skim. My kitchen ceiling was done like that 8 years ago and still no cracks, joists about 500mm centres, don't forget to stagger the boards joints

Thanks Dereekoo.

I have a couple of boards however like this:

Where the board on the left is essentially hanging 30cm or so - would it hold up with scrim tape?

 

[baker332]

Also here:

 

[Dereekoo]

Thanks Dereekoo.

I have a couple of boards however like this:


View attachment 322221

Where the board on the left is essentially hanging 30cm or so - would it hold up with scrim tape?

Not advisable but other than taking boards down and nogging/sistering alongside joists you are where you are

 

[baker332]

Not advisable but other than taking boards down and nogging/sistering alongside joists you are where you are

Is it advisable do you think? I mean I could do it this weekend - what are the chances of cracking if I were to say inject silicone underneath to stick to the celotex to help or would the scrim tape do most of the work?

 

[Dereekoo]

Is it advisable do you think? I mean I could do it this weekend - what are the chances of cracking if I were to say inject silicone underneath to stick to the celotex to help or would the scrim tape do most of the work?

Impossible to say, yer pays yer money and yer takes yer chance

 

[baker332]

true - I'll try for some longer screws angled !