Is this common

[akist]

Quite some time ago I hired a carpenter to build a flat roof over a couple of rooms. I am now looking at it and realise that i would have preferred the joists and noggins be flush against the walls so as to give me something to fix the edges of ceiling boards on. Now there is a gap all around which might need a lot extra work to fix something to pick up the ends of the plasterboards.

Am I right?

 

[oldbutnotdead]

Not really. What's the gap- 50mm or so? That'll be fine. The wall boards will support the edges. Up to you how you set the ceiling boards so the bare end joints are supported.

 

[akist]

There will be no wall boards I am using hardwall. The gap is like 95-100mm.

 

[freddiemercurystwin]

It's not normal, or were the walls built after the floor? In any case you are where you are and you'll have to fit some battens off the joists or whatever, awkward but it is what it is.

 

[conny]

There will be no wall boards I am using hardwall. The gap is like 95-100mm.

By hardwall, do you mean it is going to be backing plaster finished with a top coat? (Just so I have it clear in my head).

When taking ceilings down, (and I've done a few of them!), or lifting floorboards, I have never come across joists tight up against the walls. There has always been a couple of inches gap. The ceiling boards will be well supported by the last joist and, if you do the ceiling first, the wall coating will cover the ends of the ceiling boards, thereby giving it support.

 

[Wayners]

Consider dot and dab on those thermalite blocks or the plaster may crack up.
I'd scratch a 5mm grove along the wall top and seat plasterboard in with polymer grab or drywall adhesive. That will secure edge

 

[akist]

It's not normal, or were the walls built after the floor? In any case you are where you are and you'll have to fit some battens off the joists or whatever, awkward but it is what it is.

The walls were in place before the ceiling joists and noggins were installed.

I am fitting 12mm ply up on the ceilings and the plasterboards over, may be the ply will steady the plasterboards at their edges.

Else, yes it would be a hassle...

By hardwall, do you mean it is going to be backing plaster finished with a top coat?

Yes it is called "hardwall" as per photo, snd then multi-finish

, if you do the ceiling first,

Yes ceilings are done first then the walls.

Consider dot and dab on those thermalite blocks or the plaster may crack up

Ahhh, those blocks gave the plasterer nightmares. He ended up bringing the garden hose in and drenched literally the blocks and even then the plaster cracked.

But he also laid it too thick in one coat. Which is very wrong. The instructions and other plasterers say you need a couple of coats to achieve 11-15mm thickness, not all in one go...

Anyway the multifinish appears to be without cracks, how long before cracks might appear? Weeks? Months?

 

[foxhole]

Is it an external wall ? With no insulation?

 

[Deleted member 174758]

If you board the ceiling then board the walls (dot and dab, etc) the wall boards will generally support the edges of the ceiling boards. Boards can carry 50 to 100mm beyond the joist without any problems. This is pretty much standard practice, and has been all my life (but hey, I'm only a chippy). Unless specified the joiner/carpenter would not normally fix extra support noggins at the wall edges or put a joist hard against a wall, where it would be liable to transmit sound into the wall (because joists move, whereas masonry doesn't) or (in the case of an external wall) potentially wick moisture from the masonry and go rotten over time. Additionally plumbers and sparks often need that gap on multi storey buildings (saves 'em drilling through joists)...

 

[akist]

Boards can carry 50 to 100mm beyond the joist without any problems.

I have been adding noggins and supports, every foot or so, to pick up the edges of the ceiling boards. They are 37.5mm insulated boards, softer at the back, so we need good support for them.

The whole process is a pain, especially on the side of the room over the cavity wall because I cannot access the other side to secure the pickups, so on that side I will just use timberlocks.

Here are the "easy" noggins I have added, this is a partition wall and I have access on both sides so I can nail those noggins in from both sides. Still I have to cut them at an angle since I cannot "drop" them in from above, and have to twist them in place in between two joists. Not optimal.

 

[^woody^]

A ceiling board can overhang 100mm or so no problem