Studding internal corner edges for plasterboarding?

[jamie765]

Almost ready to start plasterboarding my DIY Loft conversion (had a builder do the shell/structure only) but realised the internal corners have no studs for the plasterboard to screw to.

Is this standard or has the builder messed up? I would have thought a stud is needed on every corner? Do I now need to cut into my insulation boards and fit studs along every edge?

Even wall to pitched roof edge is missing a stud as you can see below:

 

[oldbutnotdead]

Oops.
How much air gap is there behind the insulation boards? If there's plenty you could push the boards back and fix slating battens or similar to the hidden studs.
Or (messy & don't know how well it would work) get some longer board screws & skew screw them into the hidden studs
Or (if the insulation is firm) Gripfill non-solvent down those edges
Easy mistake to make when setting out, give builder a ring and rip the ****. Unless he was building from detailed drawings done by someone else....
Nice neat cuts on the insulation, vile job innit

 

[^woody^]

Is he off school? It's a schoolboy error.

The worst crime there and which would be more concerning, is by whoever specified that construction without a layer of insulation across the timbers. Thats pre-school.

I would not be too concerned about the noggins, not ideal but not a major problem, but rather than rip the lot out, use some panel adhesive along the edges to secure the board to the insulation.

 

[dontbelieveawordofit]

if it was smaller areas i’d say butt the board edges up and run gripfill up the corners . when it’s scrimmed and skimmed it shouldn’t budge. however that’s really not acceptable. and given the extremes of moisture and heat and cold are greater in the loft it’ll expand and contract and look like a car crash in 12 months.

 

[jamie765]

After seeing these replies agree with my initial thoughts, I decided to redo those corners - removed and recut insulation, and fitted new timber to support the plasterboard

 

[jamie765]

Is he off school? It's a schoolboy error.

The worst crime there and which would be more concerning, is by whoever specified that construction without a layer of insulation across the timbers. Thats pre-school.

I am planning to put 15mm over the gable wall, which I is rendered (and not tiled) on exterior. Currently 90mm between all studs, with OSB on outside and tiled box dormer.

The bathroom plumbing is already in place so can't add extra 15mm layer to the walls. However it will be fully tiled, so hoping that should be OK without insulation over the studs?

On a side note, would a vapour barrier be needed on the stud walls? (both bathroom and bedroom exterior walls). Am planning to put one on the flat roof but wasn't sure about walls

 

[oldbutnotdead]

If you tape the insulation boards to the timbers and each other (foil tape) that'll give you your vcl.
R value for tiles is about the same as plasterboard ie f***-all. Depending on what plumbing has been done, you could get extra on the bathroom walls...specially if its plastic.

 

[jamie765]

If you tape the insulation boards to the timbers and each other (foil tape) that'll give you your vcl.
R value for tiles is about the same as plasterboard ie f***-all. Depending on what plumbing has been done, you could get extra on the bathroom walls...specially if its plastic.

I reeeally don't want to mess about with the plumbing as the waste pipes took me a long time to get perfect so I could fit a slim profile shower tray without much trouble and without raising it with an easy plumb kit...plus it would involve ripping off my glued down flooring to do so as you can imagine, I'd rather not go down that route!

When you say - 'Depending on what plumbing has been done, you could get extra on the bathroom walls...specially if its plastic' - do you mean if I left it as just 90mm Celotex between studs, but put a seperate plastic vapour barrier over the walls? I was looking at the Visqueen vapour barrier here but they only sell 100sqm, which would pretty much cover all my loft walls and ceilings...

https://www.insulationshop.co/visqueen_vapour_barrier.html

 

[oldbutnotdead]

Nah, was talking about getting an extra 15mm of insulation over the battens. Plastic as in plastic pipework (not copper)
Cold bridging won't be a big deal on tiles (they get wet anyway), on the other walls you might get condensation on the wall surface above the battens. Again not a trauma if you've got (and use) ventilation in there but one to be aware of next time
EDIT If you're plasterboarding in there you could use Marmox board instead- its about the same R value as polystyrene so 12.5mm won't do much but its better than nowt

 

[jamie765]

There's ventilation in terms of trickle vents in windows, and will be an extractor fan in the bathroom, if that counts.

I've already purchased moisture plasterboard for the bathroom which I can't return as I cut in halves to fit them up the stairs.

Wish I knew about the marmox board earlier though, think I probably would have gone for that all round in the bathroom, rather than 12mm hardibacker on the shower walls and moisture resistant plasterboard on the rest of the bathroom walls.

Would the vapour barrier sheet make a difference then?