Internal insulation

[Benn212]

I am currently installing Kingspan to the underside of an existing plasterboard ceiling. The property is an old barn, the room a bedroom with exposed beams, The insulation sitting between the beams ready to plasterboard and skim to create a new ceiling and warmer room. I have fitted battens to the beams to create a parallel space for the Kingspan. As non of the beams have straight edges this has left a considerable space between the beam and batten. My question is what do I need to fill the space with? I have considered expanding foam but this is messy stuff and will need to be sprayed upwards, and should I have left an air gap between the Kingspan and existing plasterboard?
Thanks

 

[geraldthehamster]

I am currently installing Kingspan to the underside of an existing plasterboard ceiling. The property is an old barn, the room a bedroom with exposed beams, The insulation sitting between the beams ready to plasterboard and skim to create a new ceiling and warmer room. I have fitted battens to the beams to create a parallel space for the Kingspan. As non of the beams have straight edges this has left a considerable space between the beam and batten. My question is what do I need to fill the space with? I have considered expanding foam but this is messy stuff and will need to be sprayed upwards, and should I have left an air gap between the Kingspan and existing plasterboard?
Thanks

Is the new plasterboard going between the "beams", attached to the battens and leaving the bottom part of the beams showing, or are you just plasterboarding over the lot?

Cheers
Richard

 

[Benn212]

Yes, leaving bottom half of beams exposed. Thanks

 

[RickyLee53]

Yes, leaving bottom half of beams exposed. Thanks

When I did similar I used expanding foam, but I wasn't keeping the beams exposed so it didn't matter if I got it on them. And your right it made a mess.

The other option is normal insulation packed in there... But this will make a mess of your arms.

How big are the gaps?

 

[Benn212]

Some of the gaps are pretty minute and I can probably fill them with some caulk -but not sure of the insulation value of this stuff, big gaps are at least 250mls, will probably fill with bits of sliced kingspan if no other ideas are forthcoming but its a lengthy process and not very efficient nor does it quite fill the undulating gaps in the beams but I can't think of anything else.
Thanks guys.

 

[geraldthehamster]

Yes, leaving bottom half of beams exposed. Thanks

How big are the gaps between the beams and the battens? If they are up to about half an inch, you could use expanding foam successfully without getting it everywhere. Get a proper gun, rather than using the cans with their own nozzles. You can adjust the flow so that the foam wedges itself in there and (mostly) doesn't fall out. When it's gone off, trim it flush to the front of the batten with a breadknife.

If your gaps are bigger than that, then personally I'd just stuff them with rockwool insulation.

Then fix plasterboard to the battens, and skim to the edges of the beams.

Cheers
Richard

 

[voicey]

Do you have enough space above to fit plasterboard between two beams and then reach over the top from the side and fill in the gaps with expanding foam? Obvisouly you'd need to use something else for the last row....

 

[Benn212]

Thanks for the advice that's really useful - I didn't know therre was a proper gun for the expanding foam so will try that - will have to see how it goes spraying upside down! May end up using rock wool bot it's expensive to buy a full roll just to fill some gaps. Thanks

 

[geraldthehamster]

Thanks for the advice that's really useful - I didn't know therre was a proper gun for the expanding foam so will try that - will have to see how it goes spraying upside down! May end up using rock wool bot it's expensive to buy a full roll just to fill some gaps. Thanks

I've used a foam gun to seal round the edges of Kingspan between rafters. You need to set the gun to a low setting, to squirt a bead narrow enough to go into the gap, that sticks to the edges. The nozzle of a gun is much finer than the end of the plastic tube that comes with a dipsosable can. If you have a quantity to do, it's much less unpleasant with a proper gun.

Edited to say that to use a gun or a disposable, the canister has to be more or less upright and inverted, so you'll use it with the nozzle pointing up at an angle, rather than "upside down" as such.


Richard