Filling large gap between wall and fireboard

[JaniJohanson]

Hi Guys,

I've an integral garage with a bedroom above, and I've just boarded the ceiling of the garage with 2 overlapped layers of Gtec fireboard.

I'm after a little advice on filling gaps between the fireboard and the wall to create the best firestop I can.

For most of the perimeter the gap between the wall and the boards is < 5mm and I was intending on filling this with intumescent sealant. However on one side the wall isn't straight (where the boarding meets a steel beam which is already rendered over with plaster) - the gap goes from a few mm at one end to about an inch at the other.

I'm looking for advice on how to make fill this and maintain the firestop.

I've a couple of ideas; fill the gap with plaster or cut strips of the fireboard and put a "frame" round the edges of the wall.

Can anyone advise on a good way to go about this?

 

[23vc]

Fire rated expanding foam

 

[JaniJohanson]

I did see a can of that at the local merchants, messy stuff though.

There must be a better way.

 

[23vc]

Not really, squirt a load up there, trim off when dry, skim ceiling. Or even cut very thin slivers of board along that edge. But I’d say the foams the easier of the two.