Sealing edges of garage ceiling

[sb55]

I have an attached garage, which is part of an extension that was built in 2003.

It is unheated but usually stays at least 5c above the outdoor temperature.

The ceiling is plaster-boarded and artexed, but there is a gap around the edges, between the plasterboard and wall. It varies in width but is around 7mm in most places.



As it was left like that I presume that there is no problem, however I wondered if it is OK to seal around the edges?

The reason for this is that I have placed a freezer in the garage, and while the fire risk is low, I would not want smoke making its way to the habitable room above.

A solution I found would be intumescent sealant, but I am concerned that the gaps may be required for ventilation above the plasterboard. I would not want any damp there. When I shine I torch up through the gap I see more block, so there is definitely nothing there, at least up to the wall.

Any comments or input would be appreciated.

 

[Tigercubrider]

No expert but I don't see an issue.
My garage is under a bedroom which extends between above the hall and garage.
The garage is plasterboarded on the ceiling edge to edge but bare brick.

Is there a bit of timber between the wall and plasterboard? I might be tempted to poke a bit of coathanger wire up the gap and see if there is? If so, you could buy a £7 bag of plaster and mix it in a bucket, using a filling knife to fill between the wall and ceiling. Working along the garage?

Even gripfill would work. That comes in a tube for easy (ish) application.

 

[foxhole]

Fire rated foam for quick and easy fix.