Double boarding garage ceiling - edge detail

[garyo]

Hi

I'm double boarding the ceiling that separates my internal garage from the bedroom above. As per the approved plans I'm double boarding in 12.5mm with staggered joints.

How should I finish the edges where the boards meet the wall? In some cases I can get the boards tight up against the wall so there's limited scope for pink foaming or sealing in place, so I'm wondering whether I should leave then 5mm from the edge and then apply Intumescent Sealant or pink foam?

Thanks

 

[^woody^]

Tight to the walls and the intumescent mastic after skimming. Not foam.

 

[garyo]

Tight to the walls and the intumescent mastic after skimming. Not foam.

Thanks. Is tape and joint as acceptable as skimming?

 

[^woody^]

I've never thought it would be, as then you then have the paper backing exposed to flame.

It might be best to check with British Gypsum, Knauf or Lafarge etc.

 

[garyo]

I'll have a look at their website.

I've never thought it would be, as then you then have the paper backing exposed to flame.

It might be best to check with British Gypsum, Knauf or Lafarge etc.

I'll have a better look when I'm not on a phone but it seems okay on the face of it :

The fire resistance and sound insulation performances are for imperforate partitions, walls and ceilings incorporating boards with all joints taped and
filled, or skimmed according to British Gypsum’s recommendations. The quoted performances are achieved only if British Gypsum and Saint-Gobain Isover
components are used throughout, and the Company’s fixing recommendations are strictly observed. Any variation in the specifications should be checked
with British Gypsum.
To establish the maximum cold state h