Expanding foam to fill a gap in a new ceiling

[dennij]

Hi

I have had a new ceiling fitted (plasterboard) but this was cut short of an edge by the staircase, I would say that the gap is around 7cm x 47cm This was mentioned to the builder who was going to rectify the issue. On my last visit to the propery I notice that the gap has been filled with expanding foam and a bonding coat has been applied but some of the expanding foam can still be seen through this bonding coat. The builder tells me this is acceptable practice and that the expanding foam is fire resistant. Knowing that the foam will never be a solid surface I'm wondering if this would be acceptable for any plasterers out there as I now has 3 different surfaces, plasterboard, foam and wood that I'm sure will move at different rates and therefore may cause the finish plaster to continually crack.

Any thoughts please?

[wine~o]

Sounds like a bodge to me. Pics ?

[steviejoiner74]

We use it to fill small cable holes or gaps but usually up to a maximum of 10-15mm

[dennij]

I have managed to fins a before and after photo which I hope will help

Gap on new ceiling before fill with foam

Pre Fill.jpg (612.39 KiB) Viewed 3142 times

After foam added and bonding coat applied

Post Fill.jpg (347.17 KiB) Viewed 3142 times

[Job and Knock]

The builder tells me this is acceptable practice and that the expanding foam is fire resistant.

Interesting! Was it pink AFFF foam and was it applied in accordance with the manufacturer's instructions (normally to fill a gap of no more than 10mm and with a 10mm layer of intumescent applied on top between the foam and any covering materials)? If not then it isn't fire resistant according to CertFire, etc. - most expanding foams are as flamable as timber. So, just where did he tie up his horse whilst working in the house?

[dennij]

Can't say I've noticed any pink anywhere but the gap exceeds the 10mm you mention that's for sure. I suspect then that it's going to be as fireproof as paper and right by the staircase too. Best thing I can do is get a competent person in to do the ceiling again but properly this time.