Soudal Gap Filler in stairs to fix noise - worked but worried about fire

[HomeNoob]

Dear all,

Thanks for reading my post. In the process of redoing the flooring in my house (circa 1970s construction), the tradesman secured the stairs with screws, glue and brackets, which didn't do much. He then drilled holes into the stairs and filled the enclosed stairs undercavity with Soudal expanding foam - this worked brilliantly and the stairs are now perfectly silent.

My only concern is that the topmost 4 stairs are situated above the kitchen. The expanding foam is separted from the kitchen by means of a popcorn drywall. I have an induction cooker hob a good distance away, and a rice cooker and air fryer fairly close to the wall. The oven is located to the left of this drywall area.

I have attached an image to give you a rough idea of what I am taking about. The orange colour is where the foam is located. The oven is not in the picture, but would actually be coming out of the screen if it were 3D.

I am now concerned that this may be a fire risk. Would you agree, or would you not be worried about this? Does this go against any fire regulations? Many thanks for your time and expertise

 

[motorbiking]

Double plasterboard will provide 1 hour fire protection. You are right to be concerned as the stairs need to be protected as a means of escape. Rockwool is fire resistant, but the foam will not significantly increase the fire risk, though it is carcinogenic apparently.

 

[HomeNoob]

Thank you for the reply.

There are a couple of small holes in the plaster board. Will speckle do the trick for maintaining fire resistance?

Would you be concerned about the foam in that area - would you consider getting someone to remove it?

 

[motorbiking]

Why can’t you tack on a second layer of plasterboard? Each layer provides 30 minutes fire resistance and is a standard approach.