Suitable material for kitchen/stairs partition

[norb]

My stairs cut diagonally down through my kitchen and are currently partitioned by a single thickness of plasterboard which has small tiles on it (in the kitchen). It amounts to a triangle about 6 x 6 feet on the short sides. The tiles obviously stiffen the partition but the whole thing is bowed, possibly due to weight of those tiles, so has to come out.

Plasterboard seems to be an inappropriate material for this job as a single thickness would be unsupported except around the three edges of the partition. I don't want to tile the kitchen side either. There would be insufficient space to construct a double skin stud wall partition due to a kitchen door frame.

Is there a way to strengthen plasterboard in an application like this ? Would fire-retardant mdf (red) be a better choice and is it fire-retardant enough to go between the kitchen and stairs? Would two thicknesses of 9.5mm plaster board glued together be strong enough without any support except at the edges of the triangle ?

 

[Fred61]

Well you ask lots. So fire, unless the rest if the area is fire proof or is being up graded I would forget this. As I’m sure for a start the kitchen ceiling won’t be fire proof. As for a suitable replacement I would build the wall out of 12mm ply this is a very stable material at that size I would bond two sheets together. But do this in place as you can then make sure you overlay the joint. This will give you a very stable wall and will also give around 20 minuets of fire protection. Which is about the same as most ceilings and normal internal doors. Fred.

 

[endecotp]

So fire, unless the rest if the area is fire proof or is being up graded I would forget this. As I’m sure for a start the kitchen ceiling won’t be fire proof.

If the only escape route from your upstairs bedrooms is down these stairs and through the kitchen, then fire safety should certainly be a concern! (I would expect the kitchen ceiling to be plasterboard, and hence fireproof, though it sounds like flames can simply go straight up the stairs...)

As for a suitable replacement I would build the wall out of 12mm ply

Yes, I'd also go for ply. Or conceivably OSB if you're on a tight budget. The thicker it is the less support you need behind to make it rigid.

 

[Fred61]

Yea I’m no lover of osb as it can fall to bits as soon as look at it. By using two thin ply you can overlay the joint. You will end up with a very stable wall at 24mm thick. Fire is always a concern and we regularly talk to building control about the needs of a particular site. I would recommend linking all your smoke detectors to giving you the best early warning. Also make sure you have escape hinges on your upstairs windows. There are many thousands of houses that don’t have these so you can’t climb out if you need to. Fred.

 

[^woody^]

12.5mm plasterboard and skim is used as standard with no problems.

 

[norb]

Wow, thank you all for your reasoned advice! Lots of food for thought there from all.

unless the rest if the area is fire proof

Its probably as good as most buildings of this era but I want to at least improve it if possible.

the kitchen ceiling won’t be fire proof

I'm hoping that having had it overboarded and reskimmed it will be better than the original board and artex.

This will give you a very stable wall and will also give around 20 minuets

That sounds about what I would expect to need.

If the only escape route from your upstairs bedrooms is down these stairs and through the kitchen, then fire safety should certainly be a concern

It's the main route out down to the hallway and front door hence I want it as protected as possible. I will put a fire resistent door in the door frame, and add new plasterboard to the underside of the stair-case.

...we regularly talk to building control about the needs of a particular site.
Also make sure you have escape hinges on your upstairs windows. There are many thousands of houses that don’t have these so you can’t climb out if you need to. Fred.

Yes I could try talking to them informally and I don't have escape hinges so that's another good call.

 

[pilsbury]

As for a suitable replacement I would build the wall out of 12mm ply this is a very stable material at that size I would bond two sheets together..

Why not buy 25mm ply?

 

[norb]

This thread is old now but thought I would update with what I actually did in case others find it useful. I used red fireboard (plasterboard not mdf) in the kitchen and to aid the fixing and add impact strength I used an overlapping sheet of 9mm ply on the stairway side cemented to the fireboard. Fireboard was found at Wickes at about 9 quid a sheet I think. Fireboard was also used to replace the plasterboard on the underside of the staircase. This material is denser than regular plasterboard and manhandling it to any overhead position is harder than the lighter standard plasterboard but I would now be inclined to use this anywhere extra fire protection is wanted.