Question about cutting fire door casings

[jonmc1980]

I’m looking for some advice about assembling some fire door casings that I have bought. I was hoping someone could tell me the best way to assemble them. My doors are unusual sizes so I bought casings which haven’t been rebated. I have researched online and have found most of the advice I need apart from the best way to cut them to assemble correctly. I don’t want to mess it up so hopefully someone here can advise me. As I understand it I mark the head section where the jamb meets it and then cut to the rebate level and then screw to fix? I am a bit confused about the channel for the intumescent strips as this will continue through the head when I fix them together – is this usual or am I missing something? Thanks to anyone who can offer me advice!

View media item 64577

 

[pinenot]

If the picture posted is the ones you have bought, they are rebated. that said that shouldn't be much of a problem. You'll need the width of your door plus roughly 10mm for clearance both for the door and the intumescent strips, That's assuming they have smoke brushes incorporated in their makeup?

...pinenot

 

[jonmc1980]

Hi, sorry I don't think I explained that very well. I just wanted to know how to cut the header / jambs to assemble them in the correct manner. Am I correct in thinking that I cut a marked section out of the head on each side which the jambs insert into and then screw them in place?

 

[freddiemercurystwin]

Appreciate the OP may know this, but pinenutter, clearance should be about 2-3mm each side, brushes only required in non-domestic or if domestic three storeys or over.

 

[pinenot]

Hi, sorry I don't think I explained that very well. I just wanted to know how to cut the header / jambs to assemble them in the correct manner. Am I correct in thinking that I cut a marked section out of the head on each side which the jambs insert into and then screw them in place?

Yes just cut and pare away the waste then screw or nail them (they are captivated between the slap walls once installed) If you make sure they are straight and parallel (long straight edge) once fixed in, the door need only be hinged and hung in the usual way...pinenot