Fireproof door confusion

[brianivor]

I am planning to put a door through a 9inch solid internal wall into an integral garage thus I will require a 30 min fire door and frame.

Life would be a lot sweeter if I could have a door to my sizes rather than a "stock" size (mainly so its height would fit just under a course of bricks)

Where I am confused is that I have read that you can only shave about
4 - 5 mil off the fire door, which would appear to prevent me cutting down a standard size fire door.

I would have thought that a fire door was a fire door over its whole area regardless of its size - so does this restriction refer just to the final gap between the door and the frame or does trimming the door take it outside the fire regulations?

I have read the appropriate fire regulations concerning fire doors on the internet, but this point doesn't seem to be covered clearly.

I would be grateful for any advice, please.

 

[^woody^]

The point of specifying such a small reduction potential of fire doors is due to their construction of a central core and frame, and if you reduce the frame you can get delamination of the cover plywood at the edges or premature burning of the edge frame

It depends on the door make as to how much you can shave off

But you can also get larger sized doors, although these may not be stock items at most places

 

[freddiemercurystwin]

What size and style of fire door do you need?

 

[brianivor]

My ideal dimensions would be a notional 600mm door (just sufficient for domestic appliance clearance and withg a height to accomodate the distance from the floor to the underside of the most convenient brick course of 1035mm ie a 1000mm door.

Most standard doors are a lot wider and taller I find.

 

[brianivor]

Sorry, I mean 2035mm (2000mm door)

 

[^woody^]

height to accomodate the distance from the floor to the underside of the most convenient brick course of 1035mm ie a 1000mm door.

Do you live in the The Shires?

In any case, why you do you want a door to suit brick courses when the frame will be in between?

 

[freddiemercurystwin]

Just buy a fire door blank and cut it down to suit.

 

[brianivor]

No - I live in south Essex; for my sins.

The reason for the sizes - height mainly, is that a hole cut in the wall up to a suitable brick course is 2035mm hence the door required being 2035 less 35mm (frame) = 2000mm

In my ignorance I thought that it would be better than reinserting a partial brick course above the lintel if I could get the right sized frame - I also wanted to avoid if possible the expense of a custom made door.

Regarding the planing down of the door, I thought that the door would have been a solid door not a wood framework and wood panels either side.

 

[freddiemercurystwin]

Fire doors are tested and certified as they are manufactured. Once they are cut down they are no longer compliant as the certification is void. The only fire doors you can trim down are fire door blanks which are, in essence, solid. Eg http://www.wood-floor.co.uk/internaldoors/firedoors/firedoor-blanks.html

 

[joinerjohn]

Nothing wrong with putting a standard height fire door in then filling in above the frame though. Even a partial brick infill above the frame will be more fire resistant than the firedoor itself.
Most fire doors are constructed using either a chipboard type core, surrounded by a solid wood frame and covered on both sides with a ply type laminated cover, or something like a contiboard core, surrounded by a solid wood frame covered on both sides by a ply type laminate. Some 1 hr firedoors also have something like a plasterboard infill within the wooden frame.

 

[ajrobb]

Useful link, what does "lippings must be replaced and bonded in the correct manner" actually entail? Is it DIY or are we talking specialists?

 

[freddiemercurystwin]

You need to get some suitable lippings and replace them where they've been lost as part of the door reduction process. Something like min 6mm thick in a hardwood of a minimum density bonded to the door with a suitable fire resistant adhesive. Phone the suppliers and ask them to supply the lippings. There are other suppliers Howdens for one.

I suppose the OP could see if his building control would accept an intumescent coating to a non-fire rated door.

As mentioned though probably a whole lot easier to just replace the frame using a standard fire door.