Adapting an external door frame for a fire door

[dangti6]

This is a job I’ve been putting off, but it’s one of the very last things I need to sort for sign off.

 

I have an integral door ‘down’ in to my garage which is an old external door. To meet regs it needs to be changed for a 30 minute fire door.

 

As it steps down in, the exterior door frame with the sill is of benefit as it offers a threshold. In an ideal world I would like to be able switch the door and retain the frame to save interior decoration.

 

Therefore is it possible to adapt an exterior frame to take intumescent strips? There is a rebate already for a weather seal but it’s at the edge - would that rebate take a strip and meet the regs?

 

If not is it possible to add the strips to the door itself like in commercial applications - unsure whether the door thickness in such application and frame differ to the 44mm I’d be looking at.
 

 

 

The weather strip rebate I mention shown below 

 

Edited June 19, 2021 by dangti6

[dangti6]

More head in the sand time has passed and once again I have started to look at my options for replacing this door.

 

The existing door is 800mm wide, 1981mm tall and 45mm thick.

 

I understand the common 'standard' size of a door size is 1981 x 762 and the next size up appears to be 1981 x 838

 

Even if it was possible to adapt and reuse the existing frame, which I am now since starting to doubt being possible - 38mm of width is a lot to take off an 838mm wide door. At 19mm a side that's beyond the limits of what I have seen unless I find a solid door which is probably price prohibitive. 

 

813mm wide doors exist, but these are 2040mm tall and the same problem then moves to the material removable from the top and bottom of the door. 

 

1981 x 813 is what I really need, but that doesn't appear to exist from what I can see. Bespoke sizes are probably mental money unless anyone knows differently.

 

 

I believe my options to be as follows:

 

1) Buy a 762mm wide door which will be 38mm narrower than existing. Replace the frame and pack the frame out 19mm either side of my existing opening. Initial concern would be the internal decoration. Unless I used some much wider architrave to cover my sins, I would have to fill and patch the surround of the existing void. Not ideal and would rather avoid.

 

2) Buy an 838mm wide door. As I'd be cutting down either side I'd need to tidy up the inside and renew the architrave but there would be no void to fill. 

 

3) Keep trawling websites in the hope I can find a reasonably priced 838mm door that will allow ~19mm from either side to be taken off. If I do find one, can I reuse my frame or if I have to replace it, am I going to have a problem with adapting a frame to an opening of 800mm wide.

 

What would you do?

 

 

 

[Mr Punter]

You can router the door to take intumescent strips fairly easily.

[AliG]

You need a FD30 door blank. These can usually be reduced in size as much as you like.

 

https://www.builderdepot.co.uk/44mm-plywood-fd30-fire-door-blank-2135mm-x-915mm-7ft-x-3ft

 

Fire certificate

 

https://s3.eu-west-2.amazonaws.com/akeneomedia/PDFs/J000259/FD30_Half_Hour_Door_Blank_Certificate.pdf

 

However, you need to relip the cut edges.

 

Even cheaper

 

https://www.doorsuperstore.co.uk/product/hardwood-solid-core-unfinished-brazil-door-blank-lipped-fd30-1.html

[AliG]

If you don't want to do the cutting and lipping, you can get made to measure FD30 doors for around £200, just google bespoke FD30 doors and many companies who do this appear.

 

I am not sure how much work the lipping is and whether this is worth the extra £100ish.

[dangti6]

19 hours ago, AliG said:

If you don't want to do the cutting and lipping, you can get made to measure FD30 doors for around £200, just google bespoke FD30 doors and many companies who do this appear.

 

I am not sure how much work the lipping is and whether this is worth the extra £100ish.

 

Thanks Ali. Initially the lipping idea does put me off, plus I personally dislike the appearance of those plywood faced doors. 

 

If I sourced a nice looking bespoke 800mm wide door, I'm unsure if my existing frame would be suitable without certification.

 

This leans me towards going for an off the shelf 838mm door and frame Like this. 

 

Sill/threshold wise I assume I can reuse existing or replace with similar.

[AliG]

I am unsure about the frame issue. We have internal fire doors and they just have standard MDF frames, I have never been asked about the frames before and I feel that BC is mainly concerned re the doors and seals.

 

I do think replacing the frame also is the best idea. I suspect that the only thing that makes those fire door frames is that they are pre routed for the intumescent strips. 

 

The ply doors are simply the very cheapest option if you want to keep the price down, nicer doors and frames equals more cash, just depends on what you want to spend.

 

If you replace the frame with a narrower frame, it might be possible to get an opening that is either wide enough for a 838mm for to fit, or say get it to 826mm which you can probably achieve by cutting 6mm off each side of a 838mm fire door. Different doors seem to allow between 3 and 9mm to be cut off each side. It might indeed be cheaper to have a new frame and standard door as well as look neater once it is done.

 

 

 

 

[Bitpipe]

8 minutes ago, AliG said:

I am unsure about the frame issue. We have internal fire doors and they just have standard MDF frames, I have never been asked about the frames before and I feel that BC is mainly concerned re the doors and seals.

 

I do think replacing the frame also is the best idea. I suspect that the only thing that makes those fire door frames is that they are pre routed for the intumescent strips. 

 

The ply doors are simply the very cheapest option if you want to keep the price down, nicer doors and frames equals more cash, just depends on what you want to spend.

 

If you replace the frame with a narrower frame, it might be possible to get an opening that is either wide enough for a 838mm for to fit, or say get it to 826mm which you can probably achieve by cutting 6mm off each side of a 838mm fire door. Different doors seem to allow between 3 and 9mm to be cut off each side. It might indeed be cheaper to have a new frame and standard door as well as look neater once it is done.

 

 

 

 

As i remember, the only difference between a FD30 door lining and standard is that the FD30 is pre-routed for the intumescent strip, which you buy separately.

 

When we built we could not get enough FD linings so adapted some standard ones. You also need the fire stop (https://www.howdens.com/hardware/screws-and-ironmongery/door-furniture/door-stops/2mm-x-21m-redwood-fire-check-door-stop-obj-sku-family-mod0064).

 

 

[dangti6]

In the end I ordered an off the shelf 838mm wide door. Unavailable until mid September at the earliest, no doubt due to timber availability or whatnot. New frame to suit.

 

I am now sourcing some intumescent seals. As my garage is integral and largely uninsulated I am thinking about going for some 'fire and smoke' seals in the hope that the brushes may assist with some draught proofing. 

 

Oh, and a concealed door closer within the frame but can't put my finger on one that holds open. Any suggestions on alternatives that don't look horrendously industrial?

 

Next - to look at handles and locking/security arrangements ?  

Edited August 25, 2021 by dangti6