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How to fix gaps in fire door

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my apartment fire door has a gap of 12mm from the floor and I was thinking to use this https://www.safelincs.co.uk/surface-mounted-drop-down-smoke-seal/?q=seal

does that mean that once that is in place it's enough to be compliant? Or is it just a temporary solution? If it's not enough to be considered compliant how can I fix that?

Would a fire resistant threshold strip help? Not even sure it exists.


The gaps on the sides go between 1mm and 4mm is there anything that can be done there? I think it's because the door or the frame are not perfectly straight.


There is a small gap, 1 or 2 mm between the hinges and the end of the intumescent strip on the frame, should I add the missing piece? Or should I replace the entire strip? Is it something I could do on my own? Any suggestion on which one to buy?


Last question, I have seen intumescent pads that can be placed on top of the hinges, is that something worth buying?


Thank you for your help and patience.



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In terms of compliance, it depends on the circumstances.

For flat entrance doors in blocks over 11 metres storey height Government guidance can be found here:  https://www.gov.uk/government/publications/fire-safety-england-regulations-2022/fact-sheet-fire-doors-regulation-10

In terms of compliance with the relevant standard, BS 8214: 2016 Timber-based fire door assemblies - Code of practice you would need to consult the installation instructions for the fire door in question.  To answer your specific questions:

1) The 12mm threshold gap exceeds the usual requirement of 10mm for fire resistance performance and 3mm for restricted spread of cold smoke. You could install a threshold plate to the floor to reduce the gap under the door and a flexible seal to seal the gap for smoke purposes.

2) The gaps between the door leaf and door frame at the top and vertical edges should be between 2mm and 4mm. You could adjust the fit of the door leaf in its frame to achieve those gaps.

3) You could replace the intumescent strips to rectify the very small gap where they stop short of the hinges. Different intumescent strips can vary in the way they intumesce so its best practice to replace them as a set.  You will require cold smoke seals too. 

4) The intumescent pads fit behind the hinge blades between the hinge and the timber door and frame. In a severe fire they can act as a gasket to restrict the rate of char to the timber from the metal hinges. 

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Hi @Neil Ashdown MAFDI, first of all thank you, it's great you took the time for such a detailed response, which is incredibly helpful.

on 1) I was thinking to install this https://www.safelincs.co.uk/surface-mounted-drop-down-smoke-seal/?q=seal, hopefully this will fix the problem. I'm looking at threshold seals, do you think that would be better than the dropdown seal?

on 2) I have taken better measurements and the door is not straight, there is a section on one of the sides that is 5.5 mms. Too bad the other side is 3.5 mms, so even trying to adjust it, I would have more than 4mms on one side (just a small section). Is there anything that can be done in this situation? Would that framefit product I mentioned above be helpful? The installer mentioned that intumescent strips with taller brushes will fix this but I'm not sure.

on 3) ok I think I will replace these as a set, is it a job that anyone with some DIY skills can do or should I ask an expert?

on 4) sounds like I will skip these as they weren't installed and I would not be able to put back the door the correct way.

Thank you again!

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