I am a maintenance operative at a secure mental health facility. Following on from attending a fire Marshall course the fire door inspections have now had many failers. These are mainly due to excess gaps around the doors, and damage to the leading edges. I have seen Envirograf products for replacement and intumescent strip. But would it be possible to trim the door and install a strip of hardwood, rebated for intumescent strip. This would allow for the extra needed to fill the excessspace, and would be much more cost effective. We also have some doors with the closer rebated into the top of the door. Some of these have upto 10mm gaps above the door. We can install an extra door stop on the head of the frame, and would it comply if we were to fit a smoke seal to that. Such as the ones listed by Envirograf for example.

Thank you

Would need to see the doors in question. Fire doors vary (according to their construction) in the type of closer that's acceptable and to what degree the edges may be trimmed to fit replacement lippings.  Clearly, you are attempting to improve on the current likely level of fire & smoke performance of the fire doors but it would be wise to engage a fire door inspector, they can report on what type of remedial work can be done.