Thanks Lin, though the gapfiller may be messy to apply and the doors will need to be wedged whlst it skins over to avoid contaminating the smoke seal. We also need to consider the smooth even surface required for correct operation of the smoke seal.
Not sure Lin was suggesting mastic, Kurnal - think she might have been suggesting a low-pressure gap-filling solid intumescent strip like Interdens... (
http://norseal.co.uk/browse/interdens/norseal-interdens - often used in glazing or behind hinges & locks).
Best solution (in my view) is what Wee B suggested - strips of the same timber used in the frame tightly fitted and glued using thermosetting adhesive. Not good practice to put intumescent strips opposite each other & whilst in the real world it might make no significant difference to fire safety the door and/or seal manufacturers would be unlikely to support an installation like that, which could cause issues during acceptance and hand-over.
