762mm fire doors (78" x 30")
762mm is the most common fire door width in UK homes, matching the standard internal door size at 78" x 30". The critical difference is that a fire door has a very small trimming allowance. Cutting one down to fit an awkward opening can end its certification entirely.
On a standard internal door, buying slightly big and trimming to fit is normal practice. On a fire door it is the single most common way an installation is quietly invalidated, and nothing about the finished job looks wrong afterwards.
This page is mostly about that difference, because it is the one thing that changes when the same 762mm width carries a rating.
Showing 1 door
Prices are guide prices including VAT, taken from the smallest size and plainest finish of each door. They are not an offer to sell — confirm the price for your size and finish before ordering.
No doors match these filters yet. Clear a filter to widen the search.
One door in the catalogue matches this right now. The range is still being built out, so this listing will grow.
Fire doors have almost no trimming allowance
A fire door was tested at a specific size with a specific core, and the manufacturer states how much may be removed from each edge. The allowance is typically far smaller than on a standard internal door, and on some doors it is nil on the top and bottom.
Exceeding it does not merely void a guarantee. It removes the evidence that the door performs for 30 minutes, which is the only reason it is in that opening. [VERIFY: the trimming allowance printed in the instructions supplied with the specific door] — never assume it from another product.
The gaps around the leaf are specified, not chosen
On an ordinary door the gap around the leaf is a matter of taste and season. On a fire door it is part of the tested assembly, because the intumescent seal is sized to close a particular gap when it expands.
Too tight and the door binds; too wide and the seal cannot bridge it. The threshold gap is specified separately again, and it changes depending on whether there is a floor covering under the door. Take all of these from the manufacturer’s installation instructions rather than from habit.
If the opening is not 762mm
Adjust the opening, not the door. Lining out a slightly oversized opening with correctly fixed timber is the normal route, and it keeps the leaf exactly as it was tested. Packing behind the lining has to be done properly, because the fixings are part of how the assembly holds together under heat.
If the opening is smaller than 762mm, drop to the next fire door size down rather than cutting a 762mm leaf to fit. There is a reason fire doors are sold in the same size ladder as everything else.