FD30 or FD60 for a loft conversion? How do you actually work out which rating you need?

In a loft conversion it'll almost certainly be FD30, which is what Approved Document B requires for doors opening onto the escape route when you've got a new storey. Nine doors to habitable rooms off the stair all get FD30s, self-closing. That said, the answer isn't the builder's off the top of his head - it's your building control officer. They've approved the plans, so ring them or email and ask them to confirm the rating in writing before you order. Takes five minutes and kills any arguement later. If your plans say 'fire doors' without a rating, most BC offices will just confirm FD30 when you ask, but get it from them, not the bloke on site.

On the looks side, you're fine. Fire doors come in exactly the same oak veneers, glazed options and painted finishes as normal internal doors these days. The give-away is the thickness - an FD30 is usually 44mm against the 35mm or 40mm of a standard door - so the frame and stops need to suit that. Some people notice the extra weight when you swing them, but visually you can match an oak internal door no problem. Just check the spec sheet says FD30 and it's from a proper certified range, not a manufacturer bolting the rating onto a picture of something else. Checking them when they turn up: look on the top edge or the hanging edge of the leaf for a certification plug or label. It's a small plastic or foil tag with the manufacturer's mark, the certifier's logo like BM Trada Q-Mark or Certifire, and the rating printed on it. FD30 will say FD30 or sometimes 30 minutes. No plug or label, no rating, simple as - reject it. While you're at it, check they've come with intumescent and smoke seals in the leaf edge or the frame, and that the ironmongery you buy (hinges especially) is CE marked and fire rated, because a rated door hung on the wrong hinges loses its rating.

Order with the BC confirmation in hand and you can't go far wrong.

Not buying the 'visually you can match any oak internal door no problem' line from the reply above. In practice the fire rated ranges are a fraction the size of the normal ones. I did the same hunt for our place and there were maybe a handful of oak-faced options in the sizes I needed, and nothing close to the flush style we wanted upstairs. The pictures look great but you get to a supplier and half of it is special order with a lead time. Ask to see the actual door, not a sample, before committing to nine of them.

One thing to watch when ordering: the rating applies to the whole assembly, not just the leaf. When I did the replacements on our landing I bought some decent FD30 leaves then tried to reuse the old frames, and the supplier wouldn't sign off it. Ended up getting the doors and frames as certified sets from the same range, wich cost more but meant the tags on the door and the frame actually matched each other. Also worth phoning your joiner before ordering, because a 44mm leaf in an existing 35mm rebate means planing the stops down or buying new linings anyway, better to know before the pallet turns up.

Agree with the fella who said get the full sets, same thing happened to us. Ordered the leaves thinking our existing linings would do, then the fitter pointed out the FD30s are chunkier so the stops and the rebate all needed sorting anyway. We went back and bought the pre-hung sets with the frame and seals allready fitted, made the install dead simple and everything had matching tags on it. Only other thing I'd say is budget for the self-closers, ours came with them included which saved a second order.

Worth thinking about the self-closing bit too, cos that's what your wife will actually clock day to day, not the finish. A closer on a heavy 44mm leaf can feel pretty clunky and slammy unless you go for a decent soft-close one. We swapped ours to concealed closers fitted into the door edge and you barely notice them now. Ask the supplier which ranges work with those before ordering. Also check the tags the day the doors land, not when the joiner's already hanging them. We had one arrive with the foil label scuffed off the edge and sorting a replacement set us back nearly a fortnight.