I have to say to the OP that having a veneered door which drags along the carpet is actually a bad idea - there is always a tendency for the edge of vertically orientated veneers to chip off at the door edge, particularly brittle veneers such as oak. This can be circumvented to an extent by planing a 2 to 3mm chamfer on the bottom edge of the door, but it sounds as though the OP would veto that
Ovetall I think I'm with
@Notch7 and
@chirpychippy on this one - pack the heads of the casings, infill the keep recesses and hinge recesses in the casing with Dutchmen (timber patch pieces), recut them, then move the architraves downwards (i.e. shorten the legs). A repair on (presumably ) painted softwood is easier to hide
@Diver Fred whilst I work in metric I have been on more than a few projects where either the cluent or the architect or the buyer has messed up when choosing doors and has made incorrect choices for door openings (because masons don't understand doors), frames and doors (because one was ordered as a metric size and the other as Imperial (but I will own up to a 6' 6" x 2' 6" door - or in metric a 1981 x 762 - being easier for me to remember in Imperial and then convert. Maybe it's my age...)
On the subject of lippings, 10 to 12mm is what DIY places sell, but I can certainly get English oak lippings up to about 30mm thick x 50 and 60mm wide ex-stock from a timber merchant in the next valley, and they will also machine down from thicker stuff to any size you want but as
@freddiemercurystwin has pointed out, if they are meant to be fire doors then relipping isn't allowed. The problem with this technique is that it always shows because of the grain orientation
Going the other way and chopping a bit off the top and sticking it on the bottom seems like a great way to go - to anyone who has never done it and is unaware of the pitfalls and problems which can occur with it. I have done it a number of times with flush doors (including recently converting three old flush solid core doors into two 8 x 2ft bifolding doors), but whilst you can sand your way out of trouble with flush doors which are to be painted, that isn't an option with wafer thin furniture veneered stuff. And that's before you take into account the saw cut kerf losses (2.2mm for each cut with a Festool saw, so taking 15mm off the top would give you 12.8mm on the bottom) and any other losses which might be incurred as a result of resquaring the doors if the carpenter needed to shoot the head in. A French polisher (or rather a "plastic surgeon") might be able to disguise the joint, if it were well executed, but I wouldn't bank 100% on that. I think that if it can't be hidden it would draw the eye to it every time. I do have to wonder if the person suggesting this has got real world experience of doing it (and if so could the share the technical details)
