Skirting cannot be joined invisibly halfway along a wall, so each wall has to be covered by whole lengths. Divide the total run by the stock length and you will be short — usually by one.
Enter the room and the longest length your supplier carries. We count wall by wall, because that is how it actually gets cut.
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Skirting cannot be joined invisibly halfway along a wall, so each wall has to be covered by whole lengths. Divide the total run by the stock length and you will be short. A 4 × 3 m room has 14 m of wall; from 3 m stock lengths, division says five lengths, but counting wall by wall — two lengths for each 4 m wall, one for each 3 m wall — gives six. That is the trip back to the yard that this page exists to prevent.
Scribing one piece over the profile of the other survives the timber moving. A mitred internal corner opens up within a year and no amount of filler holds it closed. External corners are mitred, and mitre waste is real — every external corner eats a little more than the wall length suggests, because the cut runs at 45° through the thickness. Buy one extra length, because the first scribe is usually the practice one and a bad cut on the longest wall is expensive.
Or at least account for it. Skirting normally sits on the finished floor; fit it to the subfloor and then lay flooring under it and you leave a gap you will have to hide with beading. Check the walls before you buy too — bowed walls need either packing behind the skirting or a scribe along the bottom, and both take longer than the fixing itself. Architrave is a separate calculation, at roughly 5 m / 16 ft per standard door opening plus mitre waste.
Count wall by wall rather than dividing the total perimeter by the stock length. Skirting cannot be joined invisibly mid-wall, so each wall needs whole lengths — which usually means more than the division suggests.
Scribed. Scribing one piece over the profile of the other survives seasonal movement in the timber; a mitred internal corner opens up within a year and cannot be filled convincingly. External corners are mitred.
After, normally — skirting sits on the finished floor. Fitting it to the subfloor and laying flooring underneath leaves a gap that then needs beading to hide.
Roughly 5 m (16 ft) per standard opening, plus mitre waste. It is a separate calculation from the skirting.