Adding up the room's perimeter and adding 10% gets you close, but it doesn't tell you which lengths to buy, and that's where the shortfalls come from. Plan each run into real lengths and you'll order the right amount, with fewer joints.
Skirting: measure each run
Measure every wall at floor level as its own run, including the returns of a chimney breast and any reveals. Stop the run at each doorway, where the skirting stops against the architrave (or a plinth block), and at anything built in, like fitted units.
Plan the runs into lengths
Skirting comes in set lengths, often around 2.4 m, 3 m or 4.2 m depending on the profile and the merchant. A 3.6 m wall needs a 4.2 m length (or a joint), not "3.6 metres", so plan each run against the lengths you can buy:
- Use one length per run wherever it fits, so there's no joint
- Where a run is longer than your longest length, plan a joint (a scarf joint hides best), ideally away from the eye line
- Use offcuts from long runs on short ones: a 600 offcut can do a chimney breast return
Allow a little extra on each run for scribing internal corners and mitring external ones, and keep a spare length for mistakes.
Architrave: per door, per side
Each side of a door needs two legs and a head. With the reveal (the small step back from the edge of the lining) and the architrave's width taken into account:
- Leg = lining height + reveal + architrave width (for the mitre at the top)
- Head = opening width + 2 × reveal + 2 × architrave width
For example, a lining 1981 mm high and 766 mm wide, with a 5 mm reveal and 69 mm architrave: each leg is 1981 + 5 + 69 = 2055 mm, and the head is 766 + 10 + 138 = 914 mm. So each side needs two lengths of at least 2.1 m and one of about 0.95 m (or one long length cut for the head and a leg). Both sides of the door: double it.
Many merchants sell architrave in door sets (two legs and a head), which are usually the simplest way to buy it.
Windows
Window architrave goes round three sides when the window has a board (sill) underneath, or all four sides when it doesn't. Work it out the same way as a door, with a bottom piece the same as the head when there are four sides.
Let JoinerKit work it out
In JoinerKit, skirting follows the walls you draw and stops at doors, fitted units and fireplaces, and architrave goes round each door and window you add. Both are cut from the lengths you buy, with the waste worked out, so you get the lengths to order and the cost, not just a length in metres.
Questions
What lengths does skirting come in?
Common lengths are around 2.4 m, 3 m and 4.2 m, but it varies with the profile and the merchant, so check what your supplier stocks before planning the runs.
How much extra skirting should I order?
Plan each wall run into the lengths you can buy rather than adding a percentage. Then allow a little for scribes and mitres, and keep one spare length for mistakes.
Do I need architrave on both sides of a door?
Usually, yes: an internal door has architrave on both faces of the wall, so each door needs two sets of two legs and a head.