UK metric modular
200.0 × 75.0 × 100.0 mm
7 7/8 × 2.95 × 3.94 in · format 210.0 × 85.0 mm · 57 per m² · United Kingdom
About this unit
A rarely used alternative sized so that the format is a round 210 × 85. It never displaced the 215 standard, and mixing the two in one wall does not course.
The size that matters is the format
A brick is never laid on its own. Add one 10.0 mm joint and the working unit becomes 210.0 × 85.0 mm, and every dimension in the wall is a multiple of that rather than of the brick.
| Actual size | 200.0 × 75.0 × 100.0 mm |
| Mortar joint | 10.0 mm |
| Format size | 210.0 × 85.0 mm |
| Per square metre, single skin | 56.02 — order 59 with 5% waste |
| Courses per metre of height | 11.76 |
| Units per metre of length | 4.76 |
Setting out
Ten courses rise 850 mm and ten units run 2100 mm. Openings, sills and damp courses are placed on those multiples wherever possible, because a wall that has to be cut to reach a dimension costs labour and shows.
Other United Kingdom units
| Unit | Actual | Format | Per m² |
|---|---|---|---|
| UK standard brick | 215 × 65 × 103 mm | 225.0 × 75.0 | 59.3 |
| UK imperial brick | 228 × 68 × 108 mm | 238.0 × 78.0 | 53.9 |
| UK concrete block | 440 × 215 × 100 mm | 450.0 × 225.0 | 9.9 |
Frequently asked questions
What size is a uk metric modular?
200.0 × 75.0 × 100.0 mm (7 7/8 × 2.95 × 3.94 in). Add the 10.0 mm joint and the working size — the format — is 210.0 × 85.0 mm.
How many bricks per square metre?
56.0 for a single skin — 57 in practice, before allowing for breakage. That comes straight from the format: 1,000,000 mm² ÷ (210.0 × 85.0) = 56.02.
How many courses per metre of height?
11.76 courses, at 85.0 mm each. Setting out from a fixed course height is why a window head or a damp course lands where it does rather than where a drawing might prefer.
Why does the joint matter so much?
Because the brick on its own is never the unit of construction. Masonry is set out on the format size — one unit plus one joint — and every dimension in a wall is a multiple of it. A 75.0 mm brick with a 10.0 mm bed rises 85.0 mm per course, and that 85.0 is the number the wall is actually built from.