Solve backwards
How much wall will my mineral wool boards insulate?
- 200 boardsThe example worked below
- Exterior Mineral Wool Board Insulation CalculatorEvery figure is its own
You have
How much mineral wool board?
Worked by the Exterior Mineral Wool Board Insulation Calculator at the settings below.
The settings it uses
- Board Length
- 48 in
- Board Width
- 24 in
- Number of Layers
- 1
- Waste Factor (%)
- 10
What it will do
1,455 sq ft of wall
135 m²
One house. Enough for the walls of a house about 45 × 45 ft with 8 ft walls.
Or several. About 3 houses of the size the Exterior Mineral Wool Board Insulation Calculator opens on: the walls of a house about 13.4 × 13.4 ft with 8 ft walls.
Check it forwards
- Area to Insulate
- 1,455 sq ft
- It asks for
- 200 boards
- You have
- 200 boards
The Exterior Mineral Wool Board Insulation Calculator asks for 200 boards at that size, and 201 boards one step larger.
If you had more, or less
Around your amount
Each worked by the Exterior Mineral Wool Board Insulation Calculator at the same settings.
Half
100 boards
727 sq ft
the walls of a house about 22.7 × 22.7 ft with 8 ft walls
Yours
200 boards
1,455 sq ft
the walls of a house about 45 × 45 ft with 8 ft walls
Half as much again
300 boards
2,182 sq ft
the walls of a house about 68 × 68 ft with 8 ft walls
Double
400 boards
2,909 sq ft
the walls of a house about 91 × 91 ft with 8 ft walls
Common amounts
What each amount of mineral wool board covers
The sizes it is usually sold in, each worked by the Exterior Mineral Wool Board Insulation Calculator at the settings above.
| You have | It covers | As one house | Average houses |
|---|---|---|---|
| 50 boards | 364 sq ft(33.8 m²) | the walls of a house about 11.4 × 11.4 ft with 8 ft walls | under 1 |
| 100 boards | 727 sq ft(67.6 m²) | the walls of a house about 22.7 × 22.7 ft with 8 ft walls | 1 |
| 200 boards | 1,455 sq ft(135 m²) | the walls of a house about 45 × 45 ft with 8 ft walls | 3 |
| 300 boards | 2,182 sq ft(203 m²) | the walls of a house about 68 × 68 ft with 8 ft walls | 5 |
No single standard board
Unlike rigid foam, semi-rigid mineral wool board has no one market face size, and sizes differ between density grades from the same maker, so take both dimensions off the pack. A 48 by 24 inch board is 8 square feet and covers about 7.3 after the ten per cent; a 1200 by 600 mm board is 0.72 m² and covers about 0.65. Two hundred boards wrap about 1,455 square feet, or 131 m² of the metric board.
Every layer is a full order
Two thinner layers with staggered joints outperform one thick layer of the same total depth, because the joints in one layer are covered by the body of the other. Each layer is a full-area order — the offcuts from one cannot make up the next, since staggering is what stops their joints lining up — so a two-layer wall halves the answer here. Deduct openings rather than leaving them in as a margin.
Thickness is the real decision
This counts boards, not a thickness, and thickness matters most on an exterior wall: the board has to keep the sheathing behind it above the dew point of indoor air reaching it, and a layer too thin can leave the wall wetter than none at all. Fixings are not counted — mineral wool compresses, and over-driving dishes the board — nor are furring, Z-girts, membranes, reveals or flashing at heads and sills.
How the answer is worked
Nothing here is a second formula. The Exterior Mineral Wool Board Insulation Calculator runs forwards — a size in, a quantity out — and this page grows its own starting house in proportion until the quantity it asks for is what you have. Where it rounds up to whole containers, the answer is the largest size before the next one would be needed.
Where the calculator adds an allowance for cuts or breakage when you order, the same allowance comes off here, because it is the same calculator: a stack you already own finishes less than its face value. Where it adds none, neither does this page — the settings beside the answer say which.
Exterior Mineral Wool Board Insulation Calculator
runs it forwardsCount semi-rigid mineral wool boards for continuous exterior insulation, including multi-layer build-ups with staggered joints.
Work out what to buy insteadSolve backwards
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Solve backwards
Start from what is already in the yard
Paint, sheets, rolls, bags and pieces, each read the other way by the calculator that orders it.
The calculator's own figures
Nothing is estimated twice: the page runs the same calculator you would order with.
The largest size that fits
Where a calculator rounds up to whole containers, the answer stops before the next one.
Both unit systems
Gallons and litres, square feet and square metres, side by side.
Frequently asked questions
- How much wall does 200 boards of mineral wool board cover?
- At the Exterior Mineral Wool Board Insulation Calculator's own settings, 1,455 sq ft (135 m²) — the walls of a house about 45 × 45 ft with 8 ft walls. That is about 3 houses of the size the calculator opens on: the walls of a house about 13.4 × 13.4 ft with 8 ft walls. Every figure follows the settings, which you can change in the calculator.
- How many square feet are in a board of mineral wool?
- It depends on the product; there is no single standard face size. A 48 by 24 inch board is 8 square feet (0.74 m²) and a 1200 by 600 mm board 0.72 m² (7.75 square feet). With the calculator's ten per cent for cutting, those cover about 7.3 square feet and 0.65 m² of wall each.
- How many mineral wool boards for 1,000 square feet of wall?
- At 48 by 24 inches, 1,000 square feet (93 m²) plus ten per cent is 1,100 square feet, or 138 boards (137.5 rounded up) in one layer; a second layer doubles it. In metric, 100 m² plus ten per cent is 110 m², or 153 boards of 1200 by 600 mm.
- Is exterior mineral wool better in one layer or two?
- The calculator's guidance is that two thinner layers with staggered joints outperform one thick layer of the same depth, because each layer's joints are covered by the other's boards. Each layer is ordered on the full area, and the total thickness is a moisture decision for the climate, not a board count.