Loft Boarding Calculator
Calculate how many loft boards you need for your loft. Enter the length and width of your boarding area, choose an Armstrong loft board or flooring kit, and get an estimated number of boards and packs including a waste allowance.
How Many Loft Boards Do I Need?
Use our free loft boarding calculator to estimate the boards or packs required for your loft floor.
How Many Loft Boards Do I Need?
The number of loft boards required depends on the size of the area you want to board and the size and coverage of the loft boards you choose. The simplest calculation is the loft area divided by the coverage of one board or pack, followed by an allowance for waste.
Armstrong Cheshire currently supplies loft flooring options including Akor chipboard loft boards, Akor OSB tongue and groove loft boards and complete Arranwood loft boarding kits containing flooring and loft legs. :contentReference[oaicite:3]{index=3}
Measure the loft area
Measure the length and width of the area you intend to board. For an irregular shaped loft, split the space into smaller rectangles and add the areas together.
Allow for unboarded areas
If part of the loft will remain unboarded, subtract that area from the total. This could include areas around a chimney, water tank, access point or sections reserved for other purposes.
Check board coverage
Different loft boards cover different areas. For example, Armstrong's Akor chipboard loft board pack contains three 1220 × 320mm boards and is stated to cover 1.17m². :contentReference[oaicite:4]{index=4}
Allow for waste
Cutting around the loft hatch, roof structure, chimney breasts and other obstructions can create waste. A 10% allowance is a useful starting point for estimating.
Loft Board Coverage Matters
Board dimensions alone do not always tell you the exact amount of usable flooring you will get. Tongue and groove boards interlock, and the manufacturer's stated coverage is therefore the most useful figure when calculating how many packs to order.
Armstrong's Akor chipboard loft board packs contain three 1220 × 320mm boards and are advertised as covering 1.17m² per pack. The Akor OSB T&G loft boards are 1220 × 300 × 18mm and supplied in packs of three. :contentReference[oaicite:5]{index=5}
Armstrong Loft Board Options
Armstrong's loft boards collection includes individual flooring boards as well as complete loft boarding kits. The kits combine flooring with loft legs, which can be useful where additional height is required to maintain insulation depth beneath the boarded area. :contentReference[oaicite:6]{index=6}
| Armstrong option | Board / kit information | Suitable calculation |
|---|---|---|
| Akor Chipboard Loft Boards | 1220 × 320mm · 3 boards per pack · 1.17m² stated coverage | Calculate packs from net loft area |
| Akor OSB T&G Loft Boards | 1220 × 300 × 18mm · 3 boards per pack | Calculate packs from board dimensions / coverage |
| Arranwood Chipboard Loft Boarding Kit | Flooring boards and loft legs | Calculate required boarded area then select suitable kit |
| Arranwood OSB Loft Flooring Kit | OSB flooring and loft legs | Calculate required boarded area then select suitable kit |
How to Calculate Loft Boarding
Start by measuring the length and width of the loft area you want to board. Multiply these measurements to find the total area in square metres.
If the loft is an irregular shape, divide it into simple rectangular sections. Calculate each section and add the results together.
Next, subtract any areas that will not be boarded. Finally, divide the net area by the coverage of the chosen loft board or pack and add your waste allowance.
Example: 4m × 3m Loft
A rectangular loft measuring 4m by 3m has a total area of:
4m × 3m = 12m²
If 1m² is left unboarded around an obstruction, the net boarded area is:
12m² − 1m² = 11m²
If you are using a loft board pack covering 1.17m², the basic requirement is approximately 9.4 packs. The calculator rounds this up to a complete pack and adds the selected waste allowance.
Loft boards are supplied in complete boards and packs. You cannot normally order part of a pack, so the calculator rounds the required quantity up to the next complete pack.
Should I Use Loft Legs When Boarding a Loft?
If you are adding loft flooring over insulation, the available depth above the insulation needs to be considered carefully. Raising the boarding system can provide space for insulation beneath the boards rather than compressing it.
Armstrong's loft board collection includes complete Arranwood flooring kits with loft legs as well as individual loft boards. :contentReference[oaicite:7]{index=7}
The correct height and arrangement depend on the existing joists, insulation depth and construction. Always follow the manufacturer's installation instructions and make sure the supporting structure is suitable.
Loft Boarding Over Insulation
Modern loft insulation can be significantly deeper than the height of older ceiling joists. Simply laying boards directly across the joists can compress insulation and reduce its effectiveness.
A raised loft boarding system can create a void above the insulation. Loft legs or another suitable support system can therefore be useful where the finished floor needs to sit above the insulation.
Armstrong specifically highlights the use of loft legs with raised boarding systems in its loft board information. :contentReference[oaicite:8]{index=8}
How Much Loft Boarding Do I Need?
The amount of loft boarding you need is based on the area you actually intend to floor rather than necessarily the entire footprint of the loft.
You may choose to board only part of the loft for storage, leaving areas around roof structures, tanks, services or other obstructions unboarded. This can reduce both the material requirement and the installation time.
Loft Board Calculator FAQs
How do I calculate how many loft boards I need?
Measure the length and width of the area you want to board, multiply them to calculate the square metre area, then divide the result by the coverage of the chosen loft board or pack. Add a waste allowance and round up to a complete board or pack.
How many loft boards do I need for a 10m² loft?
The exact number depends on the board size. For example, Armstrong's chipboard loft boards are supplied in packs of three and each pack is stated to cover 1.17m². A 10m² area would therefore require approximately 8.55 packs before allowing for waste, meaning at least 9 complete packs before any additional allowance. :contentReference[oaicite:9]{index=9}
How many loft boards are in a pack?
Armstrong's Akor chipboard loft boards are supplied in packs of three, as are the Akor OSB T&G loft boards listed in the current loft board collection. :contentReference[oaicite:10]{index=10}
How much area does a pack of loft boards cover?
The Armstrong Akor chipboard loft board pack contains three 1220 × 320mm boards and is stated to cover 1.17m². Coverage for other products should be checked against the individual product specification. :contentReference[oaicite:11]{index=11}
Can I board my loft over insulation?
Loft boarding can be installed above insulation where a suitable raised support system is used and the construction allows it. Raising the boards can help avoid compressing insulation. Always check the installation requirements and ensure the loft structure is suitable.
Do loft boards need to go across the joists?
Armstrong's product guidance states that the long sides of its chipboard loft boards should be laid at 90 degrees to the joists and that board ends should meet on a joist. Follow the installation instructions for the exact product being used. :contentReference[oaicite:12]{index=12}
Should I leave a gap between loft boards?
Follow the manufacturer's installation instructions for the specific board. Tongue and groove loft boards are designed to interlock, and the correct installation method can vary between products.
What are loft boards used for?
Loft boards create a stable platform for storage and access. Armstrong describes its loft boards as suitable for creating additional storage space and a more functional loft area. :contentReference[oaicite:13]{index=13}
Are loft boards structural?
Not necessarily. Armstrong's Akor chipboard loft board product is described as non-structural flooring board for creating a floor over existing flooring. The suitability of any board for a particular load or use must be assessed against the manufacturer's specification and the existing loft structure. :contentReference[oaicite:14]{index=14}
How much extra should I allow for loft board waste?
Around 10% is a useful starting point for many loft boarding projects, particularly where there are roof structures, hatches and other obstructions. A simple rectangular loft may require less, while a complicated layout can require more.
What is better for loft boarding, chipboard or OSB?
Both are engineered wood products that can be used for loft flooring where the particular product and installation are suitable. Armstrong describes its OSB loft panels as offering strength and durability, while its chipboard loft boards are designed as easy-to-handle tongue and groove flooring panels. The correct choice depends on the intended use and the manufacturer's specification. :contentReference[oaicite:15]{index=15}