Which PIR board size reduces cutting on site?

Check the joint pattern and laying direction required by the system. For boards bonded to plasterboard, account for joints in the finishing layer too. Narrow offcuts cannot necessarily be used anywhere. Minimum piece dimensions and fixing rules must match the intended system.

Boards around 600 × 1200 mm are easier to handle in confined rooms and can suit lofts or walls with many openings. Every extra joint still needs fitting and finishing to system requirements. Compare the reduction in waste with the work at the extra joints.

A 3.5 × 2.7 m wall covers 9.45 m². Dividing by a nominal 0.72 m² per board gives a minimum of 14 boards. This is only an arithmetic lower bound. Joint layout, actual coverage and which offcuts can be reused may increase the order.

A 1200 × 2400 mm board has a nominal area of 2.88 m². The same wall needs at least four by area, but a vertical board leaves a strip above it in a 2.7 m high room. Draw the strip and its joint. A larger board still needs cutting where its dimensions do not match the room.

Composite boards may come in other lengths such as 2600 mm. Check the range offered for the specific product. For manual handling, consider weight and stiffness. A long thin panel can need a different handling method from a small board of equal thickness.

Profiled edges affect coverage. Check whether dimensions describe the whole board or the area covered once joined, especially with laps or tongue-and-groove edges. Calculate with the correct figure for the product. A small discrepancy repeated over many rows may change the number of packs.

Mark factory and cut edges on the drawing. Facings and edge direction may prevent an offcut being turned around. Material cut from an opening may not fit beside it. Determine the allowance from the plan, since a plain wall and a roof with many changes of direction produce different waste.

Check door widths, corridor heights and turns on stairs. A board may fit through a doorway but cannot necessarily turn on the landing. Try a lightweight template or check the route on plan. Cutting every board before carrying it inside can cancel the benefit of the larger size.

Agree pack sizes, unloading and dry storage when ordering. Protect boards from weather and edge damage. Transport wrapping may not be adequate protection on site. Separate packs by work stage to reduce repeat handling and damage to facings.

Specify format, thickness, facing, edge and whole packs. Include the allowance from the actual layout and a place to store reusable offcuts. Check consumption after the first area is complete, before distributing all the packs.

On delivery, inspect corners and facings and check dimensions. A damaged edge may prevent a tight joint even if the face looks intact. Check the variant markings too: the correct size with the wrong facing may be unsuitable for the planned finish.