If a wall schedule says only “100 mm PIR”, neither the product to be supplied nor the evidence required from the contractor is clear. Separate the requirements first: some relate to a material, others to the complete wall and its joints. Against each figure, note what it describes and where it comes from. This lets you compare a proposal with the design without attributing a tested wall assembly's performance to a board alone. Here is how to review the information before accepting a substitution.

Floor insulation is often chosen before the owner knows where a heavy stove, aquarium or cabinet on narrow feet will stand. Mark these positions on the floor plan as early as possible. Two objects of equal mass can load a floor differently: one rests on a continuous plinth, the other on four small feet. Durability depends on the full build-up, including the substrate, insulation, screed and finish. Here is what to tell the designer about the fittings, and why a figure on a PIR board data sheet is not a ready-made furniture weight limit.

Insulating a house in stages requires coordination between today's work and future work. A roof using PIR boards, a later façade upgrade and replacement windows should not develop as three unrelated solutions. Otherwise, later work may lack space to connect the layers or require finished areas to be reopened. This guide explains how to list those interfaces and connect them to the programme. It distinguishes the final detail, interim condition and handover between contractors. It does not specify one universal sealing or fixing method; details must follow the design and compatible material systems. A planned sequence supports insulation continuity, airtightness and future access for maintenance.

An internal ceiling can separate a heated or climate-controlled room from the roof void. In a cattle shed or warehouse, its appearance is only one consideration. Choose insulation, facings, supports and wall junctions to suit the space. PIR boards help keep the build-up thin. For a durable ceiling, plan how to control moisture, clean the lining and reach services above it. This is an internal ceiling, distinct from decorative soffit cladding beneath the eaves outside. In a farm building, the ceiling can form the room’s thermal boundary. The design must define the height and use of the void above: moving that boundary changes the room volume, ventilation and service routes.

A loft fit-out starts well before the first plasterboard goes up. Inspect the roof, plan the insulation and establish how the layers will be made airtight. Framing, lining and jointing follow. PIR boards can reduce the insulation thickness needed, but form only part of the lining system. The materials must work together around windows, walls and services. Check the roof covering, flashings, window junctions and timbers before concealing them. Repair leaks and timber damage first. When converting a loft, establish the load capacity of the floor and the applicable approval requirements. Partitions, flooring and furnishings add loads. Adequate headroom alone does not make a loft suitable for habitation.