They are placed around the edges of a room before laying a new floor to prevent heat loss where the floor meets the wall. They also provide a small expansion gap, which stops the floor from cracking as it naturally expands and contracts over time.
Rigid PIR Perimeter Insulation
Perimeter strips provide a thermal break at the junction where a floor meets an external or internal wall. This category features rigid polyisocyanurate (PIR) strips, available in standard thicknesses such as 25mm and 50mm, along with varying widths to suit different floor depths. They are inserted vertically around the edges of a room before the final floor finish is applied, helping to prevent cold spots and reduce thermal bridging. By ensuring continuity between the wall and the Floor Insulation, these products help meet thermal performance standards and reduce overall heat loss.
These insulation strips are typically used in solid floor constructions, especially when laying a new concrete slab or Screed. They are placed against the perimeter walls to accommodate the natural expansion and contraction of the floor, which is particularly important in rooms fitted with underfloor heating. Before the pouring process begins, the strips are positioned tightly against the wall and often taped or sealed to a Damp Proof Membrane to prevent any liquid from escaping and to maintain a watertight barrier.
The rigid PIR material features a low emissivity foil facing, which provides thermal resistance while remaining lightweight and easy to cut. Their pre-cut dimensions save time on site by offering a consistent depth that ensures compliance with building regulations regarding floor detailing. Because they are straightforward to position and secure, they simplify the installation process and provide stability without compressing under the pressure of floor finishes. Once the floor is set, the upper edges can be trimmed flush to allow for a clean transition when fitting wall linings like Plasterboard.
Perimeter Strips FAQ's
You stand the strips vertically against the base of all walls in the room. They should be pushed tightly into the corners and secured in place so they do not move during the pouring of the floor finish. Once the floor has dried completely, any excess material sticking up above the floor level can be trimmed off with a utility knife.
Yes, they are highly recommended when installing underfloor heating. The heating and cooling cycles cause the floor to expand and shrink more than a standard unheated floor. The strips act as a cushion to absorb this movement and protect the floor from structural damage.
Rigid polyisocyanurate strips are very easy to cut to the required length. You can use a standard fine-toothed hand saw or a sharp utility knife to score and snap the material, ensuring a snug fit in corners or around awkward obstacles.
The required thickness depends on your specific floor build-up and insulation requirements, but 25mm is a very common starting point for solid floors. Thicker options, such as 50mm, are available if your project demands higher thermal resistance at the wall junctions.