How to install PERINSUL HL at the base of internal partition walls

Ben Tan - Technical advisor

PERINSUL HL can provide a continuous thermal break at the base of load-bearing and non-load-bearing partitions alike. Positioned at the appropriate level, PERINSUL HL helps to maintain continuity of the ground floor insulation layer anywhere it is interrupted by the construction of a partition.

Laying PERINSUL HL blocks

at the base of an internal wall

An internal partition may be constructed off its own foundation and supporting wall, or the concrete floor slab directly. In either case, the structure should be specified and constructed in accordance with relevant standards and accepted good practice.

Apply a 10mm mortar bed to the masonry wall or floor slab, and lay the PERINSUL HL blocks so they are level and fully supported. They should be laid end-to-end, closely butted, and with no vertical mortar (no perpend joints) to maintain their continuity and load-bearing capacity.

If the damp proof membrane or damp proof course has to lap over the partition, it can be above or below the PERINSUL HL blocks. When the ground floor insulation is laid, it should butt tightly to the partition wall, in order to avoid air gaps.

Constructing the internal wall


The blockwork of a masonry partition can simply be continued from the level of the PERINSUL HL blocks, sitting the first masonry course on a 10mm mortar bed as normal. PERINSUL HL blocks are designed around standard masonry unit sizes, so should course in with adjoining walls. For a 100mm wide PERINSUL HL block, construct the partition in 100mm blocks.

If the first row of masonry features hollow or indented bricks or blocks, any voids should be filled with mortar to ensure an even spread of load to the PERINSUL HL layer below.

For timber stud partition sole plates, or steel partition channel tracks, the usual method of attachment to the support structure is mechanical fixing. However, it is not recommended to fix through PERINSUL HL blocks, as this has a detrimental impact on their function as a thermal break.

In either scenario, creating a perpend joint between the PERINSUL HL blocks can provide a location for fixings to secure the base of the partition frame. Contact FOAMGLAS® for advice about the appropriate fixing method based on your specific project.