110mm Insulation Board

The 110mm insulation board is a rigid thermal insulation panel used to significantly reduce heat loss in building envelopes. It is specified where sufficient construction depth is available to accommodate a high level of insulation.

A 110mm rigid board is often installed to meet tight U-values for walls, roofs, and floors. It is suitable for refurb projects, extensions, and high-spec new builds with tight thermal performance goals.

What is 110mm thick insulation board?

A 110mm thick insulation board is a factory-manufactured rigid panel with a fixed depth of insulation running across the full board. Unlike mineral wool, it does not compress or lose dimensional stability over time. When fitted correctly, its thermal performance remains stable over its service life.

Most 110mm rigid panels are made from closed-cell foam, where gas trapped within millions of tiny sealed cells slows heat transfer.

Most boards are supplied with square or profiled edges, designed to be cut accurately and installed tightly so heat cannot leak through gaps. At this thickness, correct jointing, fixing methods, and vapour control detailing become increasingly integral to overall performance.

What is 110mm insulation thickness board used for?

A 110mm insulation thickness board is used where thinner boards would not meet spec, including applications like:

• Framing walls – Timber or steel stud walls that need strong thermal insulation without relying on deep cavities.
• Internal masonry walls –  Often installed on timber battens to accommodate the board and internal lining.
• Floors – Solid or suspended floors where downward heat loss is a problem.
• Pitched roofs – Between, below, or over rafters to achieve low design U-values.
• Flat roofs – Warm roof systems where thickness is planned into the build-up.
• Cladding systems – Behind rainscreen or external finishes.

At this thickness, insulation makes a significant contribution to reducing energy demand and improving internal comfort year-round.

Types of 110mm insulation board

Insulation Wholesale stocks two main rigid boards at 110mm depth:

PIR Insulation (Polyisocyanurate)

PIR is the most common choice. It offers strong thermal performance for its thickness and is easy to handle. Foil facings can assist with airtightness when joints are taped and detailed correctly.

Phenolic Insulation Foam Board

Phenolic boards insulate slightly better than PIR at the same thickness. That means marginally lower U-values. They are more brittle, however, and usually cost more.

PIR and phenolic foam are both rigid and built for long-term use.