60mm Loft Insulation

60mm loft insulation sits within a practical intermediate thickness range. It is not a thin detailing layer, and it’s not a full-depth cold loft upgrade either. It’s a practical working thickness that is commonly specified within controlled build-ups, especially where space, structure, or headroom limits what you can install.

This depth provides a balance between thermal improvement and construction constraints such as headroom and build-up limits. It is common in refurbishments, loft conversions, and staged upgrades where insulation is layered.

What is 60mm thick loft insulation?

Loft insulation 60mm thick refers to insulation boards or mineral wool manufactured to a fixed 60mm depth. That depth, together with the material’s thermal conductivity, determines the level of thermal resistance the material can deliver.

Performance depends on material type:

• PIR (λ ≈ 0.022 W/mK)
• Rock mineral wool (λ ≈ 0.035 to 0.040 W/mK)

Because PIR rigid insulation has lower thermal conductivity, 60mm PIR provides a higher thermal resistance per millimetre than mineral wool at the same depth, making it well suited for improving thermal performance where space is tight and high performance per millimetre matters.

The 60mm loft insulation thickness does not meet current recommended targets on its own in a cold loft floor. Current guidance typically recommends approximately 270mm of mineral wool at the loft floor level in existing homes. So, insulation loft 60mm is normally used as part of a layered system.

60mm thick loft insulation contributes meaningful thermal resistance within floors, roofs, and walls when specified properly, and it does this without creating excessive build-up.

What is 60mm loft insulation thickness used for?

Loft insulation 60mm thick works best on:

Floors (between joists)

In loft conversions, joist depth often dictates insulation depth. If you have 100mm joists and need space for services, installing 60mm PIR between suitably sized joists allows for:

• Excellent thermal performance
• Room for wiring/plumbing
• Space for additional insulation layers

Often, another insulated layer is added below or above to reduce timber cold bridging.

A thick 60mm Celotex loft insulation layer is practical here because it improves thermal insulation without raising finished floor levels too much.

Roofs (warm roof construction)

In warm roof build-ups, 60mm PIR insulation board may be installed:

• Above rafters, or
• Above rafters combined with insulation between rafters

On its own, it will not achieve the typical U-value in a compliant pitched roof buildup. But combined with deeper insulation between rafters, it forms part of a compliant structure.

In hybrid or internally insulated pitched roof systems, 60mm PIR insulation board may be installed below rafters as a continuous layer to reduce cold bridging.

Pitched Roof (cold loft floor level)

At the joist level in a traditional cold loft, a pitched 60mm wool loft insulation is usually the first layer between joists. Additional layers are then laid crosswise above to reach the compliant depth.

On its own, 60mm thickness loft insulation at the loft floor level is insufficient for current standards, but it is commonly used in staged upgrades.

Walls (stud and framing systems)

For timber or metal stud walls, 60mm PIR fits comfortably within 75mm–100mm studs, leaving room for service voids or additional insulation.

Mineral wool like Rockwool loft insulation 60mm improves both thermal and acoustic control. It is often selected where fire resistance and sound control are a priority.

Framing Walls

In timber framing, a 60mm rigid board can be used internally as a continuous insulated lining. This reduces cold bridging across studs and improves overall wall insulation performance.

It is common in retrofit upgrades where external insulation is not possible.

Internal Masonry Wall

For solid brick homes, 60mm PIR bonded to plasterboard provides a meaningful reduction in heat loss without drastically reducing room size.

This is especially useful in older UK housing stock with uninsulated masonry.

Types of 60mm Loft Insulation

We stock two main categories:

PIR Insulation (rigid boards)

2400mm x 1200mm x 60mm rigid polyisocyanurate boards offer:

• Low thermal conductivity of 0.022 W/mK)
• High compressive strength
• Good moisture resistance
• Lightweight and easy to cut

Best suited for floors, roofs, framing walls, and internal linings where performance per millimetre is critical.

Mineral wool insulation (rolls or slabs)

Manufactured from volcanic rock fibres, mineral wool insulation products provide:

• Non-combustible classification (where stated euroclass A1)
• Strong acoustic performance
• Vapour permeability
• Flexible friction fit

Rockwool loft insulation 60mm is well suited between joists or studs where fire resistance and sound control are important.

Benefits of upgrading to 60mm loft insulation in UK homes

Upgrading to 60mm insulation improves thermal resistance compared to shallow legacy insulation. In loft conversions, it helps stabilise room temperatures and reduces reliance on heating systems.

While deeper insulation is required for full compliance at the loft floor level, upgrading in stages using thick 60mm PIR insulation for the loft is often the most realistic route in retrofit properties.

We supply 60mm loft insulation at competitive pricing with fast nationwide delivery. Speak to our team for trade discounts, a fast quote, and reliable delivery to your site.