180mm Insulation

180mm insulation refers to insulation material that is 180mm thick from the warm side to the cold side. It is usually made from materials that use trapped air or closed-cell structures to restrict heat transfer.

What is 180mm thick insulation?

180mm insulation thickness is manufactured to a consistent depth of 180mm. This is a practical size that aligns with some common timber and steel joist depths used in floor, roof, and wall build-ups.

The material provides an effective thermal barrier (resisting heat flow) and offers useful acoustic dampening (reducing sound transmission).

Glass mineral wool versions have intertwined fibres that trap still air, giving good insulation and sound absorption.

Rock mineral wool is a bit denser and excellent at heat resistance and fire safety.

Both kinds at 180mm thickness are installed between structural membranes to fill the gap snugly.

What is insulation 180mm thick used for?

Insulation 180mm thick layers are most commonly used in:

Roofs

• Fits between rafters or joists in pitched and flat roof structures.
• Reduces heat loss in lofts during winter and slows heat gain in summer.

Floors

• Fills the space between floor joists, reducing heat transfer to the unheated areas below.
• Improves comfort underfoot and helps meet Building Reg requirements.

Walls

• Used in framed wall systems (timber or steel) to improve thermal and acoustic performance.
• Can be part of external wall builds where deeper insulation is needed.

Partitions

Works in internal walls or party walls for sound control and heat retention.

180mm thick insulation is particularly suitable when you need better performance – like when upgrading an existing building or meeting more stringent U-value targets.

Benefits of 180mm insulation thickness

Choosing 180mm insulation ensures:

Thermal control

180mm insulation significantly reduces heat loss compared to thinner layers. With a deeper layer to pass through, heat moves slowly. This saves energy and keeps temperatures more stable.

Sound reduction

Both glass and rock mineral wool at this depth help absorb sound, making rooms quieter by cutting down noise transfer through floors and walls.

Fire safety

Many mineral wool types are noncombustible (Euroclass A1), meaning they will not significantly contribute to fire spread – an important safety feature in building envelopes.

Moisture and breathability

These fibres allow vapour to pass through without trapping water when correctly detailed with vapour control layers. That reduces the risk of rot and condensation in many constructions.

Material differences

Glass mineral wool insulation:

• Lighter weight, easy to cut and handle.
• Great for thermal and acoustic purposes in roofs and floors.
• Often carries excellent fire resistance, too.

Rock mineral wool (e.g., Rockwool flexi slab):

• Firmer and more resilient in gaps.
• Excellent acoustic control and fire resistance.
• The Flexi edge product helps you fit it between studs without gaps, improving performance.