70mm insulation sits between thin lining insulation and deeper structural insulation layers. It is ideal when a project requires a significant thermal improvement but cannot accommodate the space required for thicker insulation.
It is a suitable choice for refurbishment work, lining upgrades, and tight timber details.
What is 70mm thick insulation?
70mm thick insulation, sometimes referred to as insulation thick 70mm, measures exactly 70 millimetres when installed at its nominal thickness.
This depth of insulating material reduces heat transfer by trapping still air (soft products) or by resisting heat flow through rigid foam boards.
While it is 10mm slimmer than 80mm thick insulation, the mechanism at work is the same: less heat escapes, resulting in improved thermal retention within the building.
What is 70mm insulation thickness used for?
70mm insulation boards and slabs are typically used when the build-up will not allow that extra depth. Common uses include:
Internal wall upgrades where space is tight
Timber stud partitions
Warm roof constructions where rafter depth or build-up height is restricted (usually part of a multi-layer build-up)
Floors above unheated spaces, such as garages or voids
Types of 70mm insulation
Installers consider placement, fit, moisture risk, and required installation skills when choosing one type of 70mm insulation over another. The types of products available in 70mm insulation thickness include:
70mm soft insulation materials (mineral wool, glass wool): These rely on air pockets and are more tolerant of minor dimensional variation. Therefore, you do not need to cut them to the exact size that fits the space; they can be cut slightly wider or oversized and still fit snugly due to their compressible nature.
70mm hard insulation boards (PIR, phenolic, EPS, XPS): These resist heat flow more strongly per millimetre but demand precise cutting.
It is made from spun rock fibres pressed into slabs. It has a dense yet springy structure and holds its shape once fitted.
Works by trapping still air between fibres. Typical thermal conductivity ranges from 0.035 to 0.040 W/m.K. It is noncombustible and vapour-permeable, allowing moisture to pass through the structure.
Best for stud walls, partitions, and floors between joists. Also used where fire resistance and sound control matter as much as heat retention.
Formed from molten recycled glass spun into a lightweight, fibrous mat. It relies on air pockets to restrict heat flow and has a thermal conductivity of 0.032–0.040 W/m.K.
A compressible material that is common in timber frames, loft slopes, and wall linings, where insulation should friction-fit into place.
This is a closed-cell foam similar to PIR but with a finer internal structure.
It offers slightly better thermal performance than PIR, typically 0.020–0.023 W/m.K. It is more brittle than PIR and therefore requires careful handling during installation.
Ideal when maximum insulation is needed in the smallest possible depth, especially in projects with strict build-up limits.
These are light panels made from expanded polystyrene beads fused together. They are vapour-permeable and dimensionally stable compared to closed-cell foams.
Their thermal conductivity typically ranges from 0.030 to 0.038 W/m.K, depending on grade.
Common in floors and cavity wall systems. Also, for areas that need a balance of insulation and breathability.
XPS is a denser form of polystyrene with a smooth, closed-cell surface. It maintains performance even in damp conditions.
Has lower water absorption than EPS with typical thermal conductivity values of approximately 0.029–0.034 W/m.K. Ideal for floors, inverted roofs, and ground-contact areas where moisture resistance is critical.
Benefits of insulation 70mm thickness
70mm delivers gains such as:
Noticeable heat-loss reduction
Easier detailing around windows and services
Less disruption in refurb projects
Compatible with many existing frames
Improves occupant comfort in addition to lowering U-values
At Insulation Wholesale, you can purchase 70mm Insulation at low wholesale prices with fast delivery for most of items within 2-5 days. Competitive rates guaranteed.
FAQ
Where to buy 70mm insulation?
You can buy insulation 70mm online from Insulation Wholesale. We stock both soft and rigid options, supply well-known UK brands, and keep pricing competitive across thicknesses. Our team helps you match the insulation to the build detail, not just the spec sheet, so the correct product is specified and installed the first time.
How to cut 70mm insulation?
Soft insulation: Use a long knife or saw and cut slightly oversize.
Rigid boards: Score deeply along a straight edge, then snap or saw for clean edges.
Always aim for snug contact, as gaps allow heat to pass through the material more freely.
How much is 70mm insulation?
Prices vary by material. Products offering higher thermal performance per millimetre typically cost more.
Soft insulation rolls or slabs typically cost £4–£8 per m².
Rigid foam boards are typically £10–£20 per m², depending on type and brand.
Please note that these price ranges are indicative and significantly vary by brand, specification, and order volume.
70mm Celotex GA4070 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£33.53£40.24Ex VATInc VAT£11.64£13.97Per M2Add to cart
70mm Ecotherm Eco-Versal is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Ecotherm Eco-Versal is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£33.59£40.31Ex VATInc VAT£11.66£13.99Per M2Add to cart
70mm Recticel Eurothane GP is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Recticel is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£32.44£38.93Ex VATInc VAT£11.26£13.51Per M2Add to cart
70mm IKO Enertherm ALU PIR (polyisocyanurate) insulation is a top-quality insulation board featuring a rigid PIR foam core and reflective aluminium foil facings. It delivers outstanding thermal performance and moisture resistance, making it suitable for various installations and an ideal choice for different energy-efficient projects.
All three models 70mm Kingspan Therma PIR Insulation Board:
70mm Thermapitch TP10
70mm Thermafloor TF70
70mm Thermawall TW55
share the same high-performance PIR core and low-emissivity foil facings, offering excellent thermal efficiency and easy installation. Although labeled differently, these boards share identical technical specifications.
£172.51£207.01Ex VATInc VAT£14.97£17.96Per M2Add to cart
70mm Rockwool Flexi has been designed as a multi-use, dual-purpose acoustic and thermal mineral wool insulation with a unique flexible edge along one side. It is suitable for use all over the home, in pitched roof rafters, framed external walls, internal partitions, intermediate floors, separating walls and floors, and timber suspended ground floors.
70mm Unilin Thin-R PIR insulation is a foil faced, high-performance insulation solution that offers exceptional thermal efficiency and durability. This polyisocyanurate insulation board, formerly known as Xtratherm, is ideal for a range of applications, such as floors, pitched roofs, and walls.
