Where to buy 100mm loft insulation online?

You can buy 100mm thick loft insulation online from Insulation Wholesale. We offer PIR boards, glass wool rolls, and rock mineral wool slabs in loft Insulation 100mm options, ready for dispatch. With bulk discounts, fast nationwide delivery, and knowledgeable support, we make it straightforward to order the right material for your job.

How good is 100mm loft insulation?

It is effective when used correctly. The answer depends not only on thickness, but also on material and build-up. 100mm mineral wool provides roughly 2.27 m²K/W at 0.044 W/mK. On its own, this is typically insufficient to meet modern upgrade targets for the loft insulation roll. But as part of a layered build-up, it performs well. 100mm PIR at 0.022 W/mK achieves around 4.5 m²K/W, giving significantly stronger thermal resistance per layer.

How to cut loft 100mm insulation?

Mineral wool insulation roll: Use a long insulation knife or serrated blade, and cut against a straight edge to get clean lines. PIR boards: Score with a sharp knife, and then snap over a straight edge. A fine-tooth saw gives better control when making multiple cuts.

DIY guide for installing 100mm loft insulation

Check joist depth and condition. Lay mineral wool between joists without compressing it. If using PIR, cut precisely to friction-fit between timber members. Keep ventilation paths clear at eaves in cold roofs. Install cross-layer insulation if required to meet U-value targets. Do not cover recessed light fittings unless rated for insulation contact. Follow Approved Document L and manufacturer instructions for the specific application.

What is the R-value of 100mm mineral wool loft insulation?

R-value is based on the product’s thermal conductivity. It is calculated as thickness (in metres) divided by thermal conductivity (λ) Here’s how R-values stack based on different lambda values: 0.044 W/mK delivers R ≈ 2.27 m²K/W 0.037 W/mK delivers R ≈ 2.70 m²K/W 0.034 W/mK delivers R ≈ 2.94 m²K/W We supply 100mm loft insulation at competitive prices and offer fast nationwide delivery direct to your site or project location. Ready to insulate your home? Contact us today.

100mm Loft Insulation At Wholesale Prices

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Products in 100mm Loft Insulation

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100mm Celotex GA4100 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2

100mm Celotex GA4100 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.

£41.28£49.54 Ex VATInc VAT
£14.33£17.20 Per M2 Add to cart
100mm Ecotherm Eco-Versal Rigid PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2

100mm 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.

£41.45£49.74 Ex VATInc VAT
£14.39£17.27 Per M2 Add to cart
100mm Isover Spacesaver Insulation Loft Roll 14.13m2

100mm Isover Spacesaver Insulation Loft Roll is an efficient and easy-to-install solution for insulating loft spaces, designed to enhance energy efficiency and home comfort.

£32.79£39.35 Ex VATInc VAT
£2.32£2.78 Per m2 Add to cart
100mm Knauf Insulation Loft Roll 44 Combi-Cut 13.89m2 Roll

Knauf Insulation Loft Roll 44 is a non-combustible glass mineral wool roll supplied in a Combi-Cut format. It is designed for use in cold lofts. Manufactured using Knauf Insulation’s unique bio-based binder, ECOSE® Technology.

£28.62£34.34 Ex VATInc VAT
£2.06£2.47 Per m2 Add to cart
100mm ODE Insulation Loft Roll 10.83m2

100mm ODE Insulation Loft Roll is a highly effective thermal loft solution for improving home energy efficiency. Made from eco-friendly materials, it offers a simple and effective way to improve comfort while lowering energy costs.

£21.66£25.99 Ex VATInc VAT
£2.00£2.40 Per m2 Add to cart
100mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2

100mm 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.

£39.98£47.98 Ex VATInc VAT
£13.88£16.66 Per M2 Add to cart
100mm Rockwool Flexi Slab Acoustic Insulation 1200mm x 600mm 4.32m2 Pack

100mm 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.

£42.91£51.49 Ex VATInc VAT
£9.93£11.92 Per m2 Add to cart
100mm Rockwool RWA45 Acoustic Insulation Slab 1200 x 600mm 2.88m2 Pack

100mm Rockwool RWA45 has been developed for thermal, acoustic and fire performance in a range of construction types. It is suitable for applications on partition walls, ceilings, floors and roofs.

£23.41£28.09 Ex VATInc VAT
£8.13£9.76 Per m2 Add to cart
100mm Superglass 44 Multi Loft Roll Insulation 12.12m2 Roll

Multi-Roll 44 is a lightweight, non-combustible glass mineral wool roll, designed to provide thermal insulation in lofts. This roll is typically used for insulating loft spaces and cold roofs but can also be used in a multitude of different applications.

£27.35£32.82 Ex VATInc VAT
£2.26£2.71 Per m2 Add to cart
100mm Ecotherm Eco-Bond PIR Insulation Board 1200mm x 1200mm (4′ x 4′) Pack of 4 (5.76m2)

100mm Eco-Bond PIR insulation boards provide a lightweight, easy-to-install solution for new roofs or upgrading existing ones. Ideal for use with fully adhered single-ply waterproofing on concrete, metal, and timber decks.

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100mm IKO Enertherm ALU PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2

100mm 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.

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100mm Kingspan Therma TP10 / TF70 / TW55 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 3 (8.64m2)
All three models 100mm Kingspan Therma PIR Insulation Board:
- 100mm Thermapitch TP10
- 100mm Thermafloor TF70
- 100mm 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.
£167.59£201.11 Ex VATInc VAT
£19.40£23.28 Per M2 Add to cart
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100mm Mannok PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2

100mm Mannok PIR Insulation Board is an excellent choice for anyone looking for a high-performance insulation solution that provides superior thermal efficiency. It is ideal for use in any construction project, such as commercial and residential, in wall applications as well as roofing and flooring applications.

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100mm Unilin Thin-R PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pallet of 24 (69.12m2)

100mm 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.

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