Rafter Insulation

This insulation is fitted between the rafters of the roof. Rafter-level insulation combined with ceiling insulation can be used together where an existing attic space is converted.
59 products
Rockwool Flexi-Slab - All Sizes
Rockwool Flexi-Slab - All Sizes
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Vendor
Rockwool
Rockwool Flexi-Slab - All Sizes
  • Versatile dual-purpose insulation: thermal & acoustic
  • Patented flexible edge for easy installation
  • Euroclass A1 non-combustible, BS EN 13162 compliant
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£38.08£45.70
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Celotex 30mm TB4030 2.4m x 1.2m
Celotex 30mm TB4030 2.4m x 1.2m
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on orders over £300
Vendor
Celotex
Celotex 30mm TB4030 2.4m x 1.2m
  • Cost-effective Celotex TB4030 PIR insulation board
  • Lightweight, easy installation, high tensile strength
  • Fire and water-resistant, eco-friendly, long-lasting insulation for walls, roofs, and floors
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£13.30£15.96
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Celotex PL4025 37.5mm 2.4m x 1.2m
Celotex PL4025 37.5mm 2.4m x 1.2m
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Celotex
Celotex PL4025 37.5mm 2.4m x 1.2m
Shop a cheaper alternative product - Warmline PIR Insulated Plasterboard 1.2m x 2.4m
  • PIR insulation with zero ODP and low GWP.
  • Reduces installation time with combined insulation and plasterboard.
  • Suitable for various applications including roofs and walls.
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£32.75£39.30
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80mm Celotex GA4080 2.4m x 1.2m
80mm Celotex GA4080 2.4m x 1.2m
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Celotex
80mm Celotex GA4080 2.4m x 1.2m
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£27.45£32.94
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Mannok Insulation Board 1.2m x 2.4m (All Sizes)
Mannok Insulation Board 1.2m x 2.4m (All Sizes)
Vendor
Mannok
Mannok Insulation Board 1.2m x 2.4m (All Sizes)
  • Lightweight PIR insulation board
  • High thermal performance & strength
  • Eco-friendly, water-resistant, easy to cut
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£11.17£13.40
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Celotex PL4050 62.5mm 2.4m x 1.2m
Celotex PL4050 62.5mm 2.4m x 1.2m
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on orders over £300
Vendor
Celotex
Celotex PL4050 62.5mm 2.4m x 1.2m
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£43.60£52.32
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100% Sheepwool Insulation Optimal Roll (All Sizes)
100% Sheepwool Insulation Optimal Roll (All Sizes)
Vendor
Sheepwool
100% Sheepwool Insulation Optimal Roll (All Sizes)
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£99.89£119.87
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Kingspan Thermapitch TP10 Pitched Roof Board (All Sizes) 2.4m x 1.2m
Kingspan Thermapitch TP10 Pitched Roof Board (All Sizes) 2.4m x 1.2m
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on orders over £300
Vendor
Kingspan
Kingspan Thermapitch TP10 Pitched Roof Board (All Sizes) 2.4m x 1.2m
  • Effortless insulation with Kingspan Thermapitch TP10.
  • High density increases habitable space by up to 15%.
  • Trusted foil-facing technology prevents moisture buildup.
Regular price
£106.95£128.34
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Celotex PL4040 52.5mm 2.4m x 1.2m
Celotex PL4040 52.5mm 2.4m x 1.2m
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on orders over £300
Vendor
Celotex
Celotex PL4040 52.5mm 2.4m x 1.2m
Shop a cheaper alternative product - Warmline PIR Insulated Plasterboard 1.2m x 2.4m
  • PIR insulation with zero ODP, low GWP
  • Combines insulation and plasterboard
  • Speeds up installations, suitable for various applications
Regular price
£38.75£46.50
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Isover Spacesaver Ready-Cut - All Sizes
Isover Spacesaver Ready-Cut - All Sizes
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Vendor
Isover
Isover Spacesaver Ready-Cut - All Sizes
Shop a cheaper alternative product - Volcalis Easy Light Loft Roll 44
  • Flexible sizing & widths: 100mm to 200mm thickness; half, third, or full width options.
  • Eco-friendly: Up to 82% recycled glass with Zero ODP & GWP.
  • Easy, safe installation: Resilient, tear-resistant, non-combustible for a cozy, green home.
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£34.59£41.51
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Celotex PL4060 72.5mm 2.4m x 1.2m
Celotex PL4060 72.5mm 2.4m x 1.2m
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Vendor
Celotex
Celotex PL4060 72.5mm 2.4m x 1.2m
Shop a cheaper alternative product - Warmline PIR Insulated Plasterboard 1.2m x 2.4m
  • Rigid PIR construction with zero ozone depletion
  • Combines insulation and plasterboard for swift installation
  • Meets regulations, offers long-term energy savings
Regular price
£48.65£58.38
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12mm Celotex TB4012 2.4m x 1.2m
12mm Celotex TB4012 2.4m x 1.2m
Free Delivery
on orders over £300
Vendor
Celotex
12mm Celotex TB4012 2.4m x 1.2m
  • High-Performance Insulation: PIR composition, 0.022W/mK thermal conductivity.
  • Environmentally Friendly: Zero ODP, low global warming impact.
  • Versatile & Certified: Eliminates cold spots, meets Building Regulations, and offers energy savings.
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140mm Celotex XR4140 Insulation Board 2.4m x 1.2m
140mm Celotex XR4140 Insulation Board 2.4m x 1.2m
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on orders over £300
Vendor
Celotex
140mm Celotex XR4140 Insulation Board 2.4m x 1.2m
  • Cut-to-fit for rafters/joists
  • High thermal performance
  • Environmentally friendly
Regular price
£44.95£53.94
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EcoTherm Eco-Versal Insulation Board 2.4m x 1.2m - All Thicknesses
EcoTherm Eco-Versal Insulation Board 2.4m x 1.2m - All Thicknesses
Free Delivery
on orders over £300
Vendor
Ecotherm
EcoTherm Eco-Versal Insulation Board 2.4m x 1.2m - All Thicknesses
  • All-in-one Eco-versal Insulation Board for thermal conductivity (0.022 W/mK)
  • Rigid PIR core with aluminum composite foil facing, perfect for roofs, walls, and floors
  • Lightweight, easy to cut, and install compared to some other commonly used insulants; offers warmth and durability
Regular price
£11.17£13.40
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Celotex 20mm TB4020 2.4m x 1.2m
Celotex 20mm TB4020 2.4m x 1.2m
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Vendor
Celotex
Celotex 20mm TB4020 2.4m x 1.2m
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£12.72£15.26
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Rockwool RW3 Acoustic, Thermal, and Fire Performance Insulation Slabs (All Sizes)
Rockwool RW3 Acoustic, Thermal, and Fire Performance Insulation Slabs (All Sizes)
Free Delivery
on orders over £300
Vendor
Rockwool
Rockwool RW3 Acoustic, Thermal, and Fire Performance Insulation Slabs (All Sizes)
  • Superior thermal, acoustic, and fire insulation from volcanic rock
  • Versatile boards fit snugly into structures, reducing noise and absorbing sound
  • Durable, sustainable, and eco-friendly with various sizes and densities available
Regular price
£414.50£497.40
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£414.50 £497.40
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100% Sheepwool Insulation Premium Roll (All Sizes)
100% Sheepwool Insulation Premium Roll (All Sizes)
Vendor
Sheepwool
100% Sheepwool Insulation Premium Roll (All Sizes)
  • 100% Sheep Wool Insulation Premium Roll
  • Thermal conductivity: 0.0359 W/mK
  • Retains loft, eco-friendly, effective in moisture, and heat control
Regular price
£124.93£149.92
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Warmline XPS Insulated Plasterboard 1.2m x 2.4m - All Sizes
Warmline XPS Insulated Plasterboard 1.2m x 2.4m - All Sizes
Free Delivery
on orders over £300
Vendor
Warmline
Warmline XPS Insulated Plasterboard 1.2m x 2.4m - All Sizes
  • Top-notch insulation: Extruded polystyrene foam on robust plasterboard.
  • Effortlessly meets Part L regulations for enhanced warmth.
  • Easy installation, generous dimensions, and exceptional thermal efficiency.
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130mm Celotex XR4130 2.4m x 1.2m
130mm Celotex XR4130 2.4m x 1.2m
Free Delivery
on orders over £300
Vendor
Celotex
130mm Celotex XR4130 2.4m x 1.2m
  • Premium 130mm Celotex XR4130 insulation
  • Polyisocyanurate (PIR) for eco-friendly high performance
  • Cost-effective, BBA certified, A+ rating, meets Building Regulations
Regular price
£43.95£52.74
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Warmline PIR Insulated Plasterboard 1.2m x 2.4m - All Sizes
Warmline PIR Insulated Plasterboard 1.2m x 2.4m - All Sizes
Free Delivery
on orders over £300
Vendor
Warmline
Warmline PIR Insulated Plasterboard 1.2m x 2.4m - All Sizes
  • ✅ Achieves The Same U-Value As Celotex PL4000
  • ✅ Thermal Conductivity Of 0.022
  • ✅ Built-In Vapour Barrier
Regular price
£32.52£39.02
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Rafter Insulation: Features, Uses And Functions
Insulation is a great way to preserve heat in an attic or a roof space. There are many ways to install insulation, and once completed, comfort and protection within the home or office environment is guaranteed. Attic insulation are not only responsible for slowing down the movement of air, but they are also useful for sound absorption. There are simply many ways to install roof insulation, and one can do it economically as well. These insulation products help regulate the temperature and slow down the movement of air between on space to another, thus regulating the temperature of the air by the time it passes through the insulation.

Why should you insulate?

• You should insulate because you can improve your energy efficiency and reduce your heating bills.

• The environment in which you live or work will become more comfortable.

• Supports the environment by reducing greenhouse emissions.

• Can protect against unwanted noises and fire.

• It is cost effective and easy to install in most cases.

If you are building a new house or just renovating, you have to make sure that you install the correct insulation for the attic or roof. This which will help prevent the concentration and buildup of condensation with the aid of the correct ventilation. Your home can lose up-to 20-30% of heat through the roof when the insulation is not installed properly.

The most common insulation material used in this process is glass mineral fiber and semi-rigid Insulation Board. The kind of material you use will depend on the joists and rafters, the size of your attic/roof and its end use. Along with mineral wool, glasswool and rigid board insulation there are also multi-foil options available also. Multi-foil insulation is typically used along with the aforementioned insulation products, above and below the rafters. If fit correctly multi-foil insulation can create an airtight seal or close to an airtight seal to assist even greater with controlling the movement of air into and out of a building.

Installing these types of insulation between rafters is a very important process, and one must make certain that there are no gaps in between the insulation and the rafters or joists whatsoever. Any sort of gaps between the rafters or joists could result in the insulation being ineffective as gaps will cause air to rush through them. This rush of air is typically cold air from outside. When installed without gaps the insulation will control the flow and regulation of air.. Rigid foam insulation needs to be placed tightly during installation in the attic rafters so that no or very little air can leak out from within the attic space. The better the fit the more control you get over regulating air flow.

High-quality products and materials coupled with good installation will assist in providing your home or office space with a better Uvalue. U valve is a unit of measure used to measure the effectiveness of insulation within a building. Properly installed insulation with a low thermal conductivity will provide a low Uvalue.

Using Fiberglass
Using fiberglass is a very effective insulation for attic rafter insulation requirements. Now, this depends on what thickness you require and how much space you have. Using fiberglass in your attic can allow you to also deck out your attic space to create storage. In addition, sufficient ventilation is necessary for the attic to prevent mold and damp buildup. One has to make sure that there is ample ventilation opening for air to pass between the felt / roof covering and the insulation. Another option for attic spaces is PIR insulation like Kingspan, Celotex, Ecotherm, Quinntherm and Recticel insulation. All of which are rigid board insulation products and come in 1.2m x 2.4m sheets. This type of insulation is more expensive but will give you a better thermal performance than fiberglass, but more on this in another article.

Installing Acoustic Rafter insulation

To begin with the process, one must first understand by evaluating the current condition of the roof or attic. There should be no damp, gaps and air leakage in the finished process and one must make sure that all is in check and possible before the installation begins. There are many insulation solutions to choose from such as – Fiberglass, mineral wool and sheepswool. You will require different amounts of space according to the different types of thermal insulation used. So for example if you use a Knauf Combi-cut roll 200mm thick you will need to have 220mm of space available in your raters as you need a 20mm airflow. However if you do not have this space you could go with a more dense fiberglass insulation like a Knauf Frametherm Roll 35 140mm and this will give you a similar result as the 200mm roll.

Important suggestions before installation –

• Remember to hire registered contractors for the installation process.

• Find out whether the process followed by the contractor is a genuine and systematic process.

• Whether the supplier of the insulation offers installation, delivery and after sales service.

• How long is the installation process going to take?

• How many similar systems have the contractor installed before and try get references?

• What works will be needed to get the attic to its completed condition and whether the contractor will be able to provide the full service?

• Find out whether the company is certified.

How to prevent condensation

Condensation can profoundly affect your home if the attic insulation is not fit correctly. There are many factors that can lead to condensation such as – Increase in humidity, leakage in the roof and imbalance of heat. Frost can build up under your roof sheeting also due to extreme cold temperatures, and one must make sure that the rafter insulation can balance the heat flow.

Insulation4less is the UK’s largest independent online insulation store with the highest customer satisfaction ratings. We supply all the biggest and best brands of insulation direct to the end user and contractor. We supply nationwide with free delivery on all orders over £300.
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