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125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)

125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
  • 125mm Unilin XO/SK XtroLiner Sarking Warm Roof Construction (T&G)
  • XO/SK used over the rafters to meet the passive U-Value of 0.15 W/m2K
  • Unilin XO/SK engineered tongue and grooved external roof insulation system
  • Rigid foam modified Polyisocyanurate (PIR) core with textured robust facings
  • Lambda (thermal conductivity) of 0.021 W/mK and Euroclass C s2 d0 fire class
Estimated delivery:
In Stock
£ 562.80
Ex VAT: £ 469.00
  • Brand: Unilin Insulation (UK) known as Xtratherm
  • Model: 125mm Unilin XO/SK Sarking
  • Weight: 36.00kg
  • Dimensions: 2,400mm x 1,200mm x 125mm
  • SKU: 125mm Unilin XO/SK Sarking
  • Product code: P1-3428
  • MPN: 125mm Unilin XO/SK Sarking

Options available

125mm XO/SK Unilin Sarking Roof Board is used over the rafters to meet the passive U-Value of 0.15 W/m2K, an external roof insulation system with robust textured foil facings.

The Xtroliner XO/SK offers a robust continuous layer of insulation, minimising the threat of Thermal Bridging and improving the overall U-Value of the roof.

Using Unilin Xtroliner XO/SK improves detailing, speeds up the installation process and provides a uniform plane to detail more effectively.

Creating a warm roof reduces the normal amount of junctions prone to Thermal Bridging, greatly improving the thermal performance of the roof.

Adding an additional layer of Unilin XO/PR between the counter battens minimises fixing length and improves the overall U-Value of the roof.

Creating a warm roof reduces the normal amount of junctions prone to thermal bridging greatly improving the thermal performance of the roof.

Unilin XO/SK Sarking Insulation Board has a Euroclass C Fire Classification and Compressive Strength of >150 (kPa).




Thickness: 125mm

Width: 1200mm

Length: 2400mm

Size: 125mm x 1200mm x 2400mm

Pack Quantity: 3 sheets

Pack Coverage: 8.64m2

Board Coverage: 2.88m2

Profile: Tongue and Grooved

R-Value: 5.95 m2K/W

Density (Foam Core): 32kg/m3 

Thermal Conductivity: 0.021 W/mK

Compressive Strength: >150 (kPa)

Reaction to Fire: Euroclass C, s2-d0


Unilin XO/SK XtroLiner Sarking (T&G) Board Features:

 · Reduced thermal bridging.

 · Reduced risk of condensation.

 · Lightweight and easy to install.

 · Achieves most efficient U-values.

 · Meets the passive U-Value of 0.15 W/m2K.

 · Euroclass C s2 d0 fire classification.

 · Reduces heat loss in roof construction.

 · Faced with robust aluminum foil facings.

 · Improves detailing, speeds up the installation process.

 · Rigid foam modified Polyisocyanurate (PIR) core.

 · Compressive Strength >150kP (at 10% compression).

 · Declared lambda (thermal conductivity) of 0.021 W/mK.

 · Engineered tongue and grooved external roof insulation system.


Unilin Xtroliner XO/SK Sarking Warm Roof (T&G) Installation Guidelines:

 · Ensure cavity wall insulation has continued to roof height to meet with the roof insulation.

 · Fix a treated timber stop rail to the end of the rafter at the eaves.

 · Lay XO/SK over the rafters ensuring the tongued and grooved edges of the boards are fully engaged and positioned in a staggered pattern.

 · Joints should be fully supported by rafters.

 · Fill any gaps with expanding foam.

 · Use large headed clout nails to hold boards temporarily in place until they are secured by the counter battens.

 · Fix 38mm x 50mm counter battens with approved helical type fixings through the XO/SK into the rafter.

 · The amount of fixings is determined by the fixing manufacturer who can also provide wind load calculations.

 · A breathable sarking membrane should be fitted; refer to manufacturer’s Agrément certification.

 · Ventilation may have to be provided subject to that certification and minimises the risk of interstitial condensation forming on the underside of the membrane.

 · Providing an unventilated void under the membrane can improve thermal performance.

 · Secure 50mm x 25mm tiling battens through the counterbatten and XO/SK to the rafter.

 · If an additional layer of insulation is required, Xtroliner Pitched Roof can be fixed between the rafters.

 · Cut XO/PR with fine toothed saw to fit tightly between rafters, flush with the top of the rafter.

 · Allow slight oversize of cut to achieve ‘friction fit’ and seal any gaps with expanding foam.

 · Provide a separate vapour control layer to the warm side of the insulation.

 · Finish with plasterboard fixed with drylining screws.

 · Screw fix every 150mm, 12mm from edge of boards, ensuring a minimum 25mm penetration into the rafter or alternatively follow plasterboard manufacturer installations guidance.


*Further information may be found in our Downloads section.

Fairly easy access to all PDF files.

Datasheet ǀ Declaration of Performance - DoP ǀ BBA Certificate ǀ Installation Guide ǀ Certificates ǀ Brochure ǀ SPEC Sheet 

*Special Product - Non returnable cancelable.

Board covarage 8.64 m2
Colour Light yellow
Density 32 Kg/m3
Length 2400mm
Material Polyisocyanurate Rigid Foam
Pack Coverage 8.64m2
Pack Quantity 3 boards
Profile Tongue and Grooved
R-Value 5.95 m2K/W
Size 125mm x 1200mm x 2400mm
Thermal Conductivity 0.021 W/mK
Thickness 125mm
Width 1200mm
Fire Reaction Euroclass C, s2-d0
Coverage 2.88m2
Finish Embossed aluminum foil facings
Quantity 3 sheets
Shipping method Articulated Vehicle ǀ Courier
Applications External Roof Insulation Systems
BBA Certified Yes (No. 12/4956)
Fixing method Over the rafters
Foil faced Yes, foil facings on both sides
ETA Notification Yes
U-value 0.11 - 0.20 W/m²K
Features Meets the passive U-Value of 0.15 W/m2K
Manufacturer Unilin Insulation®

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We deliver insulation materials to Mainland UK only. Deliveries to Highlands, Northern Ireland, Isle of Wight etc.. might be possible at additional cost.
We offer free delivery on most of the orders above £300 (excluding VAT) (except special products - shipping cost via courier - products marked ''Request A Quote'')

Delivery of some insulation materials might be extended due to the current situation (Covid-19, stock shortages, allocations).
If you need materials quickly please contact us - we will do our best to help you source materials needed.

We do not deliver on weekends and bank holidays. Sometimes we can deliver on Saturdays - please check with us before placing the order.
If you need any further information please contact us tel. 02081910776

We can help to calculate price per m2 or linear meter (one meter in length) cost, please just contact us via phone 02081910776, email or live chat. Alternatively, you can work it out yourself quickly and easily: to get cost per meter square please divide price shown in orange area by ''Required area (m2)'' Example price of £28.80 divided by board coverage 2.88m2 = cost of £10.00 per m2.


No matter whether you choose a local installer or a national company, there’s a few tips to help you find the right installer for your home insulation improvements, such as asking for recommendations and making sure that they’re part of a certification scheme. This makes sure that they have the right skills and standards of workmanship to carry out the installation, and you can be sure that they know exactly what they are doing.


1. Thermal inspection picture in portfolio

It’s worth seeing a installer’s previous work. There’s no harm asking if you can see any properties nearby that they’ve installed insulation in. Best way would be to see Infrared Thermal Imaging Inspections. Thermal cameras spot small, but key changes in temperature in different areas of a house, identifying problematic areas that the human eye never could and some that a visual inspection could only hypothesize.

2. Reviews

Along with checking recommendations and previous work, finding reviews online can often be a great way to find out if they provide a good service or not. However, it’s best not to solely rely on reviews you may find or review websites, as there’s no controlling who writes them.

3. Compare prices

Comparing prices will also ensure companies can’t take advantage of you and give you a fair price. 

4. Word of Mouth

The best way to find a great insulation installer is through recommendations. Make sure you ask friends and family. They will most likely give you their honest opinion and can tell you from first hand experience.


Whether you require a wall, cladding, external wall, loft or floor insulation fitted, you can find and hire your local insulation installers from popular UK web pages. A simple internet search will return thousands of potential installers near your area.



We are the stockist of construction materials and related products for both trade and DIY from most recognizable brands in the UK like Cordek, RCM, Promat, Rockwool, Isover, Celotex, Xtratherm, Ursa, Low-E, Cedral, Kingspan, Dufaylite, British Gypsum, K-rend, Ecotherm, Iko enertherm, Kay-Metzeler, Terrawool to allow you to complete your insulation job on time at competitive prices and the highest standards.


Whether you are a large company or a DIYer, if you need a large amount of insulation materials, we can offer quantity discounts at the best prices. Please contact us and our friendly customer service will try to find the best and cheapest solutions for you. We value your time and we will try to deliver the products as soon as possible at a reasonable price to your construction site or house. The UK's leading insulation supplier near you and your needs. Price List available upon request.
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
125mm XO/SK T&G Unilin Warm Roof Insulation Board (pack of 3)
£ 562.80