Internal Corner Cavity Full Fill Wall PIR Insulation 125mm
€71.60 (Inc. VAT)
Key features:
- High quality PIR Insulation
- Trusted brand
- Internal Corner – 125mm and 2.16 sqm coverage
- Ideal for Trades people and for DIY
- Unilin was previously known as Xtratherm
5 in stock (can be backordered)
Product Description
Unilin (previously Xtratherm) CavityTherm is a continuous wall insulation system delivering exceptional thermal performance with built-in wind-driven rain protection. It is a high-performance PIR composite board with a lambda value of 0.021 W/mK, designed for full-fill cavity wall applications. The gas-tight facings and profiled HIPS skin create a drainage plane to manage moisture.
Key Features
- Engineered HIPS facer for rain protection
- Redirects moisture to the outer surface
- Prepositioned slots for sloping wall ties—no creep
- Fully engineered jointing for a tight fit
- Full accessory range for a continuous system
- Excellent thermal bridging values
- Continuous insulation layer
- Minimal cavity width requirement
- No engineer’s report needed
- Achieves ultimate U-values & meets standards
Thermal Performance
- Thermal Conductivity: 0.021 W/mK (BS EN 13165:2008)
- Typical R-Value (125mm): 5.71
- Total Coverage: 2.16m²
Advanced Moisture Protection
CavityTherm’s engineered profiled facing ensures any moisture penetrating the external wall is redirected back onto the outer leaf. The rebated edge detailing on all four edges interlocks tightly, ensuring excellent thermal bridging detailing and system continuity.
Typical Physical Characteristics
- Density: 30 kg/m³
- Compressive Strength: >100 kPa @ 10%
- Service Temperature: -20°C to +100°C
Smart Design for Easy Installation
The profiled edge allows wall ties to slope down to the outer skin, acting as a template for mortar on the inner skin. The gas-tight facings and drainage plane provide additional moisture protection.
Energy Efficiency & Sustainability
CavityTherm achieves U-values aligned with Code for Sustainable Homes targets, enabling architects to design low-carbon homes while maintaining a 100mm cavity width. It meets A+ and Passive standards, making it a practical and cost-effective choice for energy-efficient wall insulation.
More Information
- See the Product Brochure and Installation Guide here
- See the Agrément Certificate here
- See the Specification Clause here
- See the Declaration of Performance here
For large volume orders, call 0818 888 000 or use our live chat for a custom quotation.
Frequently asked questions:
What is CavityTherm?
CavityTherm is a high-performance PIR insulation board (λ = 0.021 W/mK) with gas-tight facings. One side features a profiled HIPS skin to channel moisture away. Rebated edges ensure a secure fit.
What are the benefits of using CavityTherm?
CavityTherm achieves Passive House U-values in a 150mm cavity, ensuring thermal continuity for a cost-effective, low-energy build.
What wall ties should I use with CavityTherm?
Standard stainless steel wire wall ties (up to 5 ties/m²) are suitable. Low conductivity ties may be needed for wider cavities, but they can increase thermal bridging at junctions.
Why should wall ties slope downward?
All wall ties, regardless of insulation type, should slope slightly downward to prevent water from tracking into the structure.
What thicknesses are available?
CavityTherm comes in 100mm, 125mm, and 150mm, achieving U-values as low as 0.12 W/m²K.
What types of buildings can use CavityTherm?
It is suitable for masonry cavity walls in domestic and non-domestic buildings up to 25m high.
What accessories are available?
Xtratherm provides bespoke insulated pieces to prevent thermal bridging around vents, cavity trays, corners, and meter boxes.
Why does CavityTherm have engineered edge detailing?
It ensures continuous insulation, avoids gaps, and prevents the 0.01 U-value penalty required by BR443 calculations.
How do I seal cut boards?
- Remove profiled edges, butt boards tightly, and seal.
- Inner leaf first? Use waterproof tape on dry surfaces.
- Building from inside? Apply self-adhesive jointing strip.
- Services through insulation? Slope them outward and dress DPCs over services per Eurocode 6.
What is a cavity board, and why use it?
A cavity board catches mortar drops during construction, preventing buildup. HIPS skin on CavityTherm is easily cleaned with a damp cloth.
Delivery Information:
- Note: Delivery of this bulky product is available Nationwide but will be subject to a bulk delivery charge. Delivery charges are calculated during checkout according to the delivery address provided.
For large volume orders, we may offer better delivery rates—call 0818 888 000 to discuss pricing.
Delivery charge information:
You can add any and all products to the basket and calculate your delivery charges easily. Simply enter your Eir Code and all applicable charges will be calculated automatically.
- Orders of €150 inc VAT or over will get free delivery nationwide. (Please see notes below for exceptions)
- All orders under €150 inc VAT incur a standard delivery charge of €10 including VAT
- (Please see below for exceptions)
- We deliver to anywhere in Ireland.
Bulky items:
Bulky items may incur delivery surcharges (see below) as extra courier costs unfortunately are often unavoidable. If the order is over €150 only the bulk delivery charge will apply. The final delivery charge for bulky products will be calculated when all items have been added to the shopping cart.
All efforts are made to indicate where products are subject to delivery surcharges.
Special Order items:
We are in regular contact with our suppliers and we try our best to make sure that all “special order items” on our webstore are available from our suppliers within the timeframe advertised. If, for some reason our supplier is out of stock and you have ordered the product we will let you know immediately and give you the option to either wait until it’s back in, upgrade to a better model at little or no extra cost or receive a full refund. See more info on Special Order products here.
Timeframe:
All nationwide deliveries will be delivered within 2-3 working days.
(Local deliveries within 1-2 working days.)
Special order items may take longer to deliver but this will be indicated on the product information page. You can see more info on Special Order products here.
Working days are Monday through Friday excluding public holidays. Orders placed on Saturday/Sunday will be deemed as being placed on the following Monday.
Some items may take longer to ship. If this is the case, we will notify you by phone/email of this delay.
If your delivery is urgent please contact us by phone or email and we will do our best to expedite it.
Please indicate on your order any specific delivery instructions.
Bulky goods:
Bulky goods will be delivered on pallets and will be unloaded by the courier. All bulky goods are delivered kerbside. Unfortunately, the delivery company will not convey the goods into premises for storage unless agreed in advance. Access to the delivery location must be suitable for a truck and failure to provide suitable level ground for operating pallet truck may result in refusal to deliver by the courier. Please note delivery operators will apply safe procedures in relation to ongoing Public Health considerations..
Exceptional Goods:
Some building materials are extremely bulky and not practical to deliver outside Co. Sligo e.g. concrete blocks, tonne bags of sand or gravel or some lengths of timber. We have highlighted where this is the case in bold red writing. If you do order these products we will contact you to see if you want to pay an additional delivery charge or if you wish to cancel the order. Please do not take offence to this as some bulky goods may cost much more to deliver than the value of the goods. We are based in Sligo so can offer a local delivery service in this area using our own vehicles.
If there is a forklift or teleporter available onsite, we would appreciate if you could tell us in advance by filling out the special delivery notes when completing the order.
The Seller or the courier company will not be held responsible for any damage to goods or persons caused by the goods being unloaded by the buyer.
**Please contact us in advance of ordering if unsure of the above**
Damaged goods:
Where goods are damaged on delivery the Buyer has the right to refuse delivery. Damaged goods should be photographed on delivery and photos emailed to sales@mybuildingsupplies.ie straight away. If goods are damaged on delivery, we will replace the goods in as timely a manner as possible at no extra cost.
Once the goods are signed for it will be deemed that goods were in good state when delivered.
General:
Delivery shall be within a time period agreed between the Buyer and Seller and the Seller shall use its best endeavours to ensure that delivery takes place within the period agreed. Failure by the Seller to deliver the Goods within the agreed time period shall not amount to a breach of this contract by the Seller and the Buyer shall not be entitled to damages or other compensation or to cancel this contact by reason of such failure.
The Seller reserves the right to deliver in instalments. Each part delivery shall be deemed to constitute a separate contract, the fulfilment or non-fulfilment of which shall not affect any other part of the contract or the contract as a whole. Where any order involves more than one delivery and default is made on payment on the due date (either under this contract or any other contract made between the Seller and the Buyer) the Seller shall have the right to suspend all further deliveries until payment is made or to terminate the contract without prejudice to any existing claim.
The Seller shall not be liable to the Buyer for any loss or damage which may be suffered by the Buyer as a direct or indirect result of the supply of the Goods by the Seller being prevented, hindered or delayed by reason of any circumstances whatsoever which are outside the control of the Seller. Once delivery has been accepted the Buyer shall not be entitled to withhold or postpone payment of all or any portion of the price agreed, therefore.
1. Where goods are damaged on delivery the Buyer has the right to refuse delivery. Damaged goods should be photographed on delivery and photos emailed to sales@mybuildingsupplies.ie. If goods are damaged on delivery, we will replace the goods in as timely a manner as possible at no extra cost.
2. If goods are signed for and later found to be faulty/damaged, notice must be given in writing within 24 hours and photos will be required to be emailed to sales@mybuildingsupplies.ie.
3. All faulty/damaged goods issues will be dealt with on a case by case basis and best endeavours will be made to rectify within a timely manner. Manufacturers’ warranties will apply in certain cases.
4. Any returned items which are not faulty or damaged will incur full carriage costs which must be paid for by the customer. Notice of intention to return unwanted goods must be given within 14 days of receiving goods. Returned goods must be in original packaging and in original condition before refunds can be given.
5. All returned goods to be sent to Patrick Rogers Ltd., O’Connell St., Ballymote, Co. Sligo
Note regarding Oil Boilers and Boiler stoves:
Please ensure you check with us first or consult a qualified professional before ordering your oil boiler or boiler stove to ensure you order the correct one for your home. If the product needs to be returned a restocking fee may apply.
Returns of Special Order Items
All “special order items” are subject to the same product returns policy as stocked items. However, items which are returned that are not faulty or damaged on delivery will be subject to a 10% restocking fee.
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