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Celotex Thermaclass Cavity Wall 21 is a highly efficient and reliable form of cavity board insulation. It is manufactured by Celotex with a unique tongue and groove technology, providing an airtight seal between the boards and the existing cavity wall.
The PIR board for full-fill masonry cavity walls also features a unique shape which allows it to fit snugly into the cavity pir, ensuring that no heat can escape through gaps or other openings. This helps to maintain a consistent temperature in the home, reducing energy bills considerably.
Some major benefits of Celotex Thermaclass Cavity Wall 21 include:
Thermal Insulation: Outstanding heat retention with a thermal conductivity or K-Value of just about 0.021 W/m.K, this cavity PIR board gives an exceptional thermal performance at a reduced thickness and helps hit the desired U-value.
Thanks to its unique T&G profiling this cavity board gives a full-fill solution with no residual spacings that would otherwise lead to losing heat. With its low-emissivity foil facings, this PIR cavity board further enhances thermal insulation in cavity walls.
Foil-Facings: A foil facing with low emissivity gives enhanced thermal performance in sealed air cavities, contributing to an upgraded U-value (with a residual space of 10mm).
Easy to Install: Celotex cavity PIR insulation helps insulation to maximise thermal performance with its unique tongue and groove joint profile. It is a lightweight cavity wall insulation board made of polyisocyanurate or PIR.
It is perfectly sized to fit standard cavity wall tie spacing. The rigid PIR board form a continuous layer of insulation in cavity walls.
In addition to its excellent thermal efficiency, Celotex Thermaclass Cavity Wall 21 requires minimal preparation time. The insulation board has a tongue and groove joint for easy assembly and can be easily cut to size using a knife or saw, requiring no specialist tools or skills.
BBA Approved: Celotex Thermaclass Cavity Wall 21 is full-fill cavity insulation approved by BBA. Care must be taken to install, use and maintain these insulation boards as set out in the certificate.
Moisture-Resistant: Polyisocyanurate insulation resists moisture ingress. In addition, the foil-facings on the PIR boards also function as a moisture barrier, thereby completely protecting cavity walls from moisture, condensation and moulds
Product Details
| Thickness | Length | Width | Boards / Pack | Pack Coverage |
| 90mm | 1190 | 450 | 6 | 3.21 |
| 115mm | 1190 | 450 | 5 | 2.675 |
Key Features:
- Celotex Thermaclass Cavity Wall 21 gives superior thermal performance with a K-value of just 0.021 W/m.K.
- Its unique tongue and groove profiling enables easy installation. Lightweight cavity boards
- This 90mm Celotex thermal class cavity wall insulation ensures a continuous layer of insulation and moisture protection.
- With their low-emissivity foil facings, they reflect radiant heat and enhance thermal performance in cavity walls.
- BBA approved for tension-free cavity walls.
Applications:
Celotex cavity wall insulation is ideal for use in retrofit cavity wall insulation projects as well as new builds. With its engineered tongue and groove joint it is ideal for Full Fill Masonry Cavity Wall insulation.
- One Cavity PIR board is 1190 x 450mm in dimension
- Thickness available - 90mm and 115mm
- Tongue and groove profiling for easy installation and improved thermal performance.
- Dual Foil Facing Celotex cavity boards for masonry full-fill cavity wall insulation or 10mm residual cavity gap.
- Lowest K-value of 0.021 W/m.K, for improved energy savings
- BBA-certified cavity wall insulation
- Fire Euroclass E Reaction to Fire classification, according to BS EN 13501-1.
| Insulation Type | Cavity Wall Insulation |
| Brand | Celotex |
| Length | 1190mm |
| Width | 450mm |
| Thickness | 90mm and 115mm |
| Boards/Pack | 6 (90mm), 5 (115mm) |
| Pack Coverage | 3.21 Sq.m (90mm), 2.675 Sq.m (115mm) |
| Thermal Conductivity | 0.021 W/m.K |
| R-Value | 4.25 (m².K/W) |
| Fire Classification | Euroclass E Reaction to Fire classification |
| Application | Full-fill masonry cavity wall insulation |
| Lead Time | Please call for lead times. Non-stock Item in some warehouses |
| Free Collections Available |
|---|
| Save on delivery charges and collect the order for free from a warehouse near you. Just choose the In-Store Pickup option at the checkout or call: 03303130245 |
| Free pick-up locations include - Warrington, Wolverhampton, Gatwick, Bedford, Ipswich, Glasgow, Newcastle, Leeds, Chesterfield and Bridgewater. |
| Delivery Terms | |
|---|---|
| Order Value (Excluding VAT) | Delivery Charge (Excluding VAT) |
| Above £370 | Free Delivery |
| Up To £370 | £50 |
Returns/Refunds And Cancellations:
You can cancel your order and get a full refund before we confirm your order via email. Orders cancelled after the order confirmation email is sent, may attract a restocking fee.
PIR insulation can be returned, provided they are in a resalable condition within 30 days from the date of receipt. Please contact us via email and we will assist you accordingly.
For more information on returns of faulty/damaged products and deliveries, please refer to our delivery information page.
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Introducing Celotex Thermaclass Cavity Wall 21
Thermaclass Cavity Wall 21, an outstanding polyisocyanurate (PIR) insulation board, is designed specifically for full fill cavity wall applications. It showcases exceptional thermal performance (0.021 W/m.K) and features a low emissivity foil facing. This product can be installed with a residual cavity of up to 10mm to aid in installation and accommodate mortar squeeze, or it can serve as a comprehensive full fill solution with no residual cavity.
Thermaclass Cavity Insulation Product Features
Lightweight and compact, the Thermaclass Cavity Wall 21 boards measure 1190 x 450mm when installed and possess a unique tongue and groove edge profile, contributing to a more secure fit. A low emissivity foil facing is another crucial feature of this insulation board, contributing to its thermal performance.
These Rigid PIR full fill cavity insulation boards are BBA-approved, with certificate 16/5343 for full-fill cavity walls. In terms of fire classification, the product adheres to the Euroclass E Reaction to Fire classification, as defined by BS EN 13501-1.
Celotex Thermaclass Cavity Insulation Product Specifications
Thermaclass Cavity Wall 21 is available in a range of thicknesses, each with identical length and width dimensions. The boards' maximum weight varies depending on their thickness.
| Thickness (mm) | Lambda Value (W/m.K) | R-Value (m².K/W) | Length (mm) - Net/Installed | Width (mm) - Net/Installed | Maximum Weight (kg/m²) | Pieces per Pallet Gross |
| 90 | 0.021 | 4.25 | 1205/1190 | 465/450 | 2.80 | 96 |
| 115 | 0.021 | 5.45 | 1205/1190 | 465/450 | 3.55 | 80 |
| 140 | 0.021 | 6.65 | 1205/1190 | 465/450 | 4.30 | 64 |
Image Credit : Saint Gobain / Celotex Thermaclass Cavity Wall 21 Installation Guide
Benefits of Thermaclass Cavity Wall 21
- Thermal Performance: The insulation board delivers superior thermal performance with a conductivity of 0.021 W/m.K, reducing the insulation thickness required to reach the target U-value.
- High-Performance Facer: The low emissivity foil facing enhances thermal performance in sealed cavity air spaces, thereby improving the achievable U-value (assuming a residual cavity of 10mm).
- Easy to Install: The boards fit standard cavity wall tie spacing and are lightweight and rigid, facilitating transportation, handling, and installation.
- BBA Certification: Thermaclass Cavity Wall 21 has been evaluated by the BBA and deemed suitable for defined full fill cavity wall applications when installed, used, and maintained in accordance with the certificate.
Important Guidelines
Before utilising Thermaclass 21, ensure that its use complies with all relevant national Building Regulations and guidance, as well as local, national, and other applicable standards for your construction or application, including fire and applicable height restrictions.
Thermaclass Cavity Wall 21 should not be used in the external walls of buildings taller than 11 metres. According to recent updates to Building Regulations, only non-combustible insulation or insulation of limited combustibility should be used in buildings of this height.
How to Install Thermaclass Cavity Insulation
1. Start by assembling the first segment of the inner leaf of the wall.
2. Following this, position the initial row of wall ties at least one level of blockwork beneath the Damp Proof Course (DPC), as detailed in Eurocode 6, BS EN 845-1, and the Building Regulations Approved Document A, which provide further guidance on wall ties and masonry wall construction.
3. You'll then need to position the Thermaclass Cavity Wall 21 boards with the tongue at the top. In the planning stage, decide whether the tongue should be positioned on the 'top and left' or 'top and right' of the boards and stick to this orientation throughout the installation process.
Take note, this might lead to some boards having the branded foil facer facing outward, while others will display the unbranded one. This isn't a problem as both facers perform equally.
4. Prior to fitting the Thermaclass Cavity Wall 21 insulation board, make sure to: a. Pinpoint where the wall ties will land on the tongue side of the board. b. Use a self-retracting knife to cut the facer and then employ a sharp specialist insulation saw to make the final small incision in the tongue profile.
The cut should be angled to follow the direction from the inner leaf to the outer leaf. c. Ensure the incision is no deeper than 15mm. d. If a residual cavity is present, all ties should incorporate a retaining clip or disc to secure the boards against the internal wall leaf.
Image Credit : Saint Gobain / Celotex Thermaclass Cavity Wall 21 Installation Guide
5. The initial row of the Thermaclass Cavity Wall 21 insulation boards should be supported by the first row of wall ties. The boards should fit flush against the inner leaf, leaving up to a 10mm residual cavity where specified, between the insulation board and the outer leaf of the wall.
Boards should be installed either as per the engineer's requirement or at least 150mm below the DPC to provide edge insulation to the floor and lessen thermal bridging at this intersection. Take care to ensure the Thermaclass Cavity Wall 21 insulation boards do not touch the ground and that all board edges are sealed.
6. Subsequent boards should be fitted snugly against the previous one by joining the tongue and groove edges together. This process should be repeated for the first row of boards.
7. When installing further rows, maintain a staggered pattern to avoid continuous vertical joints – a 600mm staggering pattern is recommended. The position of the wall tie should not coincide with a vertical joint. More information on starting the staggering pattern in corners can be found in section 11.
8. Keep constructing the cavity wall and installing insulation by following the previously outlined steps. Make sure to remove any excess mortar from the cavity face and use a cavity board to prevent mortar from falling onto the top edge of the insulation.
9. In instances where installation of the insulation boards stops below the wall's highest point, the top edge of the insulation should be shielded by a cavity tray. Alternate perpend joints should be raked out to facilitate adequate water drainage from the tray.
10. Exercise care to avoid: a. Any damage to the board during installation. b. Puncturing the foil facing of the insulation board with the wall tie, as this can allow moisture ingress. Any damaged boards should be replaced.
Image Credit : Saint Gobain / Celotex Thermaclass Cavity Wall 21 Installation Guide
11. Installation around corners should take place as follows, as demonstrated in Figures 4, 5 & 6:
Position boards in a 'blocking' arrangement to ensure staggered corner edge joints. If the board's tongue is exposed at the corner edge, remove it using a sharp specialist insulation saw or insulation knife. There's no need to alter the board's groove when it is exposed at the corner edge.
The boards at the corner should be butt-jointed. All presenting edges must be flush-cut by removing the groove or tongue at the very least. Make sure all cuts are precise to ensure all edges are butted tightly with no air gaps, achieving continuity of the thermal envelope around the corners.
For boards that 'interlock' in the blocking arrangement, cut and remove a section of the tongue at the top of the lower board to ensure a flush fit with the board above. - Use a sharp specialist insulation saw or insulation knife to score the top of the tongue on board A by lining it up with the tongue edges and right-hand edge of board B. - Cut through the tongue of board A and remove the sections of the tongue, leaving a 'residual rectangle' of tongue.
Note that the cuts will have to be angled to reflect the tapered shape of the tongue. - This allows the overlapping tongue and groove edges of the upper and lower boards to fit flushly at the corner junction. In positioning the corner boards in a blocking arrangement, it's crucial to maintain the staggered pattern to avoid vertical joints on each row. Corner boards should be cut to size where necessary, taking into account the butt-joint, to achieve this.
Note that all corners should incorporate a vertical sealed or self-adhesive DPC with a minimum 100mm overlap beyond the board ends at all courses. The width of the DPC should be chosen based on the thickness of the board being installed. Wall ties in corner details should be positioned in accordance with the engineer’s specifications or Eurocode 6, BS EN 845-1 and Building Regulations Approved Document A.
Installing Thermaclass Cavity Wall 21 insulation boards around openings requires the tongue and groove edge to be trimmed using a sharp specialist insulation saw or insulation knife. Ensure that the tongue edge is cut accurately to form a tight butt edge at the opening interfaces. Boards should be cut precisely and the cut pieces should be accurately and securely fitted to fill the space entirely. Around openings, appropriate damp proofing should be used as per regulations, and any moisture should be directed to the external face of the building.
When handling and installing the boards, always wear eye protection and face masks. Gloves should be worn when cutting boards or handling cut ones. Avoid sliding bare hands along board edges as aluminium foil edges may be sharp. If dust or particles get into your eyes, rinse with liberal quantities of water. Apply a barrier cream to exposed skin areas before handling, if your skin is sensitive to fibre irritation. Ensure your site conditions are well-ventilated.
12. The positioning of wall ties around openings should be in accordance with the engineer's specifications or Eurocode 6, BS EN 845-1 and Building Regulations Approved Document A. Take care not to damage boards~
Why use Thermaclass for full fill cavity insulation applications?
Geared for full fill cavity wall applications, Thermaclass Cavity Wall 21 is an insulation board that simplifies the installation process. It's designed to facilitate the inclusion of a residual cavity of up to 10mm to enhance installation ease and cater to mortar squeeze, or it can serve as a comprehensive fill solution without any residual cavity. Notably, the sizing of these boards aligns seamlessly with standard cavity wall tie spacing, removing the need for tedious cutting and resizing.
In essence, full fill cavity wall insulation utilises a larger portion of the space within the cavity formed by the structure's inner and outer leaf. By doing so, it effectively bolsters the insulation of the structure, all without demanding an expansion of the wall width. This approach retains more internal space within the property, maximising area efficiency.
Notable Differences between Thermaclass and Celotex Cavity Batts (CW4000)
When comparing Thermaclass 21 and Celotex Cavity Wall Boards (CW4000): what sets them apart? Primarily, the distinguishing feature is their design orientation. Cavity wall boards, or CW4000, present a straight edge and offer thicknesses ranging from 40mm to 100mm. In contrast, Thermaclass 21 showcases a tongue and groove edge and supplies thicker boards, with thicknesses spanning from 90mm to 140mm.
Moreover, while CW4000 is intended for partial fill applications, Thermaclass 21 is crafted for full fill applications. Their thermal conductivity also diverges, with CW4000 having a thermal conductivity of 0.022W/mK, while Thermaclass 21 surpasses it with a lower thermal conductivity of 0.021W/mK.
Among the Thermaclass 21 Cavity Wall insulation board options, the 90mm board has gained recognition as the top seller. Lots of customers frequently opt for 90mm Thermaclass boards, as the 90mm board strikes the right balance of meeting insulation requirements without encroaching excessively on the internal space.
Supplementary Information
Thermaclass Cavity Wall 21 has a declared thermal conductivity of 0.021 W/m.K as per BS EN 13165 for factory-made rigid polyurethane foam (PU) products. The product also carries the UKCA Mark in compliance with BS EN 13165.
All Thermaclass products, including Cavity Wall 21, are manufactured under an Environmental Management System complying with ISO 14001:2015, reflecting the company's commitment to sustainability.
For additional information on the handling, storage, and health and safety guidelines related to Thermaclass products, please visit insulation-uk.com/healthandsafety. For details on Thermaclass Cavity Wall 21 installation, refer to www.insulationuk.com/thermaclass-cavity-wall-21
Conclusion
In conclusion, Thermaclass Cavity Wall 21 is a high-performance, cost-effective, and practical solution for full fill cavity wall applications. Its comprehensive set of benefits and impressive features make it a preferred choice for optimising insulation while ensuring excellent value for money.
When it comes to 90mm cavity wall insulation, Thermaclass is a stand out performer and one of the best sellers amongst all our Celotex Boards and any 90mm full fill cavity on the market.
Q: What are 90mm Celotex Cavity Batts?
A: The 90mm Celotex Thermaclass Cavity Wall 21 is a high-performance polyisocyanurate or PIR full fill cavity wall insulation board. It features a foil facing to each side and is designed to provide excellent thermal performance when installed in cavity wall applications.
Q: What are some of the product benefits of 90mm Celotex Thermaclass Cavity Wall 21?
A: Some product benefits include high thermal performance, zero ozone depletion potential, and a low global warming potential. The boards are light and rigid, making them easy to install, while the engineered tongue and groove edges help ensure a continuous layer of insulation for maximum energy efficiency.
Q: What size are Celotex 90mm insulation boards?
A: The 90mm Celotex Thermaclass Cavity Wall 21 comes in two sizes: 1200mm x 450mm and 1190mm x 450mm. Both sizes have been specifically designed for a secure and tight fit, helping to improve the product's overall thermal performance.
Q: Can 90mm Celotex Thermaclass 21 be used in all cavity wall applications?
A: The product has been assessed by the British Board of Agrément (BBA) as fit for use in defined full fill cavity wall applications, including in sealed cavities. Its specific dimensions make it highly suitable for these types of applications.
Q: What is the difference between the 1200mm x 450mm and 1190mm x 450mm 90mm Celotex Thermaclass Cavity Wall 21?
A: The difference between the 1200mm x 450mm and 1190mm x 450mm sizes of 90mm Celotex Thermaclass Cavity Wall 21 insulation board is essentially down to the fitting dimensions.
The insulation board's gross size (before installation) is 1200mm x 450mm, which includes the tongue and groove edge profile. Once installed, these tongue and groove edges interlock, effectively reducing the dimensions of the insulation board to a net size of 1190mm x 450mm.
This interlocking design plays a vital role in eliminating gaps between the boards, enhancing the overall thermal performance and making the insulation more effective. So, while the insulation boards are manufactured to be 1200mm x 450mm, once fitted properly, they take up a space of 1190mm x 450mm.
Q: Why is it important that the product has been assessed by the BBA?
A: Assessment by the BBA means that the product's quality, safety, reliability and if installed correctly, durability, have been thoroughly tested and approved. This certification provides assurance to users that the product is fit for use in specified applications and meets all related building standards.
Q: What does the engineered tongue and groove mean?
A: The engineered tongue and groove refers to the design of the board's edges. This feature enables the boards to interlock, making it easier to install and helping to ensure a continuous layer of insulation. As a result, the boards help to maximise thermal performance and therefore energy efficiency in a building.
Q: How easy is it to install 90mm Celotex Cavity Insulation?
A: The boards are light and rigid, making them relatively easy to handle and install. The engineered tongue and groove feature of the boards further facilitates a seamless installation process.
Q: How does Thermaclass contribute to environmental sustainability?
A: The product contributes to environmental sustainability in several ways. It has a high thermal performance, resulting in better energy efficiency and reduced energy usage in a building. Additionally, the product has zero ozone depletion potential and a low global warming potential.
Q: What is Celotex Thermaclass Cavity Wall?
A: The 90mm Celotex Thermaclass Cavity Wall 21 is a high performance polyisocyanurate (PIR) product meant for insulation purposes. It features an engineered tongue and foil facing on each side, offering excellent thermal performance in cavity wall applications. The dimensions of these light and rigid boards are 1200mm x 450mm.
Q: What are some of the product benefits of 90mm Celotex Thermaclass Cavity Wall 21?
A: The product offers high thermal performance, improved thermal insulation due to foil facings on either side, and is designed to ensure continuous layer of insulation maximizing efficiency. It has low global warming potential and zero ozone depletion potential, making it an environmentally friendly option.
Q: Can 90mm Celotex Thermaclass Cavity Wall 21 be used in defined full fill cavity wall applications if installed correctly?
A: Yes, the 90mm Celotex Thermaclass Cavity Wall 21 has been assessed by the BBA as fit for use in defined full fill cavity wall applications when installed correctly. Please read the certification for the exact installation guidelines.
Q: What are the sizes of the 90mm Celotex Thermaclass Cavity Wall Insulation?
A: The typical sizes for the 90mm Celotex Thermaclass Cavity Wall are 1200mm x 450mm, and are specially sized to fit between common wall tie spacing. Remember to keep a 10mm residual cavity to satisfy the recommendations of the Building Regulations and protect from wind driven rain.
Q: What certification does 90mm Celotex Thermaclass Cavity Wall 21 have?
A: The 90mm Celotex Thermaclass Cavity Wall 21 has been assessed by the British Board of Agrément (BBA) and is fit for use, as per the BBA guidelines. For detailed information, please read the certification in the product package.
Q: Can Celotex Thermaclass be used as a full cavity or as a full layer of insulation?
A: Yes, you can choose to install the Celotex Thermaclass 90mm as full cavity insulation or to maximise the layer of insulation depending on your requirements and the application.
Q: How does Celotex Thermaclass Cavity Wall 21 contribute to environmental protection?
A: The 90mm Celotex Thermaclass Cavity Wall 21 has a low global warming potential and zero ozone depletion potential. This means it is a product that is not only efficient but also environmentally friendly by helping to reduce harmful emissions and contributing to environmental protection.
Q: How are Celotex Thermaclass Cavity Wall 21 boards in terms of ease of installation?
A: Celotex Thermaclass Cavity Wall 21 rigid board insulation is light, rigid, and has been sized to fit standard wall tie spacing, aiding ease of installation. The boards also feature an engineered tongue and groove edge profile, helping to ensure a continuous layer of insulation and further enhancing the ease of installation.
