celotex thermaclass cavity wall 21 full fill

Celotex Thermaclass Cavity Wall 21 Insulation

Celotex Insulation Thermaclass cavity wall 21 is a full fill cavity insulation board. This Celotex Insulation board has tongue and grooves. These allow for perfect joining of boards together. Therefore reducing the possibility of heat loss through gaps and the passage of moisture, as is possible with other standard cavity wall insulation boards. Celotex Thermaclass insulation is the latest addition to Celotex’s insulation series of insulation boards. Furthermore it can achieve a super 0.21 W/mK U Value without the need to widen the cavity. In addition it also has the Euroclass ‘E’ rating for reaction to fire according to BS EN 13501-1. Importantly products with this level of classification are not provided with a rating for smoke emission. It has a superb high performance thermal conductivity of 0.021W/m K.

Advantages of installing Celotex Thermaclass Cavity Wall 21

Installing a full fill cavity wall insulation can have a large number of advantages over partial fill. These advantages can include not having to install extra high performance partial fill cavity wall insulation. Another positive affect of installing full fill high grade insulation can be that there is often no need to install very expensive insulation on the internal of the building to get to building regulations. This alone is a major plus side to having Celotex Thermaclass cavity wall 21 insulation as you then gain space on the interior of your property.

Celotex Thermaclass cavity wall 21 is made in 90 , 115 and 140mm thick designed to leave a 10mm residual cavity in most modern cavity wall constructions. These sizes help with installation allowing for such things as mortar squeeze. The installed size of the board is 1190×450 due to the tongue and groove so please allow for this when calculating requirements.

Also when you can get away with not installing insulation to the inside of the external walls you not only save on the insulation materials but also on the labour costs. Finally filling a cavity full of wall insulation can sometimes provide all the insulation you require without the need to extend the cavity width , which would incur greater costs by having to use wider cavity wall lintels and longer wall ties.

Please note this product is not suitable for use in walls over 18m high in England , Wales and 11m high in Scotland. This is due to recent changes to Building Regulations mean that only non-combustible insulation or insulation of limited combustibility can be used in buildings of that height

Buy Celotex Thermaclass insulation at the best prices online

CODE: Thermaclass
SPECIFICATION: 90mm , 115mm ,140mm
SIZE: 1205mm x 465mm


Special offer

Celotex Thermaclass cavity wall 21
6 sheet deal
Size: 1205×465
Thick: 90mm
Only £85.50 + vat
Quote: CELTC90

Special offer

Celotex thermaclass cavity wall 21
4 sheet deal
Size: 1205×465
Thick: 140mm
Only £82.75 + vat
Quote: CELTC140

visit our online store for celotex thermaclass
call us now for full fill cavity insulation

Great service, goods supplied on time , very satisfied

Alan Gibbs

Fantastic Company. Helped with the order from start to finish. Even had an issue my end with the payment and they couldn’t be more helpful.

Mike Reynolds

Good price, good product great service. Thank you

Julie Rhodes,

Ordered online as it was the weekend , recieved a call to arrange delivery day on the Monday morning . all goods arrived in great condition and on the day they said.

Sue Brenner, Holistic regen

Awesome guys sorted me out when i didnt have a clue what to order top geezers

Badders, Holy smoke Vape store

Dont normally leave reviews but they helped me with products through out my selfbuild and saved me a lot of money

Ady Moon, Moon Building

Top Service From quote to delivery can’t get any better thanks

C Lewis, C Lewis Building

Thanks for saving my bacon with next day delivery will be back when I need some more Insulation.

Scott Ainsdale, SA Electrical

Excellent price and delivery what more can i say , keep it up BMD


Very happy with the service we received. Fantastic product at a fantastic price. Cant recommend Jason and the team highly enough. Ordered during Covid-19 when everything was slightly crazy and delayed and Jason called and said they had a lorry in our area so could deliver the very next day! Thank you guys for 5 star service, will be back in the future . All the best, Lacey. Travellers Finds Ltd

Lacey Griffiths, Travellers Finds Ltd

Good for cheap insulation, i bought some celotex from them and it was delivered last week, it was a lot cheaper than anyone else in my area. i’m very happy with this service.

Rav Kumar

Thanks for my order great service

Yanislav Molkiva,

After days of trying to order some Rockwool from suppliers who never got back to me or quoted silly prices, my enquiry to BMD was answered in minutes politely and with clear knowledge of the products and delivery arranged on the phone all at a great price. Top marks for A1 service and product knowledge.

Rich Jenn

As described quick delivery and good condition thankyou

Nick Wilson

Purchsed our floor and wall insulation from this company, they are very helpful and went through the options available to me. after searching about the total price was the best i had so i gave them the order. Deliervy was made in 2 days and everything was fine. I will use them again for the next part of my building project.

James Kergan, JK Building services

Nice to deal with, quick delivery and cheap prices.

Simon Berrinfield

As a small building company we find that BMD will equal or beat our trade depot plus we get free delivery too !!, Also we can get everything in one order and being able to talk to an actual person rather than clicking on a website means we get the service we want. saves time and money whats not to like ? :-)

Clemency Bedford, Bedford Building Maintenance

Excellent company, Jason gave us a really good price and the items were delivered 2 days later much quicker than anyone else could offer. even the delivery driver was incredibly helpful, honestly can’t fault them Jacqui

Jacqueline Jelley,

Ordered Celotex insulation from this company for the first time last week and I will definately be back again. Good price and delivery 2 days later thankyou.


Matt Chapman, MC Construction