Fibreglass Cavity Insulation

Knauf Earthwool Fibreglass cavity wall insulation slabs are a semi – rigid or rigid insulation slab. This fibreglass insulation is designed for use in between brick / block cavity walls, where full fill cavity wall insulation is called for. Fibreglass cavity insulation comes in 1200 mm x 455 mm slabs to fit in with traditional vertical wall tie spacing. Fibreglass cavity slabs come in various densities each giving a different thermal conductivity. These include Dritherm 32 ultimate @ 0.032W/mK which is the top of the range Dritherm insulation. Dritherm 34 super @ 0.034W/mK a mid range cavity wall insulation. Finally the Standard range Dritherm 37 0.037W/mK fibreglass cavity insulation.

Advantages of fibreglass cavity wall insulation

Dritherm cavity wall insulation is easy to install as the fibreglass cavity slabs knit together avoiding any possible air gaps. Fibreglass cavity is also water repellent and environmentally friendly having Zero ozone depletion and a Zero global warming potential. The manufacturing process no longer uses a formaldehyde binder which can make it up to 70% less energy intensive than when the traditional binders are used. In addition it uses a more environmentally friendly bio based material rather than the petroleum based chemical. Importantly Dritherm is approved by the British board of Agrement for use in all exposure zones. All of these Knauf fibreglass cavity insulation materials have excellent fire and thermal qualities.

For any further information or for the best prices on fibreglass insulation please do call our national sales office.


SPECIFICATION: 50mm – 125mm
PRODUCT INFORMATION: Cavity insulation

Special offer
Dritherm 37 Cavity Slab
Thick: 100mm
Only £34.80 + vat
Quote: CAV37-100

Special offer
Dritherm 37 Cavity Slab
Thick: 75mm
Only £18.90 + vat
Quote: CAV37-75

Special offer
Dritherm 32 Cavity Slab
Thick: 100mm
Only £36.50 + vat
Quote: CAV32-100

visit our online store for cavity wall insulation

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,

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

C Lewis, C Lewis Building

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


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

Scott Ainsdale, SA Electrical

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

Badders, Holy smoke Vape store

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

As described quick delivery and good condition thankyou

Nick Wilson

Great service, goods supplied on time , very satisfied

Alan Gibbs

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

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

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

Good price, good product great service. Thank you

Julie Rhodes,

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

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

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

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

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,