From £21.39 + VAT per bag

Cavity fill insulation – Cemwood CW1000

Cemwood CW1000 cavity fill is:-

  • an eco-friendly, insulating aggregate made from mineralised wood chips.
  • a cavity filling material for all non masonry cavities or masonry cavities above DPC with external insulation.
  • a rapidly installed, load bearing, levelling, insulation fill for solid floors.
  • great acoustic and thermal insulation for suspended floors.

Product overview

Where is it used?

  • Cemwood CW1000 can be used as an insulation fill under wet or dry screed materials, under floating timber floors or under the Lithotherm underfloor heating system.
  • It can also be used within timber floor structures to reduce sound transmission and increase thermal insulation.
  • Suitable for new build or refurbishment projects.

How is it used?

  • Voids should be dry and free of debris and moisture for maximum effectiveness.
  • If used in a masonry cavity wall ensure a barrier is installed at DPC level to prevent Cemwood filling up below DPC. Also ensure air bricks are not blocked.
  • The Cemwood CW 1000 can simply be poured in from the top of the cavity and allowed to fill the cavity below. Tricky areas can be vibrated with a blunt SDS hammer chisel on a solid piece of timber pressed against the wall to ensure complete filling.
  • For floor levelling, the Cemwood CW 1000 comes in sacks and can be simply poured in to place and levelled off with thicknesses varying from 10 – 60mm maximum.
  • The easiest way to instal is to set up rails, using timber battens or metal pipes and level off with a long straight edge.
  • Once levelled, carefully remove rails and fill in voids.
  • Before laying a timber floor over, add a layer of 22mm UdiTOP wood fibre boards to spread the load and prevent any granules getting in to the T&G joints in the flooring.

How much will you need?

Cemwood CW 1000 has a density of 0.32kg per mm per m² (1mm thickness over 1m²). Each 16kg bag (50 litres)  will cover up to 1m² at 50mm thickness or 5m² at 10mm thickness.

Frequently asked questions

How long does it take to set?

  • Cemwood CW 1000 is a dry product and can have a load applied to it immediately after laying. There is no drying required.
  • We can also supply a Silicate solution which can be sprayed over the Cemwood CW 1000 to bind the surface granules together. This will typically cure overnight to form a hard crust on the surface. Please contact us for details.

What are its properties?

  • Thermal conductivity – 0.07 W/mK
  • Grain size – 1-5mm

Technical details

Pricing & shipping

This product will require one pallet space and so shipping is likely to cost between £50 and £100, depending on where you live. Contact Us for a more accurate costing.

Bag weight (kg) Coverage [m²]Single bag costFull pallet bag cost
161m2 @ 50mm£21.75£19.58

Book your free project consultation

We’d like to hear from you. Call us on 01392 861763 or email us at with any questions or comments.

If you can’t seem to find what you need on our website or you have large quantities of materials to purchase please contact us for a chat and we’ll offer you a more bespoke solution.

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