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Flexible recycled cellulose insulation batt suitable for all types of construction

laying Karphosit clay blocks

HOMATHERM flexCL 040 is a very practical insulation material in flexible batt form, made from recycled newspaper and recycled jute sacking. The material is treated with borax to resist insects and to make the insulation fire-resistant. The material is very comfortable to work with, and can be readily cut to fit where necessary. Installation is safe and easy, protecting the health of both installers and building occupants.

Homatherm improves the climate in the building because of its thermal and vapour diffusion capacity - the ability both to regulate temperature and to absorb moisture and gently give it off again. It protects the structure and keeps it dry, prolonging the lifetime of the building fabric.

Homatherm can be used between rafters, joists and timber studs in breathing constructions. It can also be installed as a partial fill insulation for cavity wall construction with a ventilated air gap.

Composition & Manufacture

  • Contains over 90% re-cycled material
  • No toxins or toxic emissions during manufacture

Installation & Disposal

  • No health risks for workforce or installers
  • Easily cut to shape
  • Flexible in all directions
  • No VOC emissions
  • Helps to avoid the use of treated timber
  • Durable / Low maintenance
  • Reusable / actively recycled


  • Excellent thermal performance in Winter
  • Excellent thermal performance in Summer
  • Excellent low-frequency acoustic performance
  • High vapour permeability
  • Hygroscopic (absorbs & releases moisture)
  • Absorbs harmful VOC’s and toxins
  • Vermin and fungus resistant
  • Electrically neutral
  • Non-radioactive
  • Free from toxins and allergens
  • Dimensionally stable (low thermal movement)

HOMATHERM flexCL 040 batts are high-density semi-rigid insulation slabs made from recycled newsprint and 7 - 10% polyolefin fibres.

The cellulose fibres enable the insulation to absorb up to 17% moisture without losing on thermal performance. And since moisture is absorbed by the insulation, not the timbers, structural timbers without preservative treatment can be used.

The polyolefin fibres enable the slabs to be flexible in all directions (their inclusion also resulting in a significant reduction in the embodied energy of the product).

The density of the batts (typically 60-90 kg/m³) ensures superior acoustic performance relative to mineral wool insulation materials whilst the excellent specific heat capacity of the batts ensures that FlexCL batts not only insulate during the winter, but also prevent summer overheating (2.4 times better than a mineral wool of equivalent density).


• Suitable for floors, walls, and roof constructions
• Suitable for partial fill cavity wall construction


Raw materials Cellulose from newsprint
Binder Polyolefin
Fire protecting agent Borax, Boric Acid
Hydrating agent Aluminium sulphate

Dimensions & Packaging

Batt size 1200 x 625 mm
Batt thickness 50 / 80 / 100 / 140 / 160 mm
Coverage per pack 4.5 / 3.0 / 2.25 / 1.5 / 1.5 m²
Coverage per pallet 63 / 42 / 31.5 / 24 / 21 m²

Technical data

Density, ρ 60 - 90 kg/m³
Thermal conductivity, λ10 0.039 W/ m.K
Thermal conductivity, λR 0.040 W/m.K
Specific heat capacity, c 2000 J/Kg.K
Diffusion resistance, µ 1,2
Tensile strength ≥ 6 kN/m²
Tear strength ≥ 3 kN/m²
Fire rating Class B2


• Certification Z-23.11-1338 (DIBt)

Date publishedTitleFile sizeDocument type
Homatherm flexCL 040
Flexible recycled cellulose insulation batt suitable for all types of construction
167 KB Product sheet
FlexCL 040 - safety data sheet
12 KB Technical data sheet
Cutting of flexCL 040
390 KB Technical data sheet

To order this product, or to request pricing / quotations, please do one of the following:

- call us at 020-7232-1181
- fax us at 020-7023-3789
- email us at
- use our online quotation request form.

Our hours of business are Monday to Friday, 10.00 to 18.00.

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111 Rotherhithe Street, London SE16 4NF   tel  020 7232 1181   fax  020 7023 3789