From £15.10 + VAT per board

Universal wood fibre insulation board – Beltermo Ultra

Beltermo Ultra Universal wood fibre insulation boards are:-

  • a medium density, dry-process insulation board, suitable for sarking insulation, internal plastering and external rendering.
  • high compressive strength boards, perfect for confident counter-battening.
  • ideal for forming a warm roof which is completely vapour permeable with good thermal mass and acoustic insulation.
  • suitable for external and internal use.

Product overview

Where is it used?

  • On top of your rafters, preventing thermal bridging and keeping noise out, especially for loft conversions.
  • Behind any cladding on walls on timber frames or masonry.
  • As an internal plaster carrier or external render carrier.
  • Beltermo Ultra is suitable for pitched and flat roof constructions.

How is it used?

  • The Beltermo Ultra wood fibre insulation sarking boards should be laid on top of the rafters and fixed in place with counter-battens.
  • For roofing applications the first row should start at eaves level and working in rows, work your way up the roof.
  • To reduce waste the overhang from the first row should be trimmed off and used to start the second row and so on.
  • For use behind cladding the same principles apply.  When working on masonry structures, unless the wall is very flat, timber battens should be fixed to the surface first with SteicoFlex flexible wood fibre insulation between the battens. The Beltermo Ultra can then be fixed to these battens, avoiding any voids behind.
  • Alternatively, apply a levelling plaster to the surface of the wall, texture with a knotched trowel and fix the boards to the surface whilst still wet.
  • Any cut joints or corners can be taped with Ampacoll Fenax tape to ensure weather-tightness.
  • Boards are not suitable for walking directly on unless supported underneath.
  • For installations where the Beltermo Ultra will be left exposed for more than 8 weeks or where metal roofing is to be used, install Ampatop Protecta breathable membrane over, prior to fixing of the counter-battens.
  • To see how to use this product in roofing applications see our guide here – How to install roof insulation
  • To see how to use this product on masonry in rendered walling applications see our guide here – How to install on masonry rendered wall insulation
  • To see how to use this product on timber frame in rendered walling applications see our guide here – How to install on timber frame rendered wall insulation
  • To see how to use this product on timber frame in clad walling applications see our guide here – How to install on timber frame clad wall insulation

How much will you need?

  • The Beltermo Ultra wood fibre insulation sarking boards typically cover an area of 1870 x 570mm (1.07m²) but the exact board sizes vary slightly, depending on their thickness. The 40mm Beltermo Ultra boards are smaller, 1230 x 580mm and cover 0.7134m².
  • Allow 5-10% wastage depending on the complexity of the roof/facade.

Frequently asked questions

What is their thermal conductivity?

The Beltermo Ultra boards have a conductivity of 0.042 W/mK, a density of 180 kg/m³ and a compressive strength of 150kPa (kN/m²)

See it in action

Using the boards over rafters

Using the boards under rafters

Using the boards behind cladding

Pricing & shipping

This product will require two pallet spaces and so shipping is likely to cost between £100 and £200, depending on where you live. Contact Us for a more accurate costing.

Thickness [mm]Weight [kg/sqm]Board dim. [mm], Area [m²]Number of boards per palletPallet covers [sqm]Pallet weight [kg]Pallet dim. [cm] [LxWxH]single board costboard in full pallets
407.21880 x 580, 1.0905661.04450120 x 190 x 135£15.10£13.59
5091880 x 580, 1.0904447.96450120 x 190 x 135£20.08£18.07
6010.81875 x 575, 1.0783840.96460120 x 190 x 135£22.39£20.15
8014.41875 x 575, 1.0782830.18475120 x 190 x 135£29.86£26.87
100181875 x 575, 1.0782221.4410120 x 190 x 135£39.70£35.73
12019.8187.2 x 57.2, 1.0701819.26410120 x 190 x 135£47.63£42.87

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.

We’re normally open from 8.30 am to 5 pm Monday to Thursday, and 8.30 am to 1pm on Friday.