From £12.67 + VAT per board

Wood Fibre Insulation Sarking Boards – UdiTOP

UdiTOP wood fibre insulation sarking boards are:-

  • wet process wood fibre board which is brilliant for keeping you warm and dry in winter.
  • high density and so great for summer heat shielding, keeping your home cool.
  • the best way to form a warm roof which is completely vapour permeable.
  • quick to form a weather-tight, bat friendly covering without using membranes/felt.
  • ideal for use in noisy or urban areas where their acoustic insulation really helps.

This is an image of the larger format 22mm, 35mm and 52mm UdiTOP wood fibre boards.

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.
  • Any roofs where bats live. They get tangled in breathable membranes so are are a great alternative.
  • As part of the Lithotherm underfloor heating system.

How is it used?

  • The UdiTOP 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 UdiTOP boards 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 less than 52mm are not suitable for walking directly on unless supported underneath.
  • For installations where the UdiTOP wood fibre boards will be left exposed for more than 8 weeks or where metal roofing is to be used, instal 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

How much will you need?

  • The 22mm UdiTOP wood fibre insulation sarking boards are 2480 x 585mm or 1.45m².
  • The 35mm and 52mm UdiTOP wood fibre boards are 2475 x 575mm or 1.423m².
  • From 60 – 120mm the boards are 1855 x 575mm or 1.067m².
  • Allow 5-10% wastage depending on the complexity of the roof/facade.

Frequently asked questions

What are their thermal conductivity and compressive strengths?

  • The 22, 35 and 52mm UdiTOP boards have a conductivity of 0.048 W/mK, a density of 260 kg/m³ and a compressive strength of 200kPa (kN/m²).
  • The 60, 80, 100 and 120mm UdiTOP boards have a conductivity of 0.046 W/mK, an average density of 240 kg/m³ and a compressive strength of 100kPa (kN/m²).

See it in action

Using the boards over rafters

Using the boards behind cladding

Pricing & shipping

This product will require three pallet spaces and so shipping is likely to cost between £150 and £300, depending on where you live. Contact Us for a more accurate costing.

Thickness [mm]Weight [kg/sqm]Board dim. [cm], Area [m²]Number of boards per palletPallet covers [sqm]Pallet weight [kg]Pallet dim. [cm] [LxWxH]single board costboard in full pallets
225.7248 x 58.5, 1.45104150.8875250 x 120 x 125£14.08£12.67
359.1247.5 x 57.5, 1.426693.92875250 x 120 x 125£20.12£18.11
5213.52247.5 x 57.5, 1.424462.61870250 x 120 x 125£31.18£28.06
6014.4185.5 x 57.5, 1.0673638.41575190 x 120 x 125£26.90£24.21
8019.2185.5 x 57.5, 1.0672829.88595190 x 120 x 125£33.33£30.00
10024185.5 x 57.5, 1.0672223.47590190 x 120 x 125£44.78£40.30
12028.8185.5 x 57.5, 1.0671819.21580190 x 120 x 125£45.31£45.31

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.