Case Study

A thatched-roof strip and re-roof, incorporating SKYTECH PRO XL non-combustible underlay

Batchcott House

A thatched-roof strip and re-roof

Skytech Pro XL provides a multi-purpose solution for a challenging thatching project.

View products used in project


Richards Castle, Shropshire
April 2021


Providing a non-combustible secondary waterproofing underlay, with additional thermal & acoustic benefits.

200m2 Skytech Pro XL

Why Permavent was chosen

Permavent Ltd are specifiers of a unique roofing underlay which is advantageous for thatched roof applications and has revolutionised traditional thatched roofing practices. Skytech PRO XL is a non-combustible A2-s1, d0 membrane, providing improved watertightness (W1) and vapour-permeability in accordance with BS5534 & 5250. Skytech is also an insulant, providing additional thermal and acoustic benefits. For these reasons Permavent Ltd are providing a modern, aesthetically invisible improvement to traditional roofing.

Permavent SKYTECH PRO XL was recommended by the Thatcher for the following essential benefits:

  • A flexible, more water-resistant and cost-effective alternative to rigid fire-boards.
  • A combination of integral and external SKYTECH tapes guarantee excellent fire protection (A2-s1, d0).
  • Robust Watertightness (W1), acting as an important temporary roof covering during the thatching process.
  • Additional thermal & acoustic benefits realised, using high performance insulation within SKYTECH’s technology.
  • A fully breathable solution, compliant with BS5250 Control of Condensation.

A rethinking of the ‘Dorset Model’, Thatchers like Keith Walden can install Skytech PRO XL with ease and confidence, a primary reason for Permavent Ltd’s involvement in Batchcott House. The property is a family home and holiday cottage in rural Shropshire, with roofing elevations dating back to the 16th century.

How Permavent Products were installed:

The existing thatched roof was stripped, exposing areas of original thatch from the 16th century, 1500mm deep. Where necessary rafters have been replaced with new treated timber.

SKYTECH PRO XL has been installed as per Permavent’s fitting instructions, good roofing practice and compliance with BS5534 & 5250. Restrained using treated batten and counter-batten, prior to installation of new Water-Reed thatch.

Accompanying Materials

  • New Timber Frame Rafters
  • Treated Timber Batten & Counter-Batten
  • New Water-Reed Thatched Roof


Merchant: Boden Roofing Supplies

Installer: Keith & Tom Walden: Walden and Sons Master Thatchers

Products used

Skytech PRO XL

A2-s1, d0 non-combustible, insulating breathable membrane

  • Excellent thermal, waterproof, soundproof & airtight properties
  • Super thin: only 13mm
  • Quick and easy to install