Charred Timber Documents
Technical Documents for Architects and Specifiers
Our charred timber technical documents cover durability science, BREEAM credits, product data and a full H21 NBS specification. Everything below is published as a live page rather than a PDF, so it is always the current version and you can link colleagues straight to it.
These charred timber technical documents are written for architects, specifiers, structural engineers and contractors. Each carries a version number and published date at the foot. You can therefore see at a glance whether you are reading the current issue. If a question is not covered here, get in touch directly and we will answer it properly.
The Charred Timber Technical Documents
Nobody else in this sector publishes evidence-based technical material at this level. That is deliberate on our part. Specifiers should be able to check a claim rather than take it on trust.
NBS Specification – Charred Larch Cladding (H21)
A complete H21 specification covering system performance, timber procurement, board specification, battens, breather membrane, fixings and installation detailing. The clauses can be lifted straight into your own project document. It also sets out our turnkey supply option, where we scope and source every component the system needs.
Technical Data Sheet – Larch Charred Timber Cladding
Board dimensions and profiles, density, delivered moisture content, char depth by finish, expected service life, fixings and maintenance intervals. This is the product data page. It answers what the material is, rather than how to specify it.
BREEAM Support Document
Where charred timber contributes to BREEAM assessments across MAT 01, MAT 03, HEA 02 and WST 01, plus the innovation category. It also covers the commercial case for a higher rating. Capital value premiums, rental yields and green finance are often the more persuasive argument with developers.
Longevity and Carbon Impact
The material science behind the service life figures, covering pyrolysis, the sacrificial carbon barrier and dimensional stability. Importantly, it also sets out honestly what has to be true for those numbers to hold. Char depth, species and maintenance all matter. The carbon lifecycle is covered too, from sequestration through to composting.
Fire Performance and Euroclass Certification
We are currently working with a number of key players to enable production of our charred timber in a Euroclass recognised format. Until that work completes we are not publishing a fire classification document, because we would rather say nothing than state a rating we do not yet hold.
Requirements for external cladding are set out in Approved Document B. They vary with building height and distance from the relevant boundary. Therefore we would always recommend confirming the requirement with your building control officer early. For the current position on a project, call us on 01422 762100.
Clause 260 of the NBS specification, which covers fire retardant treatment, is marked as under development for the same reason. We will issue certified wording as soon as testing completes and will update this page at that point.
Documents in Development
If there is something you need that is not listed here, tell us. Several of these documents exist because a specifier asked for them first.
Two further documents are currently being prepared. An Installation Guide will cover site handling, cutting, fixing patterns and detailing at junctions. A Maintenance Pack is also in progress, covering post-installation care and maintenance intervals by finish. Both will be published here when ready.
Downloadable Versions
PDF copies of the BREEAM and Longevity documents remain available on request. Our other charred timber technical documents are being reissued to reflect the fire certification position above. In the meantime, the pages linked above are the definitive current versions. If you need a PDF for a project file, email or call us and we will send the current issue.
Need Help With These Documents?
Call us and speak to someone who knows the product, not a call centre.
Or order free samples to assess the finishes alongside the data.
Key facts at a glance
- Company: Grain & Fire Timber Ltd, producing at our Yorkshire yard
- Documents available: H21 NBS specification, technical data sheet, BREEAM support, longevity and carbon impact
- In development: Installation guide, maintenance pack, fire classification document
- Char depth: 1-2mm Brandy and coloured, 2-3mm Raven, 3-5mm Dusk
- Service life: 50 years (Raven) to 80 years (Dusk), subject to maintenance
- Certification held: FSC and PEFC Chain of Custody
- Fire classification: Euroclass certification currently in development
- CPD: Structured session available for practices – see our CPD page
- Phone: 01422 762100
- Website: grainandfiretimber.co.uk
Common questions, answered plainly
What technical documents does Grain & Fire Timber provide?
Grain & Fire Timber publishes a full H21 NBS specification, a technical data sheet covering physical and mechanical properties, a BREEAM support document, and a longevity and carbon impact document. Each is published as a live page with a version number and published date, so specifiers can confirm they are reading the current issue.
Is there a fire classification document available?
Not at present. Grain & Fire Timber is working towards production in a Euroclass recognised format and will publish certified documentation once testing completes. Requirements for external cladding are set out in Approved Document B and vary by building height and boundary distance. Contact Grain & Fire Timber on 01422 762100 for the current position on a specific project.
Can I get PDF copies for a project file?
Yes. PDF copies of the BREEAM and longevity documents are available on request. Other documents are being reissued to reflect the current fire certification position, so the published pages are the definitive versions in the meantime. Email or call Grain & Fire Timber and the current issue will be sent.
Does Grain & Fire Timber supply the full cladding system?
Yes. Alongside the boards, Grain & Fire Timber can scope and source breather membranes, battens and counter-battens, ventilation strips, insect mesh and stainless steel fixings, and can arrange installers experienced with charred timber. Full detail is set out on the NBS specification page.
How do I get technical support on a live project?
Call Grain & Fire Timber directly on 01422 762100. The team can review a draft specification before it is issued, advise on finish and char depth for a particular exposure, and provide Chain of Custody documentation for BREEAM assessors.
Document control: Technical Documents index. Version 1.0. Published September 2026. Individual documents carry their own version references on their respective pages.
