Case studies

Old Grain Store transformed with Brimstone cladding and joinery

The Sylva Foundation aims to help Britain’s trees and woodlands thrive, for people and for nature. The renovation of an old grain store at the Sylva Centre provides a vast new space for their work, supporting woodworking businesses, innovation and skills training.

Vastern Timber supplied cladding and joinery material in return for the opportunity to set up a long term test and display facility for their innovative ‘Brimstone’ range of thermally-modified British timber. 

MD Tom Barnes explained that “Gabriel, Paul and the team at Sylva have for many years been great supporters of the Brimstone project and our aim to promote under- utilised British timber aligns perfectly with Sylva’s goal of ‘helping trees and people grow together’. In fact the Sylva Centre can lay claim to having the very first batch of thermally modified (TM) British hardwood after their original building was clad in TM  British ash and sycamore. We all saw this project as a great opportunity”

The Grain Store is clad on three sides with British larch feather-edge cladding, selected because it is locally grown, naturally durable and – importantly for this project – affordable.

The most prominent elevation is clad in Brimstone, Vastern Timber’s innovative range of thermally modified British hardwoods, which is made of locally-grown poplar, ash and sycamore. 

Brimstone is an award-winning innovation, made of thermally-modified timber that’s grown in Britain. Learn more at

Vastern Timber supplied over 100m2 of Brimstone to the project, split between ash, poplar and sycamore, and each was installed using a different fixing system by Sylva Centre tenant Rodas Irving (more details below).

Tom said “The purpose of this project was to create an accessible long term research and display site in an interesting location where we and our clients can observe the Brimstone products. All wood looks great on day one, but it’s far more relevant to know how the products will bear up over time. How will the wood change colour? Will the cladding boards distort? Will the joinery swell in the winter? These are all questions that we are happy to answer but we would rather show potential customers the products in situ so that they can be confident about their choices.”

In addition to the cladding Vastern Timber worked with George Barnsdale to produce timber-framed windows and doors made of Brimstone ash for this project. This is the first commercial site to house joinery made from Brimstone timber, and the first joinery to result from our association with George Barnsdale. The Brimstone ash was primed and painted using advanced technologies at George Barnsdale, giving the best protection from the elements. 

Tom said “We hope that this will be the first of many projects for which we can partner with George Barnsdale Joinery to produce the highest quality joinery of thermally modified British hardwoods.”

Research and Development.

The first thermally modified British ash and sycamore were installed on this site in 2105. Since then, Brimstone has been rigorously tested both in the lab and on site. 

All three species have achieved Class 1 Durability for out of ground use in lab based testing and mechanical tests have demonstrated a minimum of 50% improvement in dimensional stability.

During 2018 Vastern Timber invested in an Environmental Product Declaration and an in-depth life cycle analysis to establish the full carbon impact of the three Brimstone species.

In 2019  a weathering station  was installed at the yard in Wootton Bassett to gather information about the natural weathering processes of the timber on different elevations.

“This new installation of Brimstone cladding and joinery at the Sylva Wood Centre is the latest step in our quest to test, observe and fully understand the characteristics of this innovative material. Both the cladding and the joinery will be monitored over time and what we learn will contribute to our growing body of knowledge and in turn the advice we offer to architects and specifiers for projects of the future.” said Tom.

Contact the team at Vastern Timber to find out more about Brimstone thermally modified cladding and decking.

More space for woodworking startups and skills training

The Sylva Centre is home to an inspiring community of woodworking professionals. It hosts start-up businesses in a number of ‘incubation’ units, with links to Oxford City College.

The renovation of the old Grain Store increases capacity, providing more space for woodworking businesses, and for skills training to be delivered at the centre. The Grain Store hosts the MicroFactory “for designers, makers and prototypers and new or small creative businesses that want to work in a rural setting but with a city buzz.”

Timelapse of construction

This short film, taken over several months, shows the process of transformation of the old grain store. After the building was stripped back to the steel frame, the timelapse shows the processes of applying the insulation, then the timber cladding and finally fitting the windows and doors. 

Image gallery

Thanks to the Sylva Centre for sharing images of the construction process.

The cladding installation in detail

The Brimstone cladding was supplied in three versions – ash, poplar and sycamore. All were installed vertically to offer variation to the original modified British timber at the Sylva Centre, which was installed horizontally. 

While it was important that the main elevation looked attractive and consistent, we wanted to include the three different Brimstone species and three different fixing systems to maximise the opportunity to learn from the project. To achieve both aims we kept the board width the same throughout but varied the profiles.

We asked the installer, Rodas, to comment on the ease or otherwise of the various systems. Here’s his reply:

"Fitting the battens accurately paid dividends later on in the process – particularly for the Sycamore which had the hand nailed fixing as we were able to use the horizontal battens as an accurate guide for the position of the nails.

The quality of all the timber was very good indeed. I think we only had one piece that had to be put to one side out of the whole lot of around 500 pieces. There were very few pieces that had any defects – the odd piece with a minor split. Most pieces were straight, a few had some spring but this was easily corrected as we nailed in place. 

The Ash tongue and groove was perhaps the trickiest to put up, just because you have to fit one piece into the other. It could split when nailed if the grain was angled or we nailed a bit close to the edge. 

The Sycamore has the most interesting grain pattern and looks really beautiful. For each board we drilled a pilot hole 3mm using a jig. We then nailed with a 50mm annular ring nail.This was quite time consuming but made easier by having accurate battens to work from.

The Poplar was the easiest to fit. We purposely did this fairly rapidly with a second fix nail gun into both the lap and the face of the boards just lining things up by eye. We didn’t always get this spot on but in reality this isn’t at all noticeable. The poplar didn’t split at all from memory. 

Everyone who came past commented on how good it looked."

It takes teamwork to apply the finishing touches.

For more information about the renovation visit the Sylva Centre website.

Find out more about George Barnsdale, manufacturer of timber windows and doors:

Learn more about Brimstone

Find out more about Brimstone, the British grown, thermally-modified cladding and decking from Vastern Timber at

Read more about the Brimstone Environmental Product Declaration. 

Visit Vastern Timber’s resource centre for technical information about the cladding, the Brimstone EPD, and links to BIM and NBS listings for Brimstone cladding and decking.

Contact the team at Vastern to get a quote or learn more.



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