The heat is on at Vastern Timber. After extensive evaluation of the use of the thermal modification process with British hardwoods, validating its environmental credentials, putting technology to the test, and developing a healthy market for native thermally modified hardwood cladding and decking – having the timber processed in France – the company has installed its own state-of-the art Italian modification vessel in a purpose-built unit. The first charge was set to be loaded mid-December, with commercial operation starting January.

With the kit in place at its Wootton Bassett site, managing director Tom Barnes is clearly upbeat about Vastern’s thermally modified business. That’s partly due to the positive prospects he sees for locally sourced timber in an increasingly eco-conscious market. It’s also down to the exhaustive process the company went through before it put equipment on the ground.

“Of course, commercial thermal modification of timber has been around for a while. The Scandinavians introduced ‘Thermowood’ back in the 1980s/90s and modified hardwoods are now available from across Europe and the US,” he said. “I was convinced it was an option to create demand for under-utilised, under-valued British hardwoods, but I’m cautious and wanted to work things out myself to make sure.”

As TTJ reported at the time, Vastern started its investigations into the process around 2015, working initially with Tyler Hardwoods. Going it alone, it then launched its first products under its Brimstone brand, using ash, poplar and sycamore, with the wood trucked to leading hardwood French sawmillers Ducerf for modification. Subsequently these won a TRADA-sponsored TTJ Timber Innovation Award in 2016. With the ultimate aim of doing the modifying itself, backed with a £50,000 R&D grant from the Forestry Commission, Vastern then started looking at the available technology.

“Prices varied widely and manufacturers all made competing claims for their equipment, so we sent wood samples to four plants across Europe using the different makes,” said Mr Barnes. “These batches then went for testing to the EPH laboratory in Dresden. Interestingly the quality was pretty equal and we eventually opted for technology from Maspell of Italy. They’re a long-standing company, who also have a strong heritage making kilns and impregnation vessels, with installations worldwide, so they clearly knew how to make a decent bit of kit.”

The Maspell system works by creating a vacuum and then heating the wood to a core temperature of 210°C.

“With thermal modification the magic starts happening when the wood reaches 160°C, at which, in the presence of oxygen, it would ignite,” said Mr Barnes. “Above this level some of the hemicellulose, onto which moisture locks, is burned away, so the material won’t swell and contract like untreated timber. Starch and sugar is also removed, making it resistant to fungus. We’ve had all three of the species we’ve modified to date, ash, poplar and sycamore extensively tested and they’re all Use Class 1 for above ground use. At the same time, the wood goes a beautiful deep brown, not unlike a walnut. So we’re taking British hardwoods which are unstable, non-durable and undesirable in terms of colour and producing a stable, durable and very desirable product that’s ideal for cladding and decking, which are of course in great demand.”

What Vastern sees adding to its products’ appeal increasingly is the fact that the timber is primarily sourced in a 100-mile radius of its Studley sawmill and Wootton Bassett drying, machining and modifying site.

“Key customers for our modified wood to date have been self-builders and homeowners who are more and more interested in environmental impact and their eyes open up when we tell them it’s from, say, the Longleat estate just 50 miles down the road. They can really relate to that,” said Mr Barnes. “Comparatively, when we say it’s FSC or PEFC-certified the reaction is pretty flat. Architects are also increasingly concerned with footprint and looking for local provenance.”

To validate Brimstone’s environmental credentials, Vastern has also put its modified products through life cycle assessment and, “in a costly and time consuming process”, developed environmental product declarations (EPDs) for them.

“And once we’ve got the modification plant established, we’ll run this again,” said Mr Barnes. “Stripping out the mileage involved trucking the timber to and from France will make a difference.”

Adding to Brimstone’s attractions, he added, is price.

“It was in the ballpark of Canadian cedar, but that’s doubled in price and has been increasingly difficult to source,” he said. “Now we can tell customers its comparable with unsorted Siberian larch. For such a durable, amazing looking timber, why wouldn’t you?”

Vastern would have liked to have set up the plant sooner – it originally targeted the start of 2021, but Covid interrupted. However, in the meantime, its successful relationship with Ducerf has enabled it to continue building a bridgehead in the market.

“We’ve worked very well together and their quality has been impeccable,” said Mr Barnes. “It’s meant we haven’t had to rush the process and demonstrated that the demand is there. It’s shown us that setting up our own plant is a no brainer and no risk whatsoever.

“This last year we sold 600m3 of modified hardwoods and it could have been a lot more, but for the fact that Ducerf’s capacity was limited by strong demand for its own modified products and also post-Brexit customs procedures making it so complicated shipping our timber to and from France. So we’re confident, now we have the process fully under our control, that we can soon fill our vessel’s annual 1,200m3 capacity.”

The new 20mx40m modification unit, 25% of the cost of which was covered by a Rural Development Programme for England grant, is naturally clad in Brimstone and includes a Joulin automated vacuum sticking and desticking machine. Adding to the environmental merits of the set-up, it also features a solar panel array.

“The process is electric and will get most of its power from solar, with the remainder from certified renewable sources,” said Mr Barnes.

Vastern sources its timber from a network of woodland management companies and estates.

“Supply isn’t an issue. We’re well known in the sector and one of the biggest domestic hardwood mills in the country, so can take larger quantities than most,” said Mr Barnes. “Currently there are particularly large volumes of ash available due to dieback felling. We’re persuading woodland managers to separate out the better quality material for us rather than send it for biomass.”

Availability of ash will eventually decline, but Vastern plans to start modifying other species, such as sweet chestnut and Douglas fir. And, having previously undertaken some trials with manufacturer George Barnsdale, it also intends to explore use of modified hardwoods for exterior joinery.

“We want to play around with modification times and temperatures to develop products for interior use too,” said Mr Barnes. “For that market looking for a deep, rich brown wood we see it as an alternative to walnut and stained timbers, which don’t have the same natural appearance. In fact, we’ve already supplied some restaurant and hotel fit outs.”

Taking a wider perspective, he sees strong prospects for thermo modification globally.

“We need to make more of the global forest resource, and thermo modification is the ideal way to increase the durability, yield and value of under-utilised timbers around the world, especially for local markets,” he said.

As for the outlook for Brimstone, he pointed out that Vastern’s new unit has been built with space for a second modification vessel.