
Description
Description
STS4 cladding dresses the walls and ceiling of a sauna with slim, angular grooves, and takes its name from the 4 mm gap between boards. The result is a symmetrical, strongly defined surface that suits contemporary interiors and combines well with our other cladding profiles. The boards are thermo aspen: heat treated for a tough, rot-resistant structure that releases no resin in sauna heat, with a honey-brown tone and a straight, knot-free grain. Each pack contains six tongue and groove boards, 15 mm thick and 140 mm wide with an effective width of 130 mm, in a choice of 2100 mm or 2400 mm lengths.
Features
Technical Specification
| Dimensions | |
| Thickness × width | 15 mm × 140 mm |
| Effective width | 130 mm |
| Lengths available | 2100 mm or 2400 mm |
| Pack size | 6 boards |
| Product details | |
| Profile | STS4 tongue and groove, slim angular grooves with a 4 mm gap between boards |
| Timber | Thermo aspen (heat treated) |
| Grade | A-grade |
| Manufacturer | Thermory AS |
Timber
Thermo aspen is made by heat treating the softwood, a natural process that lowers the moisture content of the timber and leaves it tough and rot resistant. The boards release no resin in the high temperatures and humid conditions of a sauna. The wood has a honey-brown colouration, a pleasant toasted scent and a straight, knot-free grain. As a natural product, timber shows some colour variation between packs and batches. Lifestyle images are for representation only; the final look of the sauna will vary with the width and placement of the cladding.
Profile
STS4 takes its name from the 4 mm gap between boards. The slim, angular grooves create a symmetrical, strongly defined surface, which has made the profile a popular choice in contemporary saunas. It combines readily with our other cladding profiles to create contrast in the space.
Quality & Wastage
Our thermo aspen sauna timber is A-grade: durable, knot free and with a low risk of splintering. We recommend a 15% wastage allowance for cladding, which also covers the risk of damage in transit. General sauna wood grading standards apply to this timber.
Installation & Care
The boards fit together with a simple tongue and groove system and are well suited to a DIY sauna build. An Installation and Maintenance Guide is available under the Downloadable Files tab. We recommend treating the wood with paraffin oil, which slightly deepens its colour.
Brand
Thermory, founded in Estonia in 1997, is the largest manufacturer of thermally modified wood in the world. Its thermally modified timber is fully natural and chemical free, and its sauna range also includes a wide selection of untreated timber.
Ordering & Delivery
Timber orders are shipped on a palletised service due to their size and may require a kerbside drop. Shipping is calculated at checkout and varies between UK Mainland, Highland and Island postcodes. Lengths up to 2400 mm ship at standard rates. If we do not stock the length you need but a longer board is available, our cutting service can cut it down for a small fee; you purchase the full length and the off-cut is added to the pallet. If you are unsure how much timber your build requires, contact support@finnmarksauna.com.
Delivery & Returns
Delivery
We offer fast and reliable delivery to customers across the UK and beyond. For full details on shipping times and costs, please review our delivery policy.
Returns
We offer hassle-free returns within 30 days of purchase, so you can shop with complete confidence. For details, see our returns policy.
Warranty & Quality Promise
We are committed to delivering products of the highest quality, for details surrounding warranty please contact us.
Description
STS4 cladding dresses the walls and ceiling of a sauna with slim, angular grooves, and takes its name from the 4 mm gap between boards. The result is a symmetrical, strongly defined surface that suits contemporary interiors and combines well with our other cladding profiles. The boards are thermo aspen: heat treated for a tough, rot-resistant structure that releases no resin in sauna heat, with a honey-brown tone and a straight, knot-free grain. Each pack contains six tongue and groove boards, 15 mm thick and 140 mm wide with an effective width of 130 mm, in a choice of 2100 mm or 2400 mm lengths.
Features
| Dimensions | |
| Thickness × width | 15 mm × 140 mm |
| Effective width | 130 mm |
| Lengths available | 2100 mm or 2400 mm |
| Pack size | 6 boards |
| Product details | |
| Profile | STS4 tongue and groove, slim angular grooves with a 4 mm gap between boards |
| Timber | Thermo aspen (heat treated) |
| Grade | A-grade |
| Manufacturer | Thermory AS |
Timber
Thermo aspen is made by heat treating the softwood, a natural process that lowers the moisture content of the timber and leaves it tough and rot resistant. The boards release no resin in the high temperatures and humid conditions of a sauna. The wood has a honey-brown colouration, a pleasant toasted scent and a straight, knot-free grain. As a natural product, timber shows some colour variation between packs and batches. Lifestyle images are for representation only; the final look of the sauna will vary with the width and placement of the cladding.
Profile
STS4 takes its name from the 4 mm gap between boards. The slim, angular grooves create a symmetrical, strongly defined surface, which has made the profile a popular choice in contemporary saunas. It combines readily with our other cladding profiles to create contrast in the space.
Quality & Wastage
Our thermo aspen sauna timber is A-grade: durable, knot free and with a low risk of splintering. We recommend a 15% wastage allowance for cladding, which also covers the risk of damage in transit. General sauna wood grading standards apply to this timber.
Installation & Care
The boards fit together with a simple tongue and groove system and are well suited to a DIY sauna build. An Installation and Maintenance Guide is available under the Downloadable Files tab. We recommend treating the wood with paraffin oil, which slightly deepens its colour.
Brand
Thermory, founded in Estonia in 1997, is the largest manufacturer of thermally modified wood in the world. Its thermally modified timber is fully natural and chemical free, and its sauna range also includes a wide selection of untreated timber.
Ordering & Delivery
Timber orders are shipped on a palletised service due to their size and may require a kerbside drop. Shipping is calculated at checkout and varies between UK Mainland, Highland and Island postcodes. Lengths up to 2400 mm ship at standard rates. If we do not stock the length you need but a longer board is available, our cutting service can cut it down for a small fee; you purchase the full length and the off-cut is added to the pallet. If you are unsure how much timber your build requires, contact support@finnmarksauna.com.
Delivery
We offer fast and reliable delivery to customers across the UK and beyond. For full details on shipping times and costs, please review our delivery policy.
Returns
We offer hassle-free returns within 30 days of purchase, so you can shop with complete confidence. For details, see our returns policy.
Warranty & Quality Promise
We are committed to delivering products of the highest quality, for details surrounding warranty please contact us.





