THERMOASPENMaterial reference
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Thermory thermo-aspen wall cladding

Thermo-aspen
wall profiles

STS4, STEP, KYTE, and VIRE are all Thermory thermo-aspen at its Medium modification level. They differ in face and covering width, and STEP is also thicker. Thermory catalog, pp. 8, 9, 10 The face sets the look of the wall. The covering width sets how many linear feet you order.

Sizes and coverage at a glance

Covering width is the face a board shows once it is installed. The tongue and groove hide the rest. Divide 12 by the covering width to get linear feet per square foot of wall.

For the same wall, STEP needs about 43% more linear feet than STS4 1×4. STS4 1×5 needs about 27% fewer. Then add 5 to 10% for cutting loss. Thermory USA guide, p. 2 How much thermo-aspen do I need? works a whole room, with the door and ceiling.

Thermory thermo-aspen wall profiles, in inches

ProfileActual sizeCovering widthLinear ft per sq ftFace
STS4 1×40.59 × 3.54 in3.15 in3.81Flat, with a slim groove at each joint
STS4 1×50.59 × 4.72 in4.33 in2.77Flat, with a slim groove at each joint, on a wider board
STEP 5/4×31.06 × 2.52 in2.20 in5.44Stepped, with a deep square shadow at each joint
KYTE 1×40.59 × 3.43 in3.15 in3.81Raised ribs with narrow grooves between them
VIRE 1×40.59 × 3.50 in3.11 in3.86Sawtooth, with angled facets
Sizes and covering widths come from the Thermory Sauna Materials catalog, June 2026, converted to inches. Linear feet per square foot is 12 ÷ the catalog’s unrounded covering width, before cutting loss. Thermory catalog, pp. 8, 9, 10
Texture view of the STS4 1x4 face: flat, with a slim groove at each joint
Flat face

STS4 1×4

A flat face with a slim groove at each joint. It is the narrower of the two STS4 sizes on this page.

In short A flat face that shows the grain, not a machined pattern.

Actual size0.59 × 3.54 inCovering width3.15 inLinear ft per sq ft3.81SKU familyTH-ASP-1X4-STS4

Sizes converted to inches from Thermory’s catalog. Thermory catalog, p. 8 Price, lengths, and availability are on the live listing.

Open in SaunaDesignPro See current price and lengths
Sauna lined with horizontal Thermory STS4 thermo-aspen boards on the walls and a curved ceiling, with lit benches
Horizontal STS4 thermo-aspen on the walls and the curved ceiling.Photo: Elvo Jakobson for Thermory
Texture view of the STS4 1x5 face: flat, with a slim groove at each joint, on a wider board
Flat face, wider board

STS4 1×5

The same flat STS4 face on a wider board, so a wall shows about 27% fewer joints than with the 1×4.

In short Wider cover, so fewer rows to fasten.

Actual size0.59 × 4.72 inCovering width4.33 inLinear ft per sq ft2.77SKU familyTH-ASP-1X5-STS4

Sizes converted to inches from Thermory’s catalog. Thermory catalog, p. 8 Price, lengths, and availability are on the live listing.

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Texture view of the STEP 5/4x3 face: stepped, with a deep square shadow at each joint
Stepped face

STEP 5/4×3

A thicker board with a stepped face. Each joint forms a square step that casts a shadow line.

In short The thickest of these boards, with the most rows per wall.

Actual size1.06 × 2.52 inCovering width2.20 inLinear ft per sq ft5.44SKU familyTH-ASP-54X3-STEP

Sizes converted to inches from Thermory’s catalog. Thermory catalog, p. 9 Price, lengths, and availability are on the live listing.

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Texture view of the KYTE 1x4 face: raised ribs with narrow grooves between them
Ribbed face

KYTE 1×4

Raised ribs with narrow grooves between them run the length of each board.

In short Same cover as STS4 1×4, so a wall takes the same linear feet.

Actual size0.59 × 3.43 inCovering width3.15 inLinear ft per sq ft3.81SKU familyTH-ASP-1X4-KYTE

Sizes converted to inches from Thermory’s catalog. Thermory catalog, p. 9 Price, lengths, and availability are on the live listing.

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3.43 in wide3.15 in cover0.59 in
KYTE 1×4 end view, simplifiedThe thickness, width, and installed cover are Thermory’s catalog figures, converted to inches. The face pattern is drawn schematically, not to scale. Thermory catalog, p. 9
Texture view of the VIRE 1x4 face: sawtooth, with angled facets
Sawtooth face

VIRE 1×4

Angled facets run the length of each board in a sawtooth pattern.

In short Angled facets at nearly the same cover as STS4 1×4.

Actual size0.59 × 3.50 inCovering width3.11 inLinear ft per sq ft3.86SKU familyTH-ASP-1X4-VIRE

Sizes converted to inches from Thermory’s catalog. Thermory catalog, p. 10 Price, lengths, and availability are on the live listing.

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3.50 in wide3.11 in cover0.59 in
VIRE 1×4 end view, simplifiedThe thickness, width, and installed cover are Thermory’s catalog figures, converted to inches. The face pattern is drawn schematically, not to scale. Thermory catalog, p. 10
Sauna with vertical Thermory VIRE thermo-aspen wall panels, SHP thermo-aspen benches lit from below, and a stone-filled heater
VIRE thermo-aspen wall panels with SHP thermo-aspen benches. This room uses the narrower VIRE size, 0.59 × 2.72 in. Thermory catalog, p. 10Photo: Elvo Jakobson for Thermory

From Thermory USA’s installation guide

Before you order

These points apply to every profile on this page. They come from Thermory USA’s 2026 guide to sauna wall paneling. Thermory USA guide, pp. 2, 3 The framing guide covers battens and the air gap behind the boards.

  • Take off quantities from the covering width, then add 5 to 10% for cutting loss. The loss depends on board length.
  • Order enough for the whole room. Shade can differ slightly between production batches, so open several packages and match boards as you go.
  • Run the battens across the boards: vertical battens for horizontal paneling, horizontal battens for vertical paneling.
  • Panel the ceiling first, then the walls.
  • On horizontal runs, work from the top down with the tongue up and the groove down.
  • Fix each board with staples through the groove side. The guide recommends a staple gun with stainless steel clips and says finishing nails are not suitable.

Plan the room

Try the finalists in 3D

Each profile opens in SaunaDesignPro with the material selected. Set the room size, benches, heater, and openings, then compare faces in the same space.

Choose a profile to design

Benches and touch surfaces

SHP boards finish the benches

SHP is Thermory’s bench board. The 5/4×4 thermo-aspen size measures about 1.10 × 3.54 in. Thermory catalog, p. 16Add bench supports behind the paneling: Thermory USA’s guide says the paneling must not carry the benches’ weight. Thermory USA guide, p. 4

See bench boards