The main difference between the three woods for sauna manufacturers really comes down to only few characteristics that narrow our choices for infrared sauna construction, crushing strength, shrinkage, average dried weight, working properties & toxicity.
Wood Toxicity is the most important to us because it is the most important to our clients. Most of our clients are looking to detox their bodies from environmental toxins not introduce them. As such toxicity is of great concern as our saunas are used in medical facilities around the country. As such, all of our saunas are specially kiln dried to burn away oils and resins that may otherwise outgas allergens and toxins during the heating and cooling of the wood in the sauna environment.
Wood weight is a concern as it can increase the price of the sauna being delivered to you and limiting the availability to those who need it most. The weight of the wood contributes to difficulty in assembly because heavier wood would need additional hardware to support the added weight increasing the price of the sauna.
Shrinkage is important to note because it tells us how the wood will age over time it will determine how likely the wood will splinter or cracks as your sauna heats up and cools down over time.
Crushing Strength is important because in a sauna environment we don’t want to step through our floor or split our bench as both pose a danger to the end user. Although construction design is also important factor in the strength and durability of your sauna it is important that the wood itself is strong enough not crack or give when under pressure.
The working properties of a wood is of concern because we need a wood that is easy to work with to maintain an affordable price.
As we narrow down the woods based on important properties specific to sauna use we find that Hemlock is the ideal choice for both its hypoallergenic properties, appropriate balance of weight and strength and minimal shrinkage. Hemlock is normally considered to be a scentless, resin-free wood that is available in very large, knot-free dimensions. The wood has a very regular, uniform structure, and is not durable outdoors. Hemlock is not easy to impregnate so surface scarring and imprinting is rare in hemlock. Some infrared sauna companies choose different woods such as Basswood or Aspen but these woods are very soft often poorly hold nails and are more suitable to carving not for a long lasting sauna cabin construction.
So if Hemlock is the ideal wood, why would companies manufacture saunas from Cedar?
In truth most of us are phasing out the use of Cedar. We use it now out of tradition. Most people are unfamiliar with an infrared saunas and immediately associate the sauna with a traditional hot rock or steam sauna. When I say “sauna”, they say “Cedar”. What is important to know about Cedar is that a properly construction Cedar sauna will not have that cedar smell we associate with a cedar chest or closet. In a properly constructed cedar sauna the wood is kiln dried specifically to burn away resins and oils that can outgas during a sauna session eliminating that cedar fragrance. The only benefit of cedar in an indoor sauna is asthetic value. Cedar is a beautiful traditional wood that makes gorgeous furniture but can be susceptible to scarring or indentation due to its soft nature. Cedar also has benefits when used outdoors as it is very durable in regard to decay resistance, and has some resistance to insect attack. All Celebration Saunas are for use indoors only.
If you are seeking and outdoor sauna it is important to choose a Cedar sauna with a pitched roof. It’s important to note that in climates where temperatures drop below 50 degrees it will be difficult to heat any infrared sauna to the ideal temperature for effective use when stored outdoors.
Please use the table below for a comparison of wood properties commonly used in Infrared Sauna Construction.
|Common Name(s):||Eastern Hemlock, Canadian Hemlock||Basswood, American Basswood, Lime, Linden||Western Redcedar, Western Red Cedar|
|Scientific Name: Tsuga canadensis||Tsuga canadensis||Tilia americana||Thuja plicata|
|Distribution:||Eastern North America||Eastern North America||Distribution: Pacific Northwest United States/Canada|
|Tree Size:||65-100 ft (30 m) tall, 2-3 ft (.6-1 m) trunk diameter||65-120 ft (20-37 m) tall, 3-5 ft (1-1.5 m) trunk diameter||165-200 ft (50-60 m) tall, 7-13 ft (2-4 m) trunk diameter|
|Average Dried Weight:||28 lbs/ft3 (450 kg/m3)||26 lbs/ft3 (415 kg/m3)||23 lbs/ft3 (370 kg/m3)|
|Specific Gravity (Basic, 12% MC):||.36, .45||.32, .42||.31, .37|
|Janka Hardness:||500 lbf (2,220 N)||410 lbf (1,824 N)||350 lbf (1,560 N)|
|Modulus of Rupture:||8,900 lbf/in2 (61.4 MPa)||8,700 lbf/in2 (60.0 MPa)||7,500 lbf/in2 (51.7 MPa)|
|Elastic Modulus:||1,200,000 lbf/in2 (8.28 GPa)||1,460,000 lbf/in2 (10.07 GPa)||1,110,000 lbf/in2 (7.66 GPa)|
|Crushing Strength:||5,410 lbf/in2 (37.3 MPa)||4,730 lbf/in2 (32.6 MPa)||4,560 lbf/in2 (31.4 MPa)|
|Shrinkage: Radial:||3.0%, Tangential: 6.8%, Volumetric: 9.7%, T/R Ratio: 2.3||Radial: 6.6%, Tangential: 9.3%, Volumetric: 15.8%, T/R Ratio: 1.4||Radial: 2.4%, Tangential: 5.0%, Volumetric: 6.8%, T/R Ratio: 2.1|
|Color/Appearance:||Heartwood is light reddish brown. Sapwood may be slightly lighter in color but usually isn’t distinguished from the heartwood. The conspicuous growth rings can exhibit interesting grain patterns on flatsawnsurfaces.||Pale white to light brown color, with sapwood and heartwood sections not clearly defined. Growth rings tend to be subtle, and color is mostly uniform throughout the face grain of the wood. Knots and other defects are uncommon.||Heartwood reddish to pinkish brown, often with random streaks and bands of darker red/brown areas. Narrow sapwood is pale yellowish white, and isn’t always sharply demarcated from the heartwood.|
|Rot Resistance:||Resin canals absent; earlywood to latewood transition ranges from moderately abrupt to gradual, color contrast fairly high; tracheid diameter medium-large. Rated as non-durable regarding decay resistance, and also susceptible to insect attack.||Basswood is rated as being non-durable in regard to heartwood decay.||Rot Resistance: Western Redcedar has been rated as durable to very durable in regard to decay resistance, though it has a mixed resistance to insect attack.|
|Workability:||Working properties are intermediate. The wood tends to splinter easily when being worked, and tends to plane poorly. Also, because of the disparity between the soft earlywood and the hard latewood, sanding can create dips and uneven surfaces. Glues, stains, and finishes well.||Easy to work, being very soft and light. Perhaps one of the most suitable wood species for hand carving. Basswood also glues and finishes well, but has poor steam bending and nail holding characteristics. And though the wood is both lightweight and soft, it has an outstanding MOE-to-weight ratio. However, its MOR is on par with its low weight; simply put, when put under stress, the wood will remain stiff, but will still break (rupture) at a relatively average weight.||Easy to work with both hand or machine tools, though it dents and scratches very easily due to its softness, and can sand unevenly due to the difference in density between the earlywood and latewood zones. Glues and finishes well. Iron-based fasteners can stain and discolor the wood, especially in the presence of moisture.|
|Odor:||No characteristic odor.||No characteristic odor.||Western Redcedar has a strong, aromatic scent when being worked.|
|Allergies/Toxicity:||Non-Toxic||Non-Toxic||Sensitizer: Although severe reactions are quite uncommon, Western Redcedar has been reported as a sensitizer. Usually most common reactions simply include eye, skin, and respiratory irritation, as well as asthma-like symptoms and nervous system effects.|
|Pricing/Availability:||Eastern Hemlock is one of the two primary commercial species of hemlock harvested in North America—with the other being Western Hemlock (Tsuga heterophylla). Hemlock is used primarily as a construction timber, and is in good supply. Expect prices to be moderate for a domestic softwood.||Widely available as lumber or carving blanks. Prices are in the lower range for a domestic hardwood, though larger carving blocks are more expensive.||Should be moderately inexpensive for construction-grade lumber, though higher grades of clear, straight-grained, quartersawn lumber can be more expensive.|
|Common Uses:||Boxes, pallets, crates, plywood, framing, and other construction purposes.||Carvings, lumber, musical instruments (electric guitar bodies), veneer, plywood, and wood pulp and fiber products. Basswood is an ideal wood for many woodcarvers. Its soft, fine, even texture make it easy to work with, while its pale, inconspicuous color doesn’t detract from the carved patterns of the finished product (which also makes it easier to paint and color).||Shingles, exterior siding and lumber, boatbuilding, boxes, crates, and musical instruments.