Our Vertical Grain Guarantee

by Neil Peterson

Our Vertical Grain Guarantee

One of the features of our sauna building process that we pride ourselves on – which distinguishes us from all mass production products – is our Vertical Grain Guarantee.

We will NEVER use flat grain in any area of your sauna that you are likely to come in contact with while you are bathing in our saunas. We are able to do this because we hand pick each individual board for your sauna to identify color and grain characteristics, and also take great care in deciding which area of your sauna each board should be used. We stress this point, because mass producers aren’t doing anything beyond giving you the appropriate amount of board feet to cover your space.

Why Vertical grain is important:

Vertical grain - radial cut, and Flat grain - tangential cut

Image A

Image A shows the cuts that produce both Vertical Grain (Radial cut) and Flat Grain (Tangential cut) boards. Notice how the Radial cut is a uniform cross-section of vertically aligned, and tightly packed annual rings, while the tangential cut is composed of only a few flat ring-layers. Knowing this, we then consider that wood will shrink and swell to some degree when exposed to heat and moisture, and we can begin to see how the uniform grain pattern of radial cut (vertical grain) boards allows them to resist warping and moisture absorption.

Vertical grain diagram

Image B

Meanwhile, Image B (from the US Forest Products Laboratory) shows how the varied grain pattern of tangential cut (flat grain) boards makes them susceptible to cupping, splintering, and moisture absorption when exposed to the dripping sweat of sauna bathers.

Although the interesting grain patterns of flat grain boards might be pleasing to look at, a sauna with only vertical grain in the “contact areas” is going to hold up much better against years of dripping sweat, and be far less likely to let splinters ruin your sauna bathing experience.

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