by Procraft
Cedar cracks and checks because it is a natural, solid wood that gives up and takes on moisture as the sauna heats and cools. Fine cracks that run along the grain are called checks, and they are normal. They do not weaken the wood and they do not mean anything is wrong with your sauna.
Wood holds moisture, and it shrinks a little as it dries and swells a little as it takes moisture back on. A sauna puts wood through that cycle every time you use it, hot and a bit humid, then cool and dry again. The surface of a board dries and moves slightly faster than its core, and that difference shows up as thin cracks along the grain. Those surface cracks are checks.
Checking happens along the grain, on the surface, and it does not run through the board or break it. It is a feature of building from real solid wood rather than a man-made board. On cedar it is expected, and it does not affect strength, safety, or how the sauna performs. Many owners come to like the character it gives the wood over time.
You cannot stop wood from moving, but a few habits keep it gentle.
Normal checks are thin, shallow, and run with the grain. If you ever see something different, a board split clean through, a joint pulling apart, or a bench that has gone loose, that is a construction matter rather than normal checking, and it is worth having a look at. Everyday surface checking is simply cedar being cedar.
Procraft builds Western red cedar saunas and makes four CSA-approved electric sauna heaters, from 4.5kW to 9kW. See the heaters, read about Western red cedar, or learn how our installations work.