Swell Sport · Practical guide

Timber movement in a sauna: recording gaps without guessing the cause

When a gap appears, the most useful first step is a repeatable record. Photograph where it is, describe what has changed and note whether the door, bench or weather protection behaves differently. A sequence of comparable observations is more informative than a close-up labelled “timber problem”.

Swell Cedar Cube 2 in a home setting.

Record change without declaring the cause

The Cube 2 manual identifies grain movement and small changes in stave or panel fit among natural timber characteristics. It also describes weather exposure and seasonal humidity as influences on colour and surface texture. This gives context for keeping a log; it does not decide what a particular gap means. ^[1]

Give every observation a location code, such as rear-left panel joint or door-frame upper corner. Use the same names each time. Avoid marking a finished surface with permanent ink; label the photographs or use a sketch instead.

Build a repeatable observation set

Take a whole-cabin photograph showing the face concerned, a mid-range image showing the joint and a close view with a ruler held beside it. Keep the camera square to the surface where practical. Record the visible gap at a recognisable point rather than choosing whichever part looks widest in each photograph.

Your log can have these fields: date; location; cabin cool or recently used; recent rain; visible width; photo filenames; door behaviour; water observed; action taken. Leave an entry blank when you could not observe it safely. A blank is better than an estimated measurement presented as exact.

Keep the baseline useful

Take your first set when the cabin is cool and accessible. Repeat from the same positions when you next inspect, noting different conditions rather than attempting to recreate them with heating or wetting. Add an extra entry after a noticeable change or a weather event.

Do not insert tools into a joint to discover its depth or tighten a band to see whether the gap disappears. The Cube 2 band instructions warn against overtightening and crushing or marking timber. Recording should leave the assembly as found. ^[1]

Example: the same joint on two visits

Suppose an owner notices a line at the rear panel after rain. The first entry says “rear-left joint; rain overnight; cabin unused; no interior water seen”, with the three photographs attached. At the next cool inspection, the owner repeats the photographs and records whether the line looks the same.

If the door also starts rubbing, make that a separate observation with its own date. The Cube 2 troubleshooting table lists base level and timber movement as possible causes of door rubbing. Passing on both observations helps support decide what to inspect rather than treating the line alone as the answer. ^[1]

Send a question that can be answered

Ask: “Does this joint need inspection, and may the cabin remain in use while you assess it?” Include the installation date, model and any earlier adjustments. If a bench, glass fitting or supporting part is loose or damaged, pause use and request assessment instead of extending a seasonal log. The log supports a decision; it is not a substitute for one.