It is widely known that wood needs more maintenance compared to fiberglass or polypropylene. That means wooden hot tubs and wooden saunas require more effort to maintain. On the other hand, wooden hot tubs are 100 % natural and traditional.
Swelling of the hot tub
Newly purchased wooden hot tub needs to swell in order to keep water inside. Since wood absorbs water it expands and closes little gaps inside the structure. But please keep in mind that wooden hot tub will always have some level of leakage. It is 100 % normal and natural. On the other hand, fiberglass or polypropylene hot tubs do not have such leaks but they are not completely natural and traditional. Thermally treated wooden hot tubs (thermowood) have smaller permeability due to their water capillaries are closed during the wood preparation (heating in high temperatures).
Normally the swelling of a new hot tub takes about 2-5 days. During the process, one can use sawdust or coffee powder. It should be noted that bathing during these days is not recommended. Sawdust is poured in water, therefore, little particles attach and fill the gaps eliminating the leakage of water faster.
Impregnation helps to fight the negative influence of moisture which always affects the wood. That should be done twice a year (before and after the winter). It must be noted that only outside of a wooden hot tub should be covered with oil. Linseed oil is widely used for such purpose.
Wooden hot tub needs to be moist all the time
Wood should be kept moist all the time in order to avoid shrinkage that eventually results in leakage. If that happens you should proceed as suggested in swelling part again. We would recommend keeping water inside all the time during the warm season but if the hot tubs need a repair or cleaning it should not be kept without water for a long time. One should also know that the tub doesn’t need to be filled with water up to the very top. 10 – 15 cm should always be left in order to avoid overflow.
Wooden hot tubs in winter. How to protect them?
Above recommendations apply only for a warm season. We always recommend to drain water out during the cold season. We strongly advise stopping believing that small electric heaters attached to filtration can help to keep water warm during the winter. By doing so, you are at high risk of damaging the tub. One should be aware that water when frozen takes about 5 % more volume. This could cause the total destruction of wood which could not be repaired for further utilization. It is also widely known that moisture environment in winter is higher than in summer and this helps to keep wood moist even without water. Of course, after winter you should still need to swell the hot tub a bit.
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