Can real solid timber floors be laid with Under Floor Heating?
There is an easy and very quick answer. YES.
But the question has to be addressed, as most suppliers of ‘‘ along with most architects seem to argue that only the engineered product can be used. Tranquility House has been a research project/ house from its inception and here the conventional was never adopted unless it could be shown that it was in fact correct and even then it was usually tested. Not only is every floor in the house different, but each on the ground floor has a different specification of underfloor heating laid under it, and the top two floors are underfloor heated with a different specification again.
After installation, and partly to test the combination, the underfloor heating was run at above 65° for a few weeks – a situation no floor should be subjected to. The larch floor shown here is the office floor in Tranquility and it was subjected to nearly 70° – with (as can be seen) no ill effects.
Similarly with the Horse Chestnut which is the Living Room floor. It is therefore difficult to understand on what basis the advice not to lay solid flooring with underfloor heating under it is given. Perhaps anybody offering that advice should be asked if they have personally seen a problem or are they passing on third hand information.
As a matter of fact the underfloor heating here is never used except for testing and demonstration as in fact it is extremely inefficient, but the tests are fully valid. For the arguments for and against underfloor heating please see What about Underfloor Heating? (coming soon)
Timber is a natural product so it does expand and contract with changes in moisture and temperature, but when kiln dried to around 10% it becomes very stable. It would be true that if thicker boarding were laid (say 25mm oak) and if it were not thoroughly dry right through to 10%, then underfloor heating would make it shrink. But that is due to the timber not being properly dried before delivery, or if it were stored in a damp environment after delivery for a sufficient length of time to increase its moisture content ? then it could shrink a little. However we do know the dimensional change due to any given change in moisture level and it is extremely tiny. So our solid real floors can move a very little, but that is what natural products do.
At the end of the day an engineered floor looks like the factory product it is, whereas a Tranquility floor looks and is handmade. Simply natural and the two cannot be mistaken. The one will take small variations in its stride almost looking better with some imperfection as it is then even more obviously a non factory product, while the other must stay perfect or it looks obviously faulted. The one will be looked at and admired while the other will largely be ignored. Tranquility Flooring is considerably more economic; involves no extensive transport; no manufacture as such (it is only milled and machined), and causes the very minimum of carbon to be emitted — see ‘Carbon Comparison‘. (coming soon)
The choice is always yours, but declining solid floors because you have underfloor heating reduces the choice to an expensive manufactured product.