Radiant Heat & Hardwood Floors
Not knowing the proper procedures for installing wood floors over in floor radiant heating systems can spell disaster for any new floor. Radiant heat under hardwood is done through installation of tubing in concrete or below plywood subfloors.
It's important to note any radiant heating system should be turned on prior to any installation... over a period of 5-6 days or longer to insure there will not be any complications. New concrete slabs may require longer periods of time. Reasons for activating the heating system before any installation are to dry out any excessive moisture in the subfloor itself. Skipping this important step will allow moisture in the subfloor to enter the flooring itself resulting in numerous undesired effects.
Go Slow With Start Up
When using the radiant heating system at the onset of winter or cooler months, it is strongly suggested to turn up the heat gradually. Not doing so will cause the floors to cup or crown or show other undesired characteristics. As in mother nature...don't shock the environment...do so gradually over a period of time.
Some hardwood species are not suggested for radiant heat floors. Quarter sawn or rift sawn hardwood is preferred over plain sawn material due to its dimensional stability. In addition, strip flooring(2 1/4" in width) would be a better choice because narrow boards expand and contract less than that of wider boards. Furthermore, strip floors have more seams to receive the seasonal movement and will be less noticeable.
Prefinished Hardwood & Radiant Heat
Just because Joe the builder down the street has installed some radiant in floor heat and plans to use hardwood flooring, don't be led to think it's as simple as that. The majority of prefinished floor manufacturers are reluctant to warrant their products over radiant heat because they have no control over how the system is operated or what type is being used. This not only includes solid hardwoods but engineered as well. The installation preference with radiant heat and manufacturers seems to be with floating floor systems. Reasons being the floor itself is not in direct contact with the sub floor. If in doubt always refer to the specifications from the manufacturer.