How to Install In-floor Radiant Heating System with Hardwood Flooring

Let’s look at DIY heating installations using radiant heat. When looking at radiant heat, the reluctance to install hardwood floors over radiant heat systems was due to the original technology, from more than 40 years ago.

To allow for poor insulation, radiant heat temperatures were higher than normal, causing excessive expansion and contraction in hardwood floors, resulting in damage to hardwoods and the builder’s reputation.

These days, faultless radiant heat installations of fine hardwood flooring are completed over radiant floor heating.

Realistically, installing hardwoods over radiant heating systems is no different from laying a typical hardwood floor.

Although the temperature of radiant floor heating won’t harm the wooden floor, changes in moisture will cause various hardwood floors to warp, buckle or gap.

As the temperature increases, the moisture content decreases, and the moisture leaves, causing the wood to shrink and gaps to appear between the boards. With lower temperatures, moisture returns and the gaps close.

When radiant heat is added to a floor it’s very important to pay close attention to the levels of moisture.

Hardwood floor installers and radiant heating systems contractors should be aware of the special considerations required when using radiant heat with hardwood floors.

When combined with radiant heat, a lot of contractors underestimate the time it takes for the concrete to cure. Often, when the concrete looks dry the flooring is installed. However, concrete needs to dry slowly and can take up to 90 days to properly cure. Knowing the exact moisture content is an essential part of quality control within the floor installation process.

Once the sub-floor, tubing and climate controls have been installed, run your radiant heating systems for at least 3 days to balance the moisture content.

Your radiant heat and hardwood floors need special moisture considerations. Make sure your installer has a moisture meter, which measures the moisture in concrete and wood floor materials, giving the percentage of relative humidity.

Also, make certain the hardwood flooring, storage space and concrete slab are normalized or acclimated to the finished room before the hardwood is installed.

With a hardwood installation, a moisture barrier helps maintain an even balance in the floor. Seasonal gapping is quite normal, but in the fall gradually turn on the heat before the first really cool day arrives. Also, it’s important for the hardwood floorboards in the floor to be laid perpendicular to the tubing, not parallel.

The key to a good hardwood installation when combined with radiant heat is to pay very close attention to the moisture. Low, even temperature distribution is the key to avoiding problems when radiant heat is involved.

Rodney Couples
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