29 Sep Installing the Natural Floor, Part 1
Air conditioning gets installed in the nick of time for proper moisture levels needed for hardwood and cork
In preparing to install hardwood flooring, we have been monitoring moisture levels at this new construction site for weeks. It’s part of our normal preparation for installing hardwood and cork floors.
“Don’t leave the windows open overnight or we’ll be sabotaged by night-time condensation,” our quality-control manager says. “The air conditioning is being installed tomorrow, and as long as that happens, we should be fine.”
Tomorrow will be just 24 hours before all the flooring is delivered to acclimate in the home for three days prior to installation. The moisture content in the subfloors has been measured and was fine, but the relative humidity has been climbing since the walls were painted.
The standard moisture content of hardwood flooring delivered in this region of the United States is 6 to 9 percent. And this should be the case at the time of installation. The relative humidity in the building should be within 40 to 60 percent, though our goal on this project was to keep it at 45 to 50 percent.
The subfloor, in this case wood, should not deviate more than three percent from the moisture content of the flooring going over it. Relative humidity can be measured with a hygrometer. Moisture in the flooring and subfloor are measured with moisture meters.
Wood expands and contracts with moisture changes. Too much moisture can cause serious problems when flooring absorbs the moisture, expands, hits the boards next to it, and the sides curve upward. Another issue with expansion is that the floor can grow progressively in the direction it is installed.
On September 25, the HVAC in this home was turned on. By the next morning, the relative humidity was under control, averaging 52 percent while the flooring was delivered to the site.
All the levels were measured again Friday morning. All levels were in the desired ranges. The lowest reading was 5 percent, found in one area of the subfloor. The plywood, which will be used to raise the height of the cork, was ranging from 8 to 10 percent.
These ranges were checked again – meeting the standards — when the installation crew showed up this morning.
Let the work begin! ©
— Nancy Kibbee is technical director and editor at naturalinteriors.com