My Hardwood Ground seems Wavy
By David Barkstedt NOFMA/NWFA Flooring Inspector
I received a mobile phone contact from a consumer who commissioned me to examine her prefinished solid wood floor. The floor experienced been installed very last winter season and considering that then experienced develop into “wavy” throughout the width of the boards. The consumer 1st seen this issue for the duration of the summer. The wavy visual appearance she was describing was really cupping.
The floor was installed over a wooden subfloor in the living room and hallway for the duration of the prior winter season. The subfloor in the living room and lobby were installed over a crawlspace with no vapor barrier and no air flow. The subfloor in the hallway was installed over an existing basement with a concrete floor. From a discussion with the installer, I learned that he experienced not done any pre-installation humidity testing and experienced not examined the conditions over which the subfloor was installed. The installer also experienced not acclimated the flooring prior to installation (as expected by the flooring company).
I cautiously examined the floor and analyzed for humidity utilizing a probe-sort humidity meter. I utilized a probe-sort humidity meter that steps electrical resistance throughout the opposed sets of pins that are pushed into the wooden parallel with the grain, testing into sub-floor utilizing one one/eight” penetration electrode to assess the leading three/16″ of the wooden to the bottom of the wooden and then into the sub-floor. I utilized the probe humidity meter to just take measurements with the penetration electrode to the center of the plank, then to the bottom, then into the sub-floor. These exams unveiled humidity imbalances in between the wood floor and the subfloor. There was a humidity imbalance of increased than four percent providing result in for issue.
The humidity imbalance authorized the boards to cup or, as the consumer mentioned, develop into wavy. As humidity degrees elevated for the duration of the summer months, humidity from the crawlspace migrated up through the subfloor into the wood floor.
How to Correct the Ground
The 1st item to address was the origin of the sizeable humidity. A vapor barrier was installed in the crawlspace, as properly as ample venting to let for cross air flow. The moment that experienced been completed, the humidity degrees in between the subfloor and wood floor experienced to equalize. In cases this sort of as this, the time needed to let the humidity to develop into well balanced through the wood floor and subfloor could be up to a 12 months or through a complete heating and cooling cycle. Right after the humidity imbalance is stabilized, it might be essential to sand the floor flat and refinish. Occasionally after stabilization has occurred, the wood floor returns to an suitable visual appearance and/or issue.
Regrettably, in this distinct floor, the boards did not flatten to an suitable visual appearance through stabilization of the humidity conditions. There were extra installation fears, and the consumer at the moment is continuing with authorized steps towards both equally the installer and the retailer.
In the Long run
The installer/retailer is liable for checking to see if the occupation-web-site conditions are suitable for a solid wood floor installation. These checks should really be completed lengthy before the installer comes on the occupation web-site to start the installation. In this circumstance, a speedy inspection when the occupation was estimated would have unveiled that the crawlspace was unacceptable, and consequently the occupation web-site was not ready for a wood flooring installation. Latest recommendations for crawlspaces are that they need to be dry (no apparent humidity or standing h2o) and need to be protected 100 percent by a vapor retarder of 6-mil black polyethylene. Crawlspaces also should really have one.five percent of open venting for each one,000 square toes (ninety two.90 square meters) of floor location, and the venting should really be effectively located to foster cross air flow. In addition to these recommendations, installers need to check and stick to local creating codes.
In this circumstance, not checking the crawlspace was the worst problem, but it was far from the only problem. Humidity meters can be an installer’s best good friend. Humidity content material readings should really be completed on unique locations in the course of the subfloor. Ample acclimation of solid wood flooring prior to installation is a need to, and humidity content material readings of the flooring need to be in just four percentage factors of the subfloor humidity content material before installation can start off. Hygrometer and thermometer readings need to display that the occupation web-site is at suitable temperature and relative humidity degrees. In this circumstance, none of these readings were taken. This also usually means that the manufacturer’s instructions were not adopted. Installers might get absent with disregarding these specifications on some jobs, but sooner or later a occupation like this 1 will charge them, just as it truly is about to for the installer on this occupation.