Avoiding Problems When Mixing Hardwood Floors
When installing wood floors, homeowners and contractors need to measure the moisture content (MC) of the flooring before installation. Sounds simple enough.
However, more and more flooring products combine multiple wood types. Engineered wood flooring uses the selected species for the top layer (the lamella), while the layers beneath can be other species or wood composites, such as plywood or medium- or high-density fiberboard.
Mixing wood species and grains can create beautiful patterns, colors, and textures. But whether you’re manufacturing or installing these products, keep this in mind: each type of wood has its own MC.
Moisture Content Basics
Wood is hygroscopic: it absorbs moisture from the air when the relative humidity (RH) rises, and it swells as it does. When the RH falls, wood releases moisture back into the air and shrinks.
Lumber producers kiln dry wood to a target MC based on the end product’s service conditions before shipping it to market. Ideally, that target is close to the wood’s equilibrium moisture content (EMC) in service. EMC is the point where the wood neither gains nor loses moisture because it’s in balance with the temperature and RH of the air around it.
Moisture levels keep changing as the wood responds to its surroundings. After a wood floor is installed, homeowners can expect it to expand and shrink to some degree as the RH changes, especially with the seasons and with heating, ventilation, and air-conditioning (HVAC) use.
Builders and homeowners use wood moisture meters to measure and manage the MC of wood over time. Before installing wood floors, contractors use a wood moisture meter to make sure the flooring’s MC has balanced with the building’s conditions, and they keep checking that the MC stays within the manufacturer’s specifications during installation.
After installation, a moisture meter can also help track how the flooring’s MC changes with the seasons or the weather.
The Mixed Wood Conundrum
The industry is using more mixed wood products, and the durability and beauty they offer come with a caution. Some wood panels and wood flooring products contain more than one type of wood, and each has its own MC.
Oriented strand board (OSB) was developed in the late 1970s as an outgrowth of waferboard. It’s an engineered wood panel made from thin wood strands, cut mostly from small-diameter logs, and bonded with exterior-type resins under heat and pressure. OSB panels are built from layered mats: the strands in the surface layers are aligned in the long panel direction, while the inner layers are random or cross-aligned. The mats are pressed into large master panels, which are then cut to size. The result is a structural wood panel built for performance.
Wood flooring installers may install engineered wood flooring over a subfloor containing OSB. Engineered wood flooring typically bonds the selected species on top to less expensive layers underneath for support and stability. The manufacturing process usually makes these products fairly stable, but when MC isn’t monitored, problems multiply with every different species or material in the finished product.
Consider this: a floor made from one species shrinks and swells at one rate, but a floor made from several species can shrink and swell differently, based on each species’ shrinkage values. Engineered flooring made with different species and wood composites makes MC measurement even trickier.
Free Download – Wood Flooring Installation: What To Expect
Mixed Wood Moisture Measurement
Wagner Meters makes wood moisture meters for a wide range of situations. The Orion® 930 Dual Depth Moisture Meter measures MC at two depths, 1/4 inch or 3/4 inch, so it works for many wood thicknesses. The Orion 950 adds a built-in temperature and humidity sensor to monitor the conditions around the wood you’re measuring.
All Orion meters include an On-Demand Calibrator and species settings, so you can accurately measure the MC of each species you work with. When installing new wood floors or restoring old ones, you can check the wood’s MC before sanding and finishing.
The Orion 930 and 950 also have a relative mode for checking moisture in non-wood building materials such as drywall, plywood, OSB, and MDF, which makes them useful for building inspectors, too.
Because they’re pinless, Orion meters don’t leave pinholes in the wood. With so many complex wood flooring products on the market, an accurate moisture meter is a smart investment.
Troy Edwards is Technical Service Supervisor for Wagner Meters, Inc., where he oversees manufacturing, quality control and IT service for their electronic measurement products for the building and construction industry. Troy holds an AAS in Electronics Technology and has over 20 years’ experience in various electronic manufacturing and production positions.
Last updated on October 12th, 2026
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