Let’s begin with a few brief definitions. These are generally accepted guidelines and there are always some exceptions to the rules.
What exactly is Engineered Flooring?
Engineered flooring is a man-made “layered” wood product, similar to plywood, which typically utilizes a more attractive or harder material on the outer (or top) layer. Engineered flooring is normally cross-layered to enhance stability. Some companies use pressed wood or MFD cores underneath and some use soft or hardwood as this base layer. It often comes pre-finished with a factory hardened finish which is generally substantially harder and more durable than a site-finished solid hardwood floor.
What is solid flooring?
Solid flooring is milled directly from a tree and typically comes as a 3⁄4” thick solid plank. It comes in a variety of widths and species and is the most common type of hardwood flooring throughout most of the US. Most commonly it is installed raw or unfinished and then custom stained and “site finished” by a contractor. But it is also available in pre-finished.
Understanding climate and its impact on hardwood flooring:
Wood flooring is almost like a living/breathing material installed in your home or business, and as temperatures increase and humidity rises the flooring will react accordingly by swelling. Reciprocally, as temperatures drop and humidity decreases, this same floor will shrink and experience some degree of separation. Hence the common pops and cracking noises we might hear as well as gapping which might occur in the Wintertime on a wood floor.
Expansion characteristics of solid vs engineered flooring:
As a general rule, solid flooring will expand and contract, sometimes even dramatically when exposed to even normal climate changes. (More so in the widths of 5” and beyond) This can occasionally work to your advantage as in the example of a minor appliance leak on a floor. If it’s a one-time occurrence, and isn’t too substantial, the solid floor may actually return to almost its original state, given time and once stabilized.
The negative is that with seasonal changes your floor might expand and contract dramatically creating an unattractive appearance as well as gaps which could collect dust or even cupping which might serve as a catch point for a shoe or sock.
With engineered flooring:
It takes a great deal more extremes in climate to generate that same expansion or contraction you would see in a solid floor. Engineered tends to be far more stable under normal circumstances and will continue to remain stable throughout the lifetime of the floor. However, if exposed to extreme circumstances, it is forced to expand or contract, those very same properties which allow it to be more stable than solid flooring, could work to keep the engineered floor in that new state.
In other words, if there are going to be dramatic shifts in climate, a solid floor might actually be a better choice as long as you’re ok with the seasonal gapping issue. (A great example might be a cabin up in the mountains with no climate control or HVAC, or particularly if a home is left vacant for extended periods with no HVAC or humidity adjustments.)
Solid wood’s popularity and most common use Solid wood flooring is the most known form and has been used successfully, typically nailed or stapled down over a plywood subfloor, in homes across the US since our country was first formed.
So, when does engineered flooring make more sense?
Wider widths even over plywood subfloors, tend to be more stable with engineered wood. Traditionally, even over plywood, solid flooring widths beyond 5” often will tend to eventually “gap out” or separate. Larger widths of solid flooring may show signs of cupping (where the edges curl up a bit) with seasonal changes. Many contractors prefer not to work with these wider widths to avoid warranty concerns. There can be exceptions but this concern is generally accepted.
Why is engineered flooring more stable:
The very nature of plywood (having multiple layers underneath with the grain going in opposing directions) tends to be more stable, (particularly with widths of 5” or more) and especially in climates where there is high potential for either expansion or shrinkage. As the top layer attempts to expand or contract, the opposing layers underneath will have the effect of counterbalancing that expansion, thus keeping the floor more stable.
Advantages of gluing engineered directly to concrete:
The other area where Engineered flooring is often preferred over solid is when gluing over concrete. If a client is looking for wider widths beyond about 3.25” for a glue down application, engineered tends to be far more stable. Essentially, if you want wider widths over concrete we would always advocate towards engineered flooring. In the end you will have a much more stable floor.
When might solid flooring makes more sense?
Solid flooring in narrow widths (5” or less) assuming proper acclimation procedures are used before installation, are very stable in most homes with good HVAC and humidity control. Also, in a home with extreme environmental climate changes like the cabin example above, solid can be a better choice. If you require the flexibility of sanding and refinishing multiple times over the years to change the style, solid is a good option.
Additional points to consider:
- It is always a good idea to have HVAC and some form of humidity control in your home. We recommend ideally 35-55% relative humidity as ideal to keep your wood floor stable.
- Proper acclimation of your floor will help to ensure a lifetime of better stability. Your installing contractor or supplier will be able to determine the proper acclimation times based upon your choice of floor.
- As with most things, there are always exceptions to the above thoughts
In summary and as a quick guideline, with solid, we recommend no wider than 5” flooring over any surface. If you want wider widths you’re better off choosing engineered. Also, if you are installing over concrete, we strongly advocate engineered flooring as well.