Solid hardwood is manufactured from a single piece of wood, the most common thickness of a solid hardwood plank is ¾". The most widely used profile is tongue-and-groove (T&G). Engineered hardwood consists of 2 or more layers. The top layer is wood veneer (industry norm is 2-4mm think top layer. The lower layers consist either of several layers of plywood, HDF or solid wood). Multiple layers are bonded together under pressure. Plank profiles may be either tongue-and-groove, or use a click-locking technology.
Solid hardwood is a 100% natural product that responds to air humidity variations. During warm and humid summers, it is not unusual for wood to expand. During cold and dry winters, wood can contract. If room temperature and humidity levels are not kept in the optimum range, minor gapping or cupping may occur seasonally. Because of the cross-layers of plywood and/or real wood used for middle and bottom layers, engineered hardwood flooring has enhanced internal balance and reduced possibility of twisting or warping. Seasonal movement is minimal, while dimensional stability through seasonal humidity and temperature fluctuations is superb. This is why engineered hardwood flooring is preferable over solid in interiors where fluctuations in humidity and temperature may be significant (cottages, basements etc.).
Price & Installation:
Some may assume that engineered hardwood is naturally cheaper than solid hardwood, but this is not always the case. Plank size, cost of lumber, as well as cost and quality of glues (used for adhering layers of engineered flooring) are often the cost determining factors here. Additionally, the cost of installation varies. Solid hardwood should be installed on or above grade, using nail down or staple down installation method. Engineered hardwood can be installed in a wide range of interiors, on, below or above grade. Depending on construction type, nail down, glue down or floating methods of installation may be used which significantly reduces installation costs.
Solid hardwood floors are a natural and eco-friendly flooring choice. In engineered hardwood flooring, glues and materials used for middle and bottom layers define whether the floor is non-toxic and eco-friendly. Engineered floors, in which middle and bottom layers are made of solid wood, and are bonded by high quality non-toxic glues, are equal in their eco-friendly characteristics to solid hardwood.
Because the look and feel of solid vs engineered hardwood is virtually the same, the decision on which one to purchase and install should not be a matter of personal preference, but rather a question of cost, climactic factors and other practical considerations.