Let’s first understand the composition of each. Solid wood is just that…a flooring plank made out of a solid piece of wood, tongue and groove created on either side and surface finished (natural/stained) with a suitable protective coat (Polyurethane/Lacquer/Oil). The wood is seasoned to suitable moisture content for increased stability. Coming to engineered flooring, this product is once again made of real wood (contrary to some misconception that it is not real – basically a perception generated by the word ‘engineered’). The basic difference is the plank construction hence the word ‘engineered’.
The surface in engineered floor is the decorative wood (any of the various species like oak, merbau, teak and so on) in varying thicknesses (0.6 to 7mm). Although some purists might call the 0.6 – below 2mm top layer as a wood veneer floor! Nevertheless, the bottom layers could be multiply (multiple layers of plywood) or one or two layers of a soft wood (pine/fir/spruce etc) or HDF (high density fibreboard). These various layers of wood are glued together in a cross grained pattern inorder to reduce expansion and contraction to the least. The resultant floor board has normally the latest click installation system just like the laminate floors.
That was the structural description. Now which is better? That depends on what one is looking for.. A solid wood floor will have more life generally (they have been known to last generations – with right maintenance off course..), will sound and feel better (solid). However they cost more – product as well as installation, they are comparatively more prone to expansion, contraction and warping (just like our wooden windows during monsoon) with changes in moisture, are not recommended for basements and your floor rises by around 28 to 32 mm depending on the floor and subfloor ply thickness. This for all practical purposes rules them for renovations.
Whereas engineered floors (with click installation and thinner top layers upto 4mm) are quick and easy to install, can be easily relocated (click installation system) and are much more stable (they react to moisture much lesser). They can also be sanded and refinished if required just like solids only lesser times. A decent product may well last 10 – 20 yrs or even more in a well maintained house. The downside is that they use glue to manufacture which contains formaldehyde which if not coming from a reputed brand, can be of lower quality (very bad for health). Low quality can also cause delamination (layers coming off). Also, some people feel it is not as sturdy which is more of a misconception.
So where do we land up?
Overall, My vote goes for engineered although we sell both! The main reason is reaction to moisture (due to improperly dried sites, lack of proper moisture detecting equipments with flooring contractors, moisture seepages due to bad plumbing, leakages etc) which can cause more trouble for a solid wood floor. In India, I generally find the leakages frequent, time lines too short (particularly for commercial projects) leading to unfit site conditions. However, If your civil construction work is excellent, you can wait till the concrete floor has dried to the proper moisture content or spend a little more to put an extra moisture protection coating and the humidity levels at the place are normal, then by all means choose a solid. Otherwise, you better stick to the engineered!