Engineered wood floors are designed for a better compliance to changes of temperature and moisture levels in the subfloors and the environment. Comprising of a lower which may comprise of 1 or more layers of pine or ply and natural wood top layer which may vary from 3 to 6 mm.
The number of layers would define the overall thickness of the floor, which varies from 14 mm to 22 mm. The top layer however, defines the life span of the floors and the number of times the floors can be restored.
Floor sanding of 3 mm engineered wood floors, if carried out by certain rules may give a second chance of restoration. Restoring engineered floors is more or less taking out the top layer of varnish or wax and its re-application.
Start with 40G sanding paper with either rotary sander, trio sander – both preferable on this type of floor, or the good old belt sander. Sanding with a belt sander needs a good control of machine, so experience is essential.
Being too careful or not careful enough – both may have disadvantage. Making sure the sealant is completely removed by the initial sanding is important, as you won’t see it’s visible consequences (if the floors are to be varnished) until second coat of the new varnish is applied.
Usually, difficult to notice with a naked eye remains of the old varnish will stay inside the wood may become visible after the sealant is re-applied. This will happen because of unevenness of planks which may have been slightly bended or raised towards the edges of the planks. A bit of an extra sanding with a fine grid on a hand held sander may keep the trouble away.
After 40G sanding follow with 80G sanding paper and completed the floors with buffing and resealing.
The 6 mm multilayered engineered flooring will have more sanding. It is recommended to keep track of the number of sanding and type of equipments used for floor restoration in a notebook for reference to the next company or floor men to carry out the works.
The floor sanding company attending the works will be curious about the history of the floor and cautious on their quotes. Most likely the responsibility for the results will lay on your hands and keeping a record of the floor restoration will help you be accurate in your decision.