There are basically two systems for sealing parquet: lacquer sealing and oiling (oil-wax). A lacquer seal lays a closed, film-forming protective layer over the wood. It is very durable, easy to care for and water-repellent, but must be fully sanded off and reapplied when worn. Oiling penetrates into the wood, emphasises the natural grain and can be touched up in sections, but requires more maintenance and is more sensitive to moisture.
The process almost always begins with sanding: the parquet is sanded flat in several passes with progressively finer grit to remove the old coating, scratches and unevenness. The floor is then vacuumed clean, filled if necessary and – depending on the system – primed. Two to three coats of lacquer or oil are then applied, with intermediate drying and often a light intermediate sanding for a smooth finish.
The full treatment usually takes two to four days for an average room, mainly because of the drying and curing times. Although the floor is walkable after the final coat, the seal only reaches full load capacity (furniture, carpets) after several days up to two weeks.
Sealing makes sense for newly laid, untreated parquet as well as for older floors whose surface is dull, scratched or worn. A well-maintained solid parquet can be sanded and resealed several times – which makes it particularly long-lasting.
For sanding and resealing in Switzerland you can usually reckon on around CHF 40 to 70 per m² including material, depending on condition, wood type and number of coats. Small areas or elaborate preparation cost more (guide values, no guarantee).