What is a renovation floor system?
A renovation floor (Dutch: renovatievloer) is a new floor installed in an existing building, usually to replace a suspended timber ground floor over a crawl space whose joists have reached the end of their life. It is almost always an insulated system floor: the old joists and boards are removed and a prefabricated system takes their place. The term comes from the Netherlands, where many older homes have this type of floor.
Dry and wet systems
- Dry system: no concrete is poured and no screed is laid. Beams and insulation blocks are covered with boards such as flooring-grade chipboard or cement-bonded board. Quick, light and walkable straight away.
- Wet system: a reinforced concrete topping is poured over the beams and polystyrene infill blocks, sometimes followed by a screed. Stiffer, but heavier and with drying time.
Many systems use steel or plastic beams with EPS blocks between and below them. There are also cassette systems with steel or composite faces and EPS in between.
Application: what to check
- Drying time for wet systems. Both the concrete topping and any screed must cure and dry before floor finishes go down.
- Weight. A wet system is heavier. In old houses with limited wall or foundation capacity this can rule it out.
- Underfloor heating. Many dry systems are not suitable because the floor is not stiff enough. Always ask the supplier.
- Bearings. Some systems rest the beams on new steel angles fixed along the walls, so you are not dependent on the old joist pockets and the floor ends up level.
- Energy requirements. In the Netherlands a replaced floor must reach a minimum Rc of 2.6 m²·K/W. In the UK, renovating a thermal element brings in Part L of the Building Regulations; check with building control.
Common mistakes
- Blocking the crawl space ventilation afterwards. The void under a new floor still needs to be ventilated.
- Forgetting to plan pipes, drainage and an access hatch in advance.
- Choosing a dry system and later wanting underfloor heating.
Related terms
- Crawl space
- Floor insulation
- Combination floor
- Cassette floor
- EPS
- Beam floor
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