Guide
Why the subfloor decides everything
Almost every flooring complaint we are called out to is not a fault with the flooring. It is a subfloor that was damp, uneven or simply not prepared.
Damp is the first thing to check
Concrete and screed hold moisture for a long time, and older Cornish properties often have solid floors laid straight on the ground with no damp-proof membrane at all. Glue a vinyl floor to a slab that is too wet and the adhesive fails, the floor lifts and there is no putting it right without taking it all up again.
A moisture test takes minutes. Where the reading is high, a liquid damp-proof membrane is applied and left to cure before anything else happens. It adds a day and it is not optional, whatever anyone else has told you.
Flat, not just level
Level means horizontal. Flat means no humps or hollows. A floor can be perfectly level and still be unusable for a glued vinyl if it has a ripple across it, because every dip will show through a 2 mm plank as a shadow in raking light.
Concrete gets a smoothing compound trowelled over it, sometimes twice, to give a flat surface for the adhesive. Timber floors get a plywood overlay screwed down at close centres, which stops the boards moving and gives a clean, flat surface.
- Smoothing compound over concrete and existing screed
- Plywood overlay over floorboards, screwed rather than nailed
- Old adhesive, gripper and staples removed
- Damp-proof membrane where the moisture reading calls for it
Floorboards move, and so does what is on them
Laying a floor straight onto old boards is asking for the joints to open. Boards flex, they cup, and the gaps between them are exactly where a thin plank will crack or a vinyl will telegraph a line. Plywood spreads the load and gives a continuous surface.
In a period property this also has to be done in a way that keeps the void beneath ventilated. Blocking airbricks to fit a floor causes damp problems that show up years later in the joists.
Acclimatisation is not a formality
Wood and, to a lesser extent, laminate need to reach the temperature and humidity of the room before they are laid. Boards brought in from a cold van and fitted the same morning will move once the room warms up, and the result is gaps in winter or a floor that lifts in summer.
We deliver in advance and leave the material in the room. It costs a day and prevents a problem that cannot be fixed afterwards.