Sub Floors and their inherent problems for wood flooring

• Concrete screeds, power floated floors
• Joists
• Ground floor joists with open air below which are found in old houses that have air bricks and probably earth underneath
• Old Floor Boards such as pine
• Chipboard or plywood structure
• Underfloor Heating Screed

Concrete: Concrete screeded floors can vary in condition and levels. If it is flat and smooth with a moisture content of 4% or less then we can glue the boards directly to the floor using the Bona R 850 this is always the best way rather than using an underlay and floating the boards.

If you have your own builder or fitter please make sure they are experienced in fitting floors and the consequences of not following the correct procedures for concrete screeds.

Joists: If you are fixing floor boards directly to joist you can either use secret nails or screws. These are applied using a purpose made nail gun or screw fixer which is set at a predetermined angle so that the groove of the next board can be fitted up without the screw or nail showing.  

Older homes in the Victorian and Edwardian era had joists over open ground with air bricks if the circulation is blocked then it can lead to serious damp problems. If you have enough height then a plywood base using 8’ x 4’ marine plywood can be screwed to the joists and the floor boards glued directly to the plywood. This will cut out drafts and prevent the damp air affecting the boards. If you do not have the height due to the levels in the house then you must always use an engineered board and ensure that all the ventilation openings and air bricks are clear

If you are unsure then our fitters would be happy to make a site visit to ascertain the best way of fixing your floor