Timber Joist Floor Insulation

A recent job forced me to think of a new affordable way to install floor insulation from above.

Timber joist floor insulation. Solid timber strutting to be at least 38mm thick and be a minimum of three quarters of the joist depth. A semi rigid material is generally best as it can be cut very slightly oversized and squeezed in between the floor joists thereby ensuring no draught causing gaps. If the insulation is soft insulation it can be suspended on netting fixed between the joists whereas rigid insulation can be sat on battens nailed to the side of the joists. This insulation is placed between the floor joists.

Proprietary strutting is to be used in accordance with manufacturers recommendations. Joist spans 2 5m to 4 5m provide strutting at mid span. Any compromised floorboards or joists can also be replaced as part of the retrofit project. Separating floor insulation timber joist separating floors the primary purpose of a separating floor is to provide acoustic separation for both airborne and impact sound between two adjacent dwellings thereby improving the acoustic comfort of both dwellings.

All ground floor constructions unless very large commercial floors will require some insulation to be included within the floor zone to comply with building regulation requirements. All the figures are based on normal domestic floor loadings where the floor construction is typically 18 25mm floor boards sheets with up to 12 5mm thick plasterboard and skim underneath. In some cases if the floor is accessible from below it may also be possible to partially insulate the joists from underneath which offsets thermal bridging through timber members but this is not often the case. I would also suggest that to cut down thermally diminishing air movement around insulation you install fibrous insulation between the timber joist such as mineral wool or sheep s wool to take up any seasonal movement in the timber floor joists as the quickest insulation method.

And this video shares the insight that i attribute to the lo. Insulation wall insulation loft roof insulation floor insulation insulation accessories. Mouldings planed timber planed timber mouldings skirting cladding wood flooring window boards. If the ground floor in question is of a suspended timber construction and whether this is a renovation or new build project then the insulation would normally be installed in the joist zone that is installed between the joists.

Kiln dried treated carcassing 9. At least 25mm of the joist must be left exposed to ensure air circulation. Joist spans over 4 5m provide 2 rows of strutting at third span positions. The insulation should be pushed tight to the underside of the floorboards.