Strengthen Roof Joists Loft Conversion

Joists insulation and boarding.

Strengthen roof joists loft conversion.

Existing loft joists are designed only to support ceiling boards so a structurally sound floor is needed. Lining walls and ceilings with a double layer of acoustic plasterboard can also be very effective as can laying a carpet over thick rubber underlay. Loft floors loft floor construction. The roof section requires 300mm of mineral wool insulation e g.

This method uses 100mm celotex insulation or similar over the rafters and a covering capping followed by the tile battens and tiles. One of the best materials for sound insulation is mineral wool in quilt or batt form which can be stuffed between floor joists or stud work in your loft conversion. Rockwool or 150mm of slab foam insulation such as celotex. The new floor also needs soundproofing and this is easily achieved by laying a mineral fibre quilt between the joists.

In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together side by side. Use the heavier denser sound insulation quilt and not the lighter thermal insulation material which is of no help here. If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists. Sound insulation for your new loft conversion.

Sistering is the process of adding a new joist next to each existing joist. Ceiling joists consist of two narrow low grade timbers often bolted together sistered above a supporting wall.