Attic Conversion Floor Joists

Clearing the loft area of all debris insulation struts and temporary boards to expose the ceiling boards.

Attic conversion floor joists.

The floor framework is mostly made of wood joints running parallel to one another at regular intervals. We currently have 2x6 floor joist that span 16 on one side and 18 on another. If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists. New homes install i beam shaped joists.

The new floor joists of your loft conversion will need to offer at least 30 minutes worth of fire protection which could mean replastering the ceilings in those first floor rooms below. In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together side by side. Fortunately this is a fairly easy fix. You can sister the joists by cutting 2 x8 boards the same length as the joists applying construction adhesive and affixing each to a joist with nails.

Most floor joists are typically spaced 2 by 8s 2 by 10s and 2 by 12s. This means that new floor joists are fitted alongside them slightly raised above the ceiling plasterboard to avoid contact with it. All meeting up on the load wall. A new floor system is installed using a frame trimmer joists to support the floor joists that span the width of the loft.

You might open up your attic and find bare joists with fiberglass or cellulose insulation between the joists. When joists spacings are wider they should be deeper as well to limit stress and deflection under the load. In this video i show how i cut my my joists make packer plates get the joists from the garden up int. Sistering is the process of adding a new joist next to each existing joist.

This is part 2 in my series of loft conversion videos. A basic floor system is installed in about 10 stages from preparation to boarding the floor. All our current 2x6 joist are spaced 16 on center. There are many ways of altering roof structures for loft conversions but they all have one common element the ceiling joists will almost certainly be inadequate as floor joists.

If your attic joists won t bear the weight necessary to finish out a living space but the engineer cleared them to support floor decking for light storage you can install inch plywood or.