Loft Conversion Floor Strengthening

If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists.

Loft conversion floor strengthening. 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. Sistering is the process of adding a new joist next to each existing joist. This method ensures the thermal insulation level is maintained and your u value is not compromised. Full length timbers are used for additional strength.

This is part 2 in my series of loft conversion videos. It also provides protection against stress on the ceilings beneath. Joist cross bracing is used to elevate the floor above the existing insulation by 100mm. You can do this by adding larger and stronger timber floor joists between the existing ceiling joists.

Even if the loft was previously used for light storage you will almost certainly have to strengthen the ceiling joists in the loft floor. The plan is just to put down some 18mm chipboard insulate the roof and board off the roof and eaves. In this video i show how i cut my my joists make packer plates get the joists from the garden up int.