Fitting Floor Joists Extension

New floor joists are measured and trimmed to size then dropped into the joist hangers and secured in position.

Fitting floor joists extension.

Once the joist was vertical it would fit fine hence the slight floor jacking. In buildings with basements the first level of floor joists serves the same purpose. If i cut the joist to fit that gap i believe i simply wouldn t have enough material in play to resist shearing stresses. This size is no longer acceptable when framing a structure.

The reason was the corners of the new joist when at a 45 degree angle caught the top of the beam and the bottom of the floor boards. I m having a single storey extension built approx 4m x 5 8m. What i am after is something like a reverse joist hanger. The new joist fit in the space sideways but would not tilt into vertical position.

From what i can guess this doesn t seem like enough space to try and fit an 8 joist into. Decide whether you wish to set the joists so that they run over a beam butt together over the beam or fit them into hangers attached to the sides of the beams. Spacer noggins solid struts are installed between joists to reduce joist deflection vibration improve floor rigidity and performance. Fit the joists into the joists hangers if you choose that method of installing floor joists.

Standard practice in the uk is to raise the new floor joists 12 5 or 19mm inch or inch above the underside of the existing ceiling joists. Regardless you should check and confirm new floor joist size with your local building control authority before proceeding. In the past 2x4s or 2x6s were sometimes used as floor joists. Lay out your joists so that they will be spaced 40 cm 16 inches on centre.

The builder inserted the air bricks and dpc too high which meant that when he put in the floor joists hung off ledger boards bolted directly to the blockwork the ledger boards covered the air bricks and all the timbers were below the dpc. Floor joists installed on second or third or higher levels double as ceiling joists for the level below.