Loft boarding question

PeteW

I’m boarding my loft and have 38mm wide rafters spaced 380mm apart.
The loft boards I have are 1220x320 mm.

So, assuming I want each board to start and end on a rafter (for stability), I’m going to have to chop off over 30% from each and every board I’ve bought and throw it away - is that right or am I missing something? From what I can tell the above dimensions are standard sizes, but surely the boards aren’t designed to be used like this?

See the image here to see what I mean - top is how the full sized board would lie, bottom is chopping each board down to fit.

nofoollikeold

1. I assume you are boarding over the joists, not the rafters.
2. The simplest thing is to cut the boards as you suggest.
3. Alternatively you can insert cross pieces (of, say 2" x 2") to support the long edges where there would otherwise be a cut. If you do this, don't cut into the joists to fix, use brackets of some sort. Probably work out more costly than wasting the loft board pieces.
4. Before doing any of it, consider that you may need loft insulation spacers if you want the full recommended thickness of insulation.

TRB

If the boards are tongue and groove they should be ok to span without cutting .

TheCyclingProgrammer

Older houses can have oddly or irregular spaced joists. If there's enough room, I think some cross supports (I'd use 3x2) laid at 400mm centres would make your life much easier and make the floor more rigid, just bear in mind the extra weight. We had to do it in our loft as the joist spacings were all over the place. It would also give you some more room for insulation underneath but remember you'll need to leave an air gap for cross-ventilation.

stator

If it's just for one person walking around the loft then you'll get away without chopping them, as long as the boards are interleaved and you don't damage the tongue and groove.
At the edges, where each board is only attached sideways to one other board (instead of two) you might want to support it with a bit of timber screwed into the joist.

glasgowdan

Place boards at right angles on top of the unsupported edges to span 4 boards. The weight will be spread

TRB

Just to double cheque I asked the carpenter at work and he said the boards are designed to be self supporting .

stator

It's true, but only for their intended purpose!
If you want to store heavy stuff on top, or have lots of people up there at once, they aren't suitable.

PeteW

Thanks all. Will try self-supporting but with cross supports at the edges.

leveller2911

PeteW wrote: »

Thanks all. Will try self-supporting but with cross supports at the edges.

If they are chipboard flooring sheets then they are designed with the tongue and grooved ends. The idea being you put plenty of PVA glue in the joint and then fix the boards down with screws/nails etc, no need to fit any supporting battens under the end joints. Then the next row of boards you stagger the joints.....You will notice the end joint between two boards is then supported by the tongue/groove on the longest edges of the next boards.