Loft boarding advice

[dave2506]

I intend to board a small area of my loft to provide additional storage space at home. As there is already around 30cm of insulation up there, I will need to build some sort of suspended floor frame on which to fix loft boards.

What size and grade timber is required for such an application - ie to construct the frame? The frame will be hung each side from the main structural beams in the roof space - will this be OK?

For info the house is a 1930s semi and hence I will not need to remove anything from the loft structure to create extra space! I just need to know that effectively hanging new joists from the 2 main beams will be OK.

 

[PrenticeBoyofDerry]

The depth of the timber will depend what size/depth your existing joist are.
It is now recommended that 270mm insulation is used for lofts.
So measure the joist and then buy suitable depth timbers to make up the difference.
ie. If the existing joist are 100mm deep and you required 270mm of insulation, you would want additional timbers that are about 170mm deep.
If you lay and fix these timbers at right angles to your existing joists, this will help keep them secure and well supported, that will do.
So some timbers at 170mmx50mm, should be okay. Don't need anything special, soft would will do the job.

 

[dave2506]

Thanks for that - your suggestion makes much more sense than what I was orginally thinking lol. I will have a look up there one night this week and measure up to work out how much timber I will need to buy.

 

[PrenticeBoyofDerry]

Your loft boards will come in two different lengths either 1220mm or 2400mm.
So when installing you raise joist, take this into consideration.
It is common practise to run your joist every 400mm(this will suit the 2400mm boards), the 400mm measurement is to the centre of the joists, this will allow for the joist to overlap when the next board is butted up.
But your first measure from your first joist fitted, which will be on the perimitter wall should be taken from the wall, then 400mm to the centre of the next joist, then 400mm to the next centre and so on.
Hope that made sense.

 

[dave2506]

That does make sense - thanks. I will be using 1220mm loft boards so 400mm spacing between the new joists will be fine. Given that it is a loft floor, will 600mm spacing be alright? That way I can stagger the joins in the loft boards in each row (if that makes sense?) and save myself a bit of money on the timber.

Given that I'm also fitting a new, larger loft hatch with ladder, do you think a weekend will be enough time to complete the job? I'm recruiting help from a friend and father in law

 

[PrenticeBoyofDerry]

No 600mm is not recommended, stick with the 400mm centres.
If you go 600mm the floor will not be suitably supported and will flex, and the boards will come under much more stress from any foot traffic or heavy objects and could break/snap.
It is worth that little extra.
Even with 1220 boards, you will be able to stagger them, may mean cutting your first board but it can be done.
If you have ever laid a laminate floor, use the last cut to start your next row, providing it is in excess of the 400mm that is, and cut it down according to your joist centres.