boarding loft with loft legs but 450mm centres

Solus

Solus

Solus

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Can anyone advise me of the most effective way of using loft legs to board out my loft?

It would be simple with 400 or 600mm centres but I have 450!

This means each 1220mm loft board I'd be cutting off 320mm of length, which would be a hell of a waste and would involve a skip or numerous tip runs. Not to mentionit would take an age just putting down 900mm of board and cutting each one.

Any better ideas?
 
Run the boards at 90 degrees to the joists and set the stilts at the board width.
Its reckoned you can have a 200mm overhang from a stilt to the end of the board.
I used boards that were tongue and grooved on the ends as well, if you cant find any then I would be screwing a strip of timber under the ends as additional support.
 
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I see. So it is allowed to have an overhang, I'll have to do some calculations to work out if the overhang would ever be more than 200mm
 
Solus said:
I see. So it is allowed to have an overhang, I'll have to do some calculations to work out if the overhang would ever be more than 200mm
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A significant overhang is not a good idea unless you're using thick planks of solid wood - definitely not chipboard! And yes, I have put my foot through!

What you can do is put down batons underneath the floor at an appropriate spacing (across the whole loft) so you effectively have two layers. 1cm thick should do it. Again you want wood, not chipboard or MDF et al for these batons. This will also help if you want to put wiring in by providing a space between the joists and the loft floor.
 
If you stagger the boards the butt joints wont all line up and the edge tongue and groves will help to support.
I would be happier with a piece screwed under both ends of overhanging butt joints personally.
 
Finally got down to pricing all of this up today.

I could either get british gas out (if i remove the 100mm insulation that's up there), lay loft legs (I need 275 of them, 23 packs!), then they would lay 270mm of insulation.

I would gain from insulation but the cost of the loft legs over 4x2 timber is £100 more, coming out at £299 for loft legs alone.

I could keep the insulation as it is, run extra 4x2 joists 90 degree to the current joists at 600 centres, this would cost £190 in timber. I would have extra height and the added benefit of being able to attach flooring to the purlins, as they are exactly 4 inches high from the joists, making the job take less time.

Unfortunately, there are some cables running over the purlins also, requiring me to notch out for these in the purlins, does anybody know if this is allowed?
 
Is my idea safe?

Will the existing joists be able to hold up 4x2" timber at right angles on top?
 
Solus said:
I know what I'm doing, just wanted to be sure it wouldnt bring the ceiling down.
Click to expand...

lol, the reads brilliantly! I'd just get on with it as it appears to me you are over thinking the whole thing it's boarding out a loft for storage not building a house!
 
its suprising how much weight timbers can hold.

we install things at work onto timber ceilings for people that weigh upto 42 stone.
 
Thanks for all responses. If I'm honest I would have done it but I had an electrician in to fit lighting up there in preparation for beginning the job.

He said he wouldn't lay 4x2 over the joists as he has apparantly seen it cause damage to the plasterboard below.

This is what has made me stand back a bit and question my method.

Yeah ceilings are in, loft hatch will only take 500mm widths, so I'm looking at the 300mm stuff only.
 
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I plan to remove the standard insulation and use something like celotex, that way i dont need to raise anything and just lay the boards on the joists. Celotex is more efficient so doesnt need anywhere near the same thickness of material.
 
I'm well underway with this project now.

I had nice evenly spaced purlings running right along the length of the whole attic above the ceiling joists.

I used 3.7m lengths of 4x2 timber (I ordered 13x 4.2m 4x2's and cut them).

I then layed them at 610cm centres (loft boards are 320mm x 1220mm).

I then bought 4x knauf roll insulation currently on offer in Wickes 2 for £30 and layed this.

I am simply now boarding over the top. Here's a photo of my progress:
 
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