Loft legs vs 2 x 4

[Mart_]

Hi,

What's the general opinion of loft legs plus chipboard vs 2x4's across exisiting joists plus chipboard?

We want the loft boarded for general light storage. There's quite a lot of height and I plan to get rid of the existing dead rodent infested insulation so I have a clean slate to work from.

The more I read the more I worry about weight. I bought a few packs of chip board to stand on whilst fitting loft lights and didn't realise how heavy these things were, so coupled with a ceiling full makes me think, plastic loft legs are lighter than 2x4's ...... BUT THEN, I read 2x4's would strenghen the loft.

I aim for at least 270mm insulation or the celotex equivalent to get the R-Value.

Decisions, decisions, decisions?

Over to the experts, what do you think?

Thanks

 

[Tigercubrider]

I have no idea structurally. My house is mid 50's

i looked at loft legs. my joist spacing is rubbish for pre cut loft flooring.
Plus the depth was not a lot.

in the end I bought sheets of ply and OSB and had B&Q rip them lengthways to about 8" then bought some 2x1 and sort of made I beams that I fixed at right angles, spaced so that modern insulation and flooring fitted.

I have a lot up the loft, all seems well after 5 years.

 

[oldbutnotdead]

Not used those loft legs but they look really flimsy and they're expensive. In your shoes I'd go with 4 x 2- if you go to a decent timber merchant it'll end up costing you about the same as a loft full of plastic things

 

[Paulg31]

I'd got for the 2x4 option. It might be heavier than the loft legs but if you run them perpendicular to the ceiling joists it'll help distribute any loft loads better. Plus running them perpendicular to the ceiling joists will allow you to run insulation in both directions too.

 

[Doggit]

The problem with 2x4s is that you only get 200mm of insulation, so you really need 2x6s. But even if you use 2x4s, you're going to need to drill down into them to be able to get 6" screws into them. If you can get 2x2 unsawn, then you can easily drill and fix this perpendicular to the joists, then put down a bead of glue, and fix another 2x2 on top of it, and then screw down again. Much easier to handle, you can ovelap the joins, and once boarded, it'll have the same stability as 2x4s

 

[amthorpe2000]

I have no idea structurally. My house is mid 50's

i looked at loft legs. my joist spacing is rubbish for pre cut loft flooring.
Plus the depth was not a lot.

in the end I bought sheets of ply and OSB and had B&Q rip them lengthways to about 8" then bought some 2x1 and sort of made I beams that I fixed at right angles, spaced so that modern insulation and flooring fitted.

I have a lot up the loft, all seems well after 5 years.

Any chance of a photo. Did you consider a coring bit to lighten the web of the beam, though it probably wouldn't be much

 

[JohnD]

Any chance of a photo. Did you consider a coring bit to lighten the web of the beam, though it probably wouldn't be much

Did you intend to reply to this 8 year old thread?

 

[amthorpe2000]

Did you intend to reply to this 8 year old thread?

Yes. I asked an a new thread and had someone tell me to search so asking as its of interest and might be useful

 

[oldbutnotdead]

The relative cost of timber vs loft legs will have changed somewhat. Fixing 4 x 2 to existing- you can screw straight through (treat yourself to an impact driver and Torx head screws). You could use twist steels. You can use bits of 2 x 2 as corner posts. As for coring the 4 x 2- modern 4 x 2 is flimsy enough anyway, why would you weaken it deliberately?

 

[cdbe]

Better off with PIR sheets - 100mm upwards depending on budget, laid directly on the joists and over boarded with a thin sheet material such as hardboard - perfectly adequate for access and storage - no point loads, no thermal bridging and virtually no additional load.

 

[amthorpe2000]

The relative cost of timber vs loft legs will have changed somewhat. Fixing 4 x 2 to existing- you can screw straight through (treat yourself to an impact driver and Torx head screws). You could use twist steels. You can use bits of 2 x 2 as corner posts. As for coring the 4 x 2- modern 4 x 2 is flimsy enough anyway, why would you weaken it deliberately?

The original post had osb as the website not 4x2 hense the question on coring