Loft boarding - raising joists above insulation.

valve90210

valve90210

valve90210

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Having spent a chunk of today messing around in the loft hoping to get an area boarded and failing miserably as the previous owners have had new insulation installed meaning I need to raise the joists in order to clear the insulation I am asking for some advice.

I have read through several threads on various forums about this and seen mentioned many times loft stilts which have on the whole been met with disapproval, most seeming to prefer additional timber joists mounted on the original joists. This had been my initial plan but I was worried that the extra timber would be really heavy and along with the boarding and a load of stuff stored up in the loft might be too much for the joists to support?

Are my fears re the weight unfounded? If so I shall get some timber and get installing...

Any help very much appreciated.
 
The official answer should be get an engineer to look at the timber sizes and calculate if it's possible. I'd just do it unless I was planning to store anything substantially heavier than old clothes and normal loft junk.
 
Timber I beams, lightweight, used them in one of my previous places.

Got 10 9"x2" engineered timber beams for about £25 off the bay, laid them out & then laid a 18mm chipboard floor for storage.
 
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As long as you laid the new joists the opposite way to the existing loft joist, then the loading is taken by the walls below & transferred to the ground floor.
 
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Nightglow said:
Timber I beams, lightweight, used them in one of my previous places.
Click to expand...

Had a look for those but couldn't find many suppliers and the sizes didn't seem to match up with what I need, for ease I'll stick with timber like the previous owner used on the smal area he boarded.

Nightglow said:
As long as you laid the new joists the opposite way to the existing loft joist, then the loading is taken by the walls below & transferred to the ground floor.
Click to expand...

This is good to hear! :) I shall do it that way, as has been said I'm not looking to store anything very heavy, just usual sort of loft stuff,
 
I used a product called Loft Legs which are 170mm long plastic stilts with pilot holes for screws. They weren't cheap and you need a hell of a lot of them, but they made the job SO easy. I wouldn't bother faffing about cutting up wooden stilts again, having used them.
 
just done this myself, as discussed already joist over existing joists in the opposite direction, lay insulation, then board it out,

job done,

top tip, before doing this, make sure you wear a mask, and have overalls and gloves on, I also gaffa tape the gloves over the sleeves, this will prevent any itching later from the glass fibres,

that is of course if your using this type of insulation
 
Question regarding joisting over the existing joists: the insulation you use on the top is 170-200mm thick (or more), so don't you end up squashing the insulation down when you board over it? I only ask because it loses its effectiveness when you squash it down. Or are you using very deep joists on top?
 
I'm using fairly standard joists but the insulation that has been put down is not hugely deep so the boarding does squish it down but only very slightly....to be honest I think the insulation has been put down in a fairly shoddy manner as it looks a bit ropey, also I think it has been laid on top of old insulation which was not as deep as it should have been so overall it's not a deep as some.
 
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