Help a newbie with loft boarding :)

7 Jan 2009
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United Kingdom
Lo there - new member here!

I've got a 1929 semi, with a loft I'd like to (better) use for storage. I've had quotes to get the roof relined & retiled (as the existing tiles are torched on(?) and crumbly - and also get a loft ladder installed.

Once those are done, I'd like to properly board the loft - but I'm not sure how amusing a prospect this is going to be, given the state of the loft - here are some questions, if you'd be so kind as to assist :)

Existing ceiling "floor" joists are 2"x3", (3 inch side vertical), and spaced 13" to 14" apart (see pic).

I gather from reading various sites that 2" x 4" would be better, but given the spacing, would I be ok to board "as is"?

Also, either side of the loft is a 2"x3" joist on top of the other joists, running the opposite way (again, see pic).

My initial ("I'm not a builder!") solution was to add additional 2"x3" or 2" x 4" beam/sections (as I'd never get a full length one in - it'd have to be in at least two halves) across the main (lower) joists, to better distribute weight, and then lay the floor boards across those (so they would cover the raised/highest joist).

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Picture above shows the 2"x3" joists, the gaps between them and one of the two crossways 2"x3" which is atop them (yes, I'm aware it's a bloody dusty mess - hence why the roof is intended to be done!)

Is this a completely mad idea? (Where) Do I need to worry about weight? Should I suspend my intended crossways joists from the roof joists in some manner?

Do building reg approvals come in if I start diddling with joists? Or only if I tamper with the existing ones, rather than add new ones?

Help! (please!) :)
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I've got a similar aged bungalow with a similar loft joist design. 2x3 inch joists running across the 4.6m (17 feet) span, spaced at just over 12inches apart. there are some further 2x3 inch beams running across these, i think mostly for load spreading.

I've got loads of boarding up there already, though i'm not happy with it as a storage area. you can feel the joists bend under your weight (i'm only about 12 stone, so not exactly a big guy) as you move around, so no chance of storing anything heavy up there. not unless you want a dipping ceiling in the rooms below. the only place i can store heavy stuff is where an internal wall supports the joist just beside the loft hatch. don't think i'd dare carry a heavy item across the floor.

i'm about to up the insulation depth from 70mm-ish to 270mm via the eon offer thats on atm. this means emptying the loft and pulling up all the boards.

after that is done i want to put boards back, which means finding a way to get the joist height up to 270mm. preferably a bit more so i don't start squashing the air out of the insulation.

so i think my only options are either laying addition beams on top of my original joists, or sistering a new joist in along side. neither option seems a good solution right now.

sistering joists in would need me to find a way to get a 5m-ish long 300mm tall joist into the loft, probably by making a hole in the roof somewhere. tapering the ends to fit under the slope of the roof and figuring out what to do about the existing load spreader beams and other stuff that would be in the way (water tanks, flues and other stuff i've no doubt forgotten). i believe you are also supposed to fix the ceiling to the new joists, which as i mostly have timber batten ceilings, i have no idea how to do without causing a huge ceiling job too.

laying additional wood on top of the existing joists seems easier. but again is the challenge of getting the new wood up there in the first place. if i got it in shorter lengths, what do you do for joints between the lengths? if its not a single length, surely its more resting its weight on the existing joist then adding any additional strength. again, how do i go round the existing obstacles?

even with these issues resolved, there is still the cost involved. the loft is about 78 feet long, so that is an awful lot of additional joist wood just to achieve some storage.

maybe i should just build a shed instead?

any advice gratefully received
I think you both have to face the fact that your joists are fit for their designed purpose and not a lot more. IMHO you should fit your loft insulation and buy a shed.
Came up with a possible solution to the problem. No idea about the OPs house layout, but mine has internal brick walls partitioning up the space into rooms. These can be used as the base to build a new storage platform in the loft which is independent of the existing ceiling joists.

I have internal brick/block walls which are parallel to each other about 3m apart. If i lay timber on top of the internal walls up to a height of say 200mm above the back of the ceiling, forming an over sized wall plate. I can then lay 100mm joists between these wall plates and be above all the existing ceiling joists etc. It also leaves space for 270mm of insulation plus 30mm air gap under any boarding i put down on top of the new platform.

would just need to check the span to spacing to load for the 100mm joists to ensure a suitable strong platform is built for storage.

what do the experts of the forum think?
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If the new storage floor will be supported by masonry walls that are not supporting anything else, it should be OK. However, I have a feeling that the internal walls are there to support the ceiling joists, hence their small size. This should not be a problem provided that the weight of the new floor structure and storage does not push the walls down, away from the bottom of the ceiling joists, which will then be at considerably more than their original span. My advice: for a hundred or so quid, ask a structural engineer.

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