Can someone help me Strengthen the joists in the loft.

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Im looking at flooring my loft and i have been told i would need to strengthen the joists as they are 50mm deep how do i go about strengthening these i was told that all i would need to do would be get lengths of wood and strut then together via bolt's but this doesnt seem too easy to do. I had 3 quotes for getting the loft done and unfortunately they have all come in at over £5000.

Could someone help me :confused: [/b]
 
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Is this just to strengthen it for storage, or are you looking to use it as a room?

If the former, screw-fixing 19 ply at close centres near the supports, increasing the spacing towards the centre of the span, will greatly increase the stiffness of the floor.

If you're making it into accomodation, though, you will need to put new joists alongside the existing to cater for the increased occupancy loading. You can set these 10mm or so above the existing ceiling and nail the existing joists to the new ones - they don't need bolting.
 
Is this just to strengthen it for storage, or are you looking to use it as a room?

If the former, screw-fixing 19 ply at close centres near the supports, increasing the spacing towards the centre of the span, will greatly increase the stiffness of the floor.

If you're making it into accomodation, though, you will need to put new joists alongside the existing to cater for the increased occupancy loading. You can set these 10mm or so above the existing ceiling and nail the existing joists to the new ones - they don't need bolting.

So is this pretty easy to do then ?
 
why don't you want to answer Shy's question?
 
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why don't you want to answer Shy's question?

Sorry john thought i had answered it, I looking for this to be mainly storage, but it would be have to hold some heavy things aswell. Just this will be the first major project ive done.
 
my loft is made of trusses, and I have cross-battened it with 70x35 ish timbers, at right angles to the trusses. This spreads the load across several when I am clambering about. Extra insulation goes between the battens, and boards are on top. It is all screwed together and this improves rigidity and spreads the load, but does not increase overall strength of the ceiiling you are standing on, so not much weight goes up there.

However Shy is a Structural Engineer so knows more about it.

It would be very helpful to know the contruction of your roof and see some pictures of it.

If it is a small house with a Victorian roof made to carry slates it will be very flimsy.
 
Sorry, I forgot to pop back in on this thread.

JD's method is fine with trusses, due to the construction; but it's less successful with older cut roofs, as there is a lack of all the elements being tied together.

However, if you've got an older, cut roof structure, ply screwed down on the top of the existing joists and sticking your more heavy stuff close to (or over) the binders (timbers that run at right angles to the joists and over the top of them) will help to limit the deflection that would otherwise occur if you did nothing.

What sort of weight are you thinking of sticking up there, ooi?

As JD says, some pix would be helpful, to give you more specific advice.
 
Sorry, I forgot to pop back in on this thread.

JD's method is fine with trusses, due to the construction; but it's less successful with older cut roofs, as there is a lack of all the elements being tied together.

However, if you've got an older, cut roof structure, ply screwed down on the top of the existing joists and sticking your more heavy stuff close to (or over) the binders (timbers that run at right angles to the joists and over the top of them) will help to limit the deflection that would otherwise occur if you did nothing.

What sort of weight are you thinking of sticking up there, ooi?

As JD says, some pix would be helpful, to give you more specific advice.

Thanks for the help guys i will try and get pics this weekend and post them on here or summat, its a house built in the 1950's ish in scotland and an ex council house aswell, the trusses i think they are called are of a W style i have 3 of them.

weight wise its stuff like all my old football programmes (there's a few) and just the usual stuff, like golf clubs, suitcases a couple of old small 14" tv's and my computer base units

hope this helps
 
They're TDA trusses, probably about 9' centres or so. Don't go cutting them out!

As for the stuff you mention, that's not a major problem - even with some board just loose-laid over the ex joists. The paper is likely to be the most weight, depends on just how sad and how many progs you've collected ;) - just put them close to the binders.
 
They're TDA trusses, probably about 9' centres or so. Don't go cutting them out!

As for the stuff you mention, that's not a major problem - even with some board just loose-laid over the ex joists. The paper is likely to be the most weight, depends on just how sad and how many progs you've collected ;) - just put them close to the binders.

Coll cheers shy, just when i was told by people who would have been flooring the loft they are saying i would need to strengthen the joist as they wont take any weight but they seem to when im up there.
I will still get the pics and show them to you guy's

cheers
baz
 
They'll take more load with a board down, as that spreads the load, whereas without it, you put load on one joist and it can't spread, as plasterboard (or lath and plaster) on the underside won't influence that.

If they take your weight standing one one joist, then there's not really anything to worry about in respect of stacking the stuff you want to up there, particularly with some board over the top.
 
How about take a pic of in the loft
then take a pic of everything you want to put in there & let this lot advise better?
 

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