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-   -   Can Attic With 2x4 Joists Be Used For Storage? (http://www.diychatroom.com/f19/can-attic-2x4-joists-used-storage-17087/)

TomBrooklyn 02-14-2008 07:08 PM

Can Attic With 2x4 Joists Be Used For Storage?
 
Is an attic with only 2x4 joists holding up the ceiling strong enough to use for storage.

i.e. Can it support an attic ladder and have some plywood put down and used as a storage area?

The studs in question span 16'. There is a wall under part of the attic which helps support the studs at approximately midspan. This is not a load bearing wall however. There is no matching wall on the first floor.

The roof is pitched about 7/12 and the roof rafters are 2x6. How about putting support bars between the roof rafters and the 2nd floor 2x4 joists to transfer some of the load to the stronger roof joists? Is this a crazy idea or marginally reasonable?

redline 02-15-2008 06:49 AM

How much weight will go up there?

jcalvin 02-15-2008 09:15 AM

As long as you space it out somewhat evenly and don't put a pool table or a grand piano up there, it will be okay. I have 2x4 trusses spanning a 26' garage and I have 2 sheets of 1/2 osb flooring with christmas lights, treestands, outgrown baby stuff... does fine.

Joe F 02-15-2008 09:46 AM

Are they joists or are they part of an engineered truss?

concretemasonry 02-15-2008 10:20 AM

If they are not trusses, I would not store anything except birds in birdcages.

Your ceilings will show it eventually.

Big Bob 02-15-2008 10:44 AM

Quote:

Originally Posted by concretemasonry (Post 98204)
If they are not trusses, I would not store anything except birds in birdcages.

Your ceilings will show it eventually.

:furious:

I second the above opin.

TomBrooklyn 02-15-2008 11:42 AM

Quote:

Originally Posted by redline (Post 98161)
How much weight will go up there?

Hi,
My friend originally wanted to include storage of some heavy stuff like a bookcase filled with books. I put the kabosh on that idea when I saw the conditions. They would still be satisfied to be able to store lighter stuff like clothes.

To be safe, some factor of safety needs to be considered though as someone might try to put more stuff up there then recommended and one wants to stay far away from the point of failure or even ceiling sagging and cracking. I'd be comfortable with a safety factor of 4.

TomBrooklyn 02-15-2008 11:51 AM

Quote:

Originally Posted by jcalvin (Post 98194)
I have 2x4 trusses spanning a 26' garage and I have 2 sheets of 1/2 osb flooring with christmas lights, treestands, outgrown baby stuff... does fine.

Hi jcalvin,
These are not trusses though. I was wondering if it would be practical and safe and legitimate as far as building codes to tie the ceiling to the roof rafters though to get them to carry some of the load. Even after that, I wouldn't recommend putting a lot of weight up there. But for fairly light stuff I thought that might work.

What if the weight were limited to no more than 120 lbs of stored stuff per sheet of plywood. Add a 200 lb person walking around and that would be 320 lbs/32sf sheet which would equal 10lbs/sf.

...just thinking out loud...not sure about any of this...

TomBrooklyn 02-15-2008 12:03 PM

Quote:

Originally Posted by Joe F (Post 98197)
Are they joists or are they part of an engineered truss?

Hi Joe,
Just joists. Basically they are designed to hold up nothing more than the ceiling. In the middle part and back part of the second floor there is the stairway, a hall, two bedrooms and a bath. To form those rooms, there is a wall, minus two door openings, at approximately the midpoint of the 16' wide house. To be more exact, it's probably around 6.5' from one side. This is not a bearing wall as it doesn't line up with a wall on the first floor, but it does serve to support the joists above and transfer some of it's load to the first floor joists.

In the front is a larger bedroom that is the whole width of the house which is 16'. That ceiling is already sagging a little under it's own weight. That shows that 2x4s joists alone are not really adequate just to support a lathe and plaster ceiling over a 16' span.

The proposed storage area would be in the middle and back part of the house where the center wall would help hold things up a bit, and like I wrote before, some ties could be made to the overhead roof rafters.

I have to find out if an attic ladder can be installed on 2x4 joists too. I suspect they're meant to be installed in joists at least 6" deep.

TomBrooklyn 02-15-2008 12:07 PM

Quote:

Originally Posted by concretemasonry (Post 98204)
If they are not trusses, I would not store anything except birds in birdcages. Your ceilings will show it eventually.

Hi concrete,
This is, of course, what I'm concerned about--or worse, if someone in the future didn't adhere to keeping the load light and put a bunch of heavy stuff up there.
Tom

concretemasonry 02-15-2008 12:50 PM

When you tie the joists to the roof rafters, you are putting more load on the roof and they may deflect even more, resulting in the ceiling deflecting.

There is no "magic skyhook" that can support everything.

Big Bob 02-15-2008 02:07 PM

It might be easier and more fun to build an addition or a storage shed then installing proper sized joists that run to your load bearing walls.

Are the ceilings under your proposed attic storage area wood lathe and Plaster?

TomBrooklyn 02-15-2008 06:38 PM

Hi Bob.
Yes to lathe and plaster.
I was wondering what it would take to install bigger joists. I don't know if I could fit them on top of the sill plate and under the roof.

Joe F 02-15-2008 07:11 PM

Something doesn't sound right to me. "Real" carpenters please weight in here, but I wouldn't think it's legal to span 16' with a 2x4, even if it's just supporting the ceiling. Is there a ridge beam supporting the roof?

woodman51jfk 02-15-2008 09:40 PM

.........older house obviously..........so 2X4 are probably dimensional.....if there is room to swing the boards into the attic space, you can sister the joists existing with 2X6. You said the rafters are 2X6, so there should be enough space to slide in the new joists, with a pitch cut to achieve maximum support on the top plates, if you need to splice them, use plywood or osb plates and overlap above the wall. This is only if the floor joists are trusses, lambeam or sistered 2X10, if not full length spans only. Add in extra insulation & overlay with 1/2' osb or plywood flooring. This is how I did the same thing in my 1929 "shotgun" ranch house...........local codes for you might not permit it unless an engineer signs off on it first........check that before lugging any sticks up there


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