Working on a lead shed - floor support?

[RogerDat]

I'm building a shed in the back yard of course it will be for the typical lawn and garden stuff but it will also be home for a fair amount of lead if the floor can take it. I would guess that lead storage could be as much as 1000 - 1500 lbs.

I'm wondering if others with experience storing lead in a garden shed or more construction knowledge would know if sagging or extreme settling would result from storing the lead there. Have heard of folks cracking the garage floor with too much lead stacked in one spot so I may (depending on advice from here) keep the lead in the garage and move something lighter from the garage to the shed.

Planning to use 2x8 on 16 inch centers for floor joist, span is 10 foot. 5/8 inch OSB floor material. Floor framework is to be on 2 inch thick concrete blocks to give it some air flow underneath, with the pad being crushed limestone 5 inches thick compacted with a lawn roller.

Have the option (until tomorrow afternoon) of adding additional floor joists or more concrete blocks to help support the weight. Would really hate to move all those buckets out to the shed and come spring find a disaster. But don't really need all of that stash in the garage.

[bruce381]

no expert but I would put the foundation block close maybe also on 16-24 inch centers?

[MaryB]

My 12x16' shed is 2x10 floor on full length timbers spaced 4 feet apart running opposite the joists for support. I had 6,000 pounds of corn stored on the floor one winter with no issues.

[dragonrider]

Shed dimensions are 10 by ?? Go with joists on 12 inch centers, won't cost that much more. And double your osb floor.

[shoot-n-lead]

I store mine in drums, outside of my building.

Not willing to take up my expensive space to store lead.

[finishman2000]

I just poured concrete for the floor to my shed. a little more money but no worries.

[Petrol & Powder]

You're transferring the load from the floor to the ground via the joists and the concrete blocks. The two places you could have trouble is the strength of the joist and the pressure placed on the concrete blocks. If the joist is only supported on the ends, you are transferring all of the load to the two ends and then down to the earth via the blocks. The simplest and cheapest insurance would be to decrease the centers and add concrete blocks to reduce the unsupported distance of the spans. Someone else suggested 12" centers for the joists and I think that would be far better than 16" centers when using 2"x8"s.
The more concrete blocks you add the shorter the unsupported spans become but it becomes difficult to get all of the blocks at exactly the same level. The load is essentially trying to push the block into the ground. Because the block has a relatively large surface area that load is spread out over a large area. A large flat block can support a tremendous load.

[dragon813gt]

You need to spread the load out. Beefing up the support structure isn't going to hurt anything. The key is to spread the load across as many joists as possible. You can accomplish this by simply building a holder for your lead. Span 2x4s, or larger, perpendicular to the joists. This is all you need to do. I would stand the 2x4s up and build a box on top of them. The more joists it spans the more the load is spread out. Of course you need to stack the load evenly. I would not place the load directly on the deck regardless of the structure.

[pworley1]

Unless you store all your lead in the middle of the room you should be just fine. With the lead stored against one end and that end supported by blocks, the blocks will be supporting most of the weight.

[RogerDat]

Lots of good information. Thanks. Shed over all is 10 x 16. Wide and shallow.

I think 12 inch centers makes a lot of sense. Only 3 extra 2x8 joists so not much cost. Sounds like some extra blocks across the middle to shorten the 10 ft. span to 5 ft. would do much the same thing that MaryB accomplished with her cross timbers. I'm thinking of one every 4 feet across the middle. Enough to add some support but not so many that leveling is too painful. The crushed stone base is a little bit adjustable to get the blocks level.

Thought about concrete, have an in-law that does concrete and block work, rough price for concrete and labor on the family plan was $1000 and the additional excavating work for footings would probably pushed it beyond what grandson and myself could do with shovels. My back charges a heavy toll on picking up a shovel these days. That is why I tend to keep my lead containers down around 50# I can handle 78# buckets ok if I don't have to move them far. So I'm figuring the weight can be spread out a bit.

Good point about using expensive space to store lead. I have to consider that the same dear woman that will allow me to sort WW's in the living room watching TV if I put down a drop cloth (and clean up after myself) balks at loose "stuff" stored outside. If I want to store lead outside I'll have to build a bin to keep it nice looking. Actually that would be a good project to consider... for later.

[RogerDat]

Like the idea of putting a cross pieces under the weight to spread it across more joists. If it spans to another joist with a center support that should work well.

[725]

I'd dig additional holes and set 4x4's under the area of increased weight. Span a couple floor joists with cripple joists and support from below. That'll hold literally tons.

[Dan Cash]

1200 lbs lead does not take up much room, especially when in uniform ingots and stacked. Get a 55 gallon barrel and fill it up. Holes in the bottom for drainage or put a lid on it.

[Alan in Vermont]

Are you planning to use pressure treated (PT) lumber for the floor framing? Untreated construction grade lumber isn't going to do well being that close to the ground.

On the same note, OSB isn't very durable in a damp environment. 3/4" PT plywood, laid so the grain is perpendicular to the joists would last much longer.

I would really reconsider doing this on a slab. Granted it's more money up front but permanent. there is also the advantage that the floor ends up being closer to ground level so there is less height to lift anything heavy over to get stuff into the shed.

To help with moisture issues it would be prudent to get some form of vapor barrier under your stone base or under the slab if you decided to go that route. I would use two layers of 4 mil polyethylene, 6 mil would be better if you can find it.

The greater the number of support points the better. Not knowing what your soil is like I can't offer any solid (no pun intended) suggestions but an 8X16" block is only .88 sq. ft. of area. Some sandy soils are only good for 1,000 lb/sf static load. Clay soils vary but damp clay may not be much better than that. Your stone base, with only a lawn roller for compaction isn't going to gain you a lot in terms of load bearing. Even properly compacted it will lose some of it's density due to freeze/thaw cycles. I will assume you're using a stone product that has various sizes of stone from 3/4-1" down to dust. If you use graded stone, all one size, it never does compact worth beans.

[clintsfolly]

A con for concrete is you now have a permanent shed and the tax man Will get you. A temporary shed is non taxable. You can use the saved tax money to buy more lead Clint

[Recruit]

I would just box off a section of your floor joists and fill with concrete. Simple and sure.

[RogerDat]

Yes PT lumber, crushed rock includes everything down to fine. Soil is a loamy clay, packed well. Water tends to flow across that part of the yard (slopes a bit) so I was going for gravel drainage, with blocks to elevate and provide air flow under floor. Did not put moisture barrier in ground since I want the water to "move down" through the gravel but was thinking of one under the floor deck and over the joists. Concluded that air flow beat risk of trapping moisture, but that was just a SWAG.

Am liking the approach suggested here of running some lumber on the floor across the joists. I can make shelves where bottom shelf is the lumber across the floor.

Plywood better than OSB but man the prices, was a tough call. Paying cash and there is a limit to how far I'm willing to draw down savings. Hope I don't regret that decision later.

Well coffee break is over back to work!

[Petrol & Powder]

12" centers And spans of 5' will work just fine.

[dragon813gt]

OSB will swell a lot if exposed to moisture. If it's left exposed OSB should not be used. I would put tyvek underneath for a moisture barrier. Holds up better than plastic, but it does cost more money.

[RogerDat]

So what side of OSB would you put toward the ground? One side shows more "chip" grain the other has more glue texture and markings. I was thinking chip side up. Will have to paint floor I think to avoid moisture from soaking in when something wet is brought inside or if the door gets left open and it gets some rain inside.

I have to make a lumber run here in a little bit, will check on tyvek prices when I'm at the store, as I recall tyvek does breath a bit and had not considered it.