Need construction advice for huge shelf

[BarnyardChaos]

So first I'm sorry this question is totally unrelated to chickens or coop construction, but I have a conundrum and I know there are a roomful of construction experts in this forum. So may I ask for some advice, please?

I need to build a shelf. A BIG one. It's to span over a bank of refrigerator and freezers in our storage room. It cannot 'rest' on top of the appliances, obviously, but needs to be supported on the ends and edges only. It will fill the end of the room, 132" wide corner-to-corner, and 30-32" deep. I will store lightweight, bulky things on top, such as blankets and pillows, bulk toilet paper and paper towels, and empty totes and coolers - maybe 300-400 lbs. total. Of course I need to maintain air flow around the appliances as well. There's very little space to add vertical supports on each end, and doubtful if I can put a support pole in the center (I'd rather not, if possible).

I'd like to use what I have on-hand as much as possible. I have a whole pile of used 2x4's and 4x8 wood siding panels at my disposal. I'm aware I'd have to buy a couple of 12-ft long pieces of lumber for front and back edges. But I cannot find anywhere around here with 12' long plywood, and anyway that's a whole lot of weight and awkwardness to try to wrestle into place for a 63-yo woman doing it myself. I'm handy with tools and have the necessary circular saw, power drills, carpenter square, stud-finder, etc.

Here's the room:

And here are a couple of sketches of what I think it might look like:

I can rest the corners of the frame on top of 2x4's attached to the walls to help with stability, though I cannot decide if I must wrestle sections of plywood or siding up there, or if I can do it with 1x12 boards cut in the 30-inch direction. I used the "Sagulator" suggested by @saysfaa here https://woodbin.com/calcs/sagulator/ and it would be a piece of cake IF I could get my hands on a 12' long sheet of plywood, OSB or siding, AND wrestle that monster up to the shelf supports. Not happening. I could do it with one 4x8 sheet in sections (one piece 30" x 96" and two fill-in sections at each end of 30" x 18"), or better yet, planks (1x12x30", about 12 of them). But I am completely unsure if the front horizontal board could support the weight safely if the shelf material isn't all in one piece.

Advice, please?

 

[woodworm]

I'd imagine at that span it's going to sag without a support in the middle. Ideally I think you'd add additional cross supports to help support the shelf, but that will add to the weight. Can you take a support upwards to a ceiling joist?

What are the walls made of - stud / plasterboard or brick? And is that a window behind the fridges?

 

[BarnyardChaos]

I'd imagine at that span it's going to sag without a support in the middle. Ideally I think you'd add additional cross supports to help support the shelf, but that will add to the weight. Can you take a support upwards to a ceiling joist?

What are the walls made of - stud / plasterboard or brick? And is that a window behind the fridges?

I was thinking to add a third 2x4x12' across the span, in the center.
I don't know about a ceiling joist, that's a thought - though (sigh) I really really really hate drywall work, and I'd have to cut a section out to attach it. I might be able to add vertical support board between the middle two freezers, or a 3/4" black pipe if it's just too much of a squeeze.
Walls are wood studs with lath and plaster. Ick. But I can work with that since all I have to do is locate studs and drill through. It's one reason I suggested corner supports.
Yes, that's a window behind the freezers. It will be going away when we put new siding on the house in a year or two. For now, I plan to remove the molding and just cover it with a cellular shade.

 

[Captain13]

You wouldn’t have to cut any drywall to attach the shelf to the ceiling. Suspend it with threaded rod.

 

[BarnyardChaos]

You wouldn’t have to cut any drywall to attach the shelf to the ceiling. Suspend it with threaded rod.

I hadn't thought of that option. It would require an attic rat (my grandson maybe) to crawl up there and nail a support board across a couple of joists, to attach the allthread to. Would that work?

 

[BarnyardChaos]

More info: The combined width of all the appliances is 127". The space is 132", so that leaves 5" wiggle room. Manufacturers say minimum side clearance is 1/2", but with freezer next to freezer, I believe I'd have to double that to 1" between freezers to prevent overheating. So there you have it. I have no room for vertical supports except to go through the ceiling. Might convince my son to help.

 

[Captain13]

I hadn't thought of that option. It would require an attic rat (my grandson maybe) to crawl up there and nail a support board across a couple of joists, to attach the allthread to. Would that work?

Yessir. It would be good for both of you to do a job like that.

 

[BarnyardChaos]

thank you both @woodworm and @Captain13 for your help!

 

[BarnyardChaos]

Question, again: Would it be possible to suspend the front edge of the shelf from lag screw eye bolts into separate ceiling joists and steel cable or chain? We used a porch swing for years suspended from a single ceiling joist and two lag screw eye bolts.
Like these:

lag screw eye bolts for the upper attachment, wall or ceiling

eye BOLTS for the shelf

But instead of going into the ceiling joist horizontally (as pictured), can I screw it vertically into the joists from below? My joists run perpendicular to the shelf, so they'd be in separate joists.

OR, would it be possible to attach the lag screw eye bolts into the header at the top of the wall behind the shelf (avoiding joists altogether), angling across to the front of the shelf? Shelf is 30" deep and 16" down from the ceiling surface to top edge of the 2x4 horizontal front support. Too low of an angle?

I'm really reaching to find a way to attach it without crawling into the attic space. You see, the access door to that attic is small. Too small for my son to squeeze through and my grandson is too young yet.

If all other options won't work, I think I will have to (a) cut and enlarge the attic access opening, or (b) cut holes in the ceiling drywall. I'm sorry to keep picking at this, but I need to have a solid picture of all the options available. Thanks for your time and expertise.

 

[Captain13]

Screwing into the ceiling joists from below with an eye bolt would work with cables just fine. Use a stud finder to get in the center of the joist. You could secure the back of the shelf to the wall for stability if you wanted to.