This instructable shows how to build a very strong outdoor firewood storage/seasoning structure with a roof, from four IBC (Intermediate Bulk Container) cages, some metal pipes, corrugated steel sheets and various fittings.

Supplies

4 x IBC (Intermediate Bulk Container) cages, without the internal plastic bladders.

Galvanized steel pipes

2 x ~2.4m (depending on height of base, see instructions)
3 x ~3m (depending on amount of overhang you want on your roof)

2 x galvanized tee clamps: Outside Diameter "OD" thru 34mm, butt 27mm (or Nominal Bore "NB" 25 thru, 20 butt)

Galvanized strapping or sheet steel.

6 x Stainless steel pipe clips:

2 x 46-70mm
4 x 21-44mm

1 x ~3m Pine fence rail, 100mm x 50mm ("four by two") for roof

Optional Elements:

Pine fence rails 100mm x 50mm ("four by two"):

8 x 100mm long as "sleepers" for internal rails
2 x 241cm long for base
3 x 89cm long for base

6 x Concrete blocks ("cinder blocks") for base

N.B. Use google to convert to imperial measures, e.g. "241cm to inches"

Step 1: Build the Base

This is optional, but optimal. You could just put the cages on level ground and build from that. Or you could just have the concrete blocks or just the wood frame, but put them all together and you get extra height, extra air flow and all the components will last a bit longer. The height is valuable because you may not get to weeding around it as often as you should, so the grass/weeds will take longer to grow up into the structure and transfer moisture to the components and all your precious wood.

First, you need firm, level ground. If it's not level, the metal rails (pipes) won't sit right across the structure, since they are double wide. If it's not firm, the enormous weight of four cages' worth of wood will sink unevenly into the ground. Gravel would be optimal as it will inhibit grass growth, but I used old sheets of corrugated iron as ground cover, since I happened to have plenty lying around.

Of course you want to present the broad face of the wood to as much sun as possible, so the orientation of the footprint should reflect this.

Note that everything looks a bit grungy as I took the photos while I was DIS-assembling the structure, which had been in place for some years (and survived several storms intact).

First build the wooden sub-base from two 241cm wooden fence rails, with three 89cm rails nailed or screwed inside them. The middle one is just to add a bit of rigidity. One cage rests on all four sides and the other on three. You could add a fourth middle piece if you prefer to have both cages fully supported. If you were going to stack three high (which I've never tried) you probably would want the extra support.

Now you've got the outer dimensions in physical form, place the concrete blocks underneath such that the frame sits neatly flush with the outer edges.

Step 2: Placing the Cages

Place the first two cages on the base, with a small gap between them (first photo), and the drain scoops on the OUTSIDE - i.e. the cages are back-to-back. This is important, as the biggest gaps in the cage structure are above the drainage scoop. See bottom-middle of the second photo for what I mean by "drain scoop" - it's probably where the tap would be if the bladder were present. Believe me, sooner or later you'll need to put some large thing into the interior without taking the roof off and having those large gaps accessible on the outside helps a lot.

Lift the third and fourth cages onto the two base ones (needs two people), again making sure the drainage scoops are on the outside. At this point you will be able to tell if everything's aligned, as there should be a gap between the two towers right at the top similar in size to the bottom. That's what the gap's for, to allow a slight variance or settling while keeping each cage seated firmly in the one below rather than pushing against its neighbour.

Step 3: Adding the Roof

If you have help, you can first attach the upright (27mm diameter) poles to the side uprights of the cage closest to the front using the smaller hose clips (21-44mm), first putting something solid at the bottom like a brick or a piece of hard-wood (I sacrificed one of my spilts as shown in the second picture). Note that the height of this base support will affect the height of the top rail and therefore the angle of the roof, which should slop gently to the back to shed the rain. In my case, the split at the bottom came to the level of the top of the wooden sub-frame, and the pole resting on it was 2.4m

Then take one of the 34mm diameter poles and slide two "T" fittings over it, ready to slip on the uprights. Two people, each with his own ladder can do it this way, but it's a tricky maneuver to accomplish on your own, so you can instead assemble the cross bar and two uprights on the ground then "hang" it on the top and adjust/fix the uprights to the cages last. The cross pieces are greater diameter than the upright supports because the double-width span requires a stronger pipe to avoid sagging in the middle under its own weight.

Now place the long fence rail (four by two) on top at the back, sitting upright. Next place your corrugated iron sheet(s) on top - it depends what sizes you have; in my case it was three sheets of about 143cm x 85cm, placed with a slight overlap. If it's reused roofing, it'll have nail holes, so make sure these end up on the "peaks" and not the "valleys", otherwise the rain running down the valleys will stream onto your firewood.

Line it all up nicely, making sure there's pole extending beyond the iron, then place another 34mm pole over the front one with the iron between them, slip one of the larger hose clamps (46-70mm ) over the two ends and tighten, but not too much initially on the first one, as we want even pressure across the two. The result should be as per the third photo. Note that the pink landscape timber in that photo has no relevance and is not part of the construction - it was just a handy place to store an awkwardly long item.

Lastly, you want to secure the back edge, and for this I prefer stainless pre-drilled stripping (fourth photo), but by the time I got to doing the final four-cage setup I had none left so I cut a piece out of a piece of thin galvanized steel plate (last photo). You're going to clamp the rear of the roofing sheets in the same way, but between pipe and wood, using a strip of metal screwed in to the wood, instead of a hose clamp. My technique for getting a mild degree of clamping tension was to fix the first end just with hand-grip pressure, then on the opposite end use a G-clamp as shown in the fourth picture to free my hands to hold/screw the strap on while maintaining pressure. Don't go crazy with the pressure as we don't want the pipe to bow upwards - the goal is even pressure along the entire contact with the roofing sheets.

If you have any gaps that rattle in the wind, you can shim them with whatever wooden or rubber wedges you happen to have. I actually used small/halved sections of plastic irrigation hose, which was handy as they can be flexed to fit over the pipe then slid/wedged into the gap. I also used these to shim the internal rails in the last step.

Step 4: Internal Rails for Stacking Wood

This step is optional. You can just chuck the wood in, and that's what I did with all the "uglies" - i.e. the irregular pieces that won't stack. But if you have the time and inclination, stacking the stackable wood nicely will season it a lot better, as the moisture exits the END of the split, so you ideally want that surface exposed to the sun and wind as much as possible.

So, once your external structure/roof is set up, you can turn your attention to the internal.

If you think of a railway line, it has wooden sleepers and metal rails, and that's the analogy for how I do mine. The sleepers are 100cm long and can be pieces of "four by two" (100x50mm). I also happened to have some unused "roundwood" which is sometimes used as edging on gravel driveways to separate them from the lawn. I used a combination of the two, since they were equivalent. You can see this in the upper right cage of the main photo at the top.

You place these "sleepers" two per cage across the short width - i.e. North/South looking at the structure from the front.

Then you place galvanized pipes East/West resting on the sleepers and spanning the two cages, and your firewood stacks North/South on those pipes. When I dismantled the structure most of my firewood was used up, but I have an older photo (pic 1**) which shows the final result nicely: There's odd-shaped splits in the bottom cage (i.e. not stacked), dark hardwood stacked in the lower part of the top cage, and lighter pine softwood stacked above it. The second photo shows the front stacked row, seen from behind on a sunny day. This to my mind is optimal: plenty of gaps for airflow and the end of each split getting maximum sun.

I do the sleeper/rail method because I happened to have many pipes that could span the two cage widths - if you have instead many long wooden rails, go ahead and use them East/West without worrying about sleepers and stack your wood directly on them. The essential point is to have the load-bearing points on the outer ridges of the metal floor-pan of the cage, as this is the strongest part. The lattice work of the cage itself is not strong enough to bear significant weight as it's just lightly spot-welded. However, as you can see in the third photo, it's a handy covered space to store your spare long items.

Behind the front row you can have a second one, either for fresh wood you don't intend to use this season, or for already seasoned wood that doesn't need the sun. Of course, being in the open air and sheltered from the rain it'll still season, but more slowly.

** Addendum: The first photo in this section shows an earlier version that had rails but no "sleepers", but was not ideal for several reasons: The metal on metal contact (could damage the galvanized surfaces); the small airflow/cleaning gap beneath the wood; the wider unsupported spans; the difficultly of getting exact rail to metal contact on all touch points compared to the "give" that wood provides.

Step 5: Additional Advice

If you go for the 'wooden sleeper/metal rails' method, you may encounter two problems:

The rails (i.e. pipes) tend to move around maddeningly as you're stacking
The rails may not have perfect contact with the sleepers, and therefore not ideal weight distribution.

For keeping the alignment of the rails as you add wood and before the weight is sufficient to keep them in place, you can fix them to the cage with cable ties as shown in the first photo above. If on the other hand you want to locate the pipe/rail not where the cage upright is, you can get two thin pieces of wood and drill two holes at the desired spacing, and slip them over the ends of the pipes as shown in the second photo. Then once enough weight is on the rails to lock them in place, you can reuse the spacers on the next pair of rails to be loaded.

For making sure the rails (pipes) contact the sleepers at every intersection, you can shim with short sections of irrigation pipe with an internal diameter approximately the same as the rails outer diameter, which cut in short lengths and split lengthwise then stretched to clip over the pipe and slid to where the gap is. They can even be doubled to make a thicker shim. Or you can just use little shims of some other material.If you don't bother shimming significant gaps, the pipe will tend to get bent over time.

Step 6: Bonus - Indoor Drying Rack

This is a strong rack built around a wood burner, for "finishing" seasoned or rain-wet firewood.

I have no dimensions for this: It will depend entirely on the size of your wood burner. The components are:

Several 27mm OD (Outside Diameter) galvanized steel pipes.
Two mesh shelves (fireproof!)
Assorted tee clamp or MasterKlamp (allen key) pipe fittings & feet
Underfoot pads

For the sides, I happened to have two light-duty scaffolding frames, but you can get the same result with two upright and two cross-piece pipes.

The feet and bottom front fittings are MasterKlamp brand, because that's what I happened to have, but you can substitute whatever brand type you can source locally. The first photo doesn't show with the lower shelf or flue guard, which you can see in the third and fourth photos. The flue guard is just a piece or wire mesh bent into a curve then attached to the shelves by cutting the mesh in the appropriate places and bending the free bit into little "hooks". It's intended to prevent wood touching or falling against the flue.

The two shelves are just some wire rack pieces of unknown origin. Maybe from some sort of pet cage. I cut out a space for the flue to pass through.

The top shelf support is ideal: several small diameter pipes laid under to support the shelf. They are just held in place by the weight of wood, so lay the first few pieces of firewood gingerly, or better yet, fix them in place somehow. The second photo shows how I used a tee-fitting to grab the shelf at each corner and stop it rolling on the supports. You could probably come up with something more elegant, but I happened to have spare tee clamps.

The second shelf was adequate but less than ideal: Although it never failed, I tended to put fewer/lighter pieces on there because I was using flat steel strips as supports, which I feared would bow under weight. If I had kept the construction another year I would have done pipe supports like the top shelf. For the height of the lower shelf, just judge for yourself a decent gap above the top of the wood burner. I went with 90cm from the top of the feet.

The diagonal at the back is absolutely CRUCIAL. Do not omit this step; it gives the structure much of its strength.

If your hearth is stone, as this one was, put some pads under the feet. I used, bottom to top:

Squares of cardboard
Squares of thin plywood
Squares of flooring vinyl

Maybe overkill, but I really wanted to avoid damaging the landlord's hearth, and this arrangement worked beautifully, leaving no trace despite significant weight of hardwood loaded on to this structure. The bottom cardboard at first seemed "welded" to the stone, but a teaspoon of water left on over night and they lifted off cleanly.

Final Thoughts - Critters

If you cut and split your own firewood and get it off the ground immediately, you probably won't have any problems with cockroaches or other nasties (remove the bark if possible, or keep the barked pieces separate). However, if your firewood has been on the ground for a while at any stage it may pick up some unwanted hitch-hikers. This is something you should be aware of if you will store it inside for an extended period, such as using this wood burner rack.

You can put some sticky traps ("roach motel" type) in your outdoor racks, in some sort of waterproof enclosure open at both ends. (Even if your storage has a roof, you need to protect them from driving rain, condensation, etc.) Make sure not to box them in with firewood as you want to inspect them from time to time to see if you've got a problem.

If there are signs of an infestation, you have a few options:

Bring the seasoned splits into the house in a container with a lid and burn immediately.
Ramp up the trapping in the rack until no more catch (could be expensive).
Half fill a barrel with water and dunk the seasoned splits, pushing them down briskly with a pipe or broom handle to get the water in every crack, and see if anything comes out. Then put in the sun away from vegetation to surface-dry, then finish on an internal rack close to the wood burner. The seasoned wood won't absorb enough water in a brief dunking to be a problem.

I would not recommend using any chemical spray on the wood as this may be released when burned, and damage your wood burner.