A demolition contractor working a site half a mile from us came in during March with a specific problem. They needed water on a spray boom, they needed to move it four times a day with a forklift, and every commercially available unit they had priced was either too expensive to risk on a demolition site or too delicate to survive one.
This is the simplest thing our shop builds and the one that most often gets overbuilt by people who have never watched a demolition crew handle equipment.
Specification, by subtraction
The design question here is not what to add. It is what to leave out, because every component is a thing that can be broken by a distracted operator with a forklift.
| Component | Included | Reasoning |
|---|---|---|
| Grade C 275-gallon tote | Yes | Cheapest suitable; will be abused; we buy it back |
| Forkliftable steel skid | Yes | Takes the abuse instead of the cage |
| Engine-driven pump, 2 in | Yes | No site power, no extension leads to run over |
| Strainer ahead of pump | Yes | Site water carries grit; this is the failure point |
| Boom spray bar, 8 ft | Yes | The actual job |
| Pressure gauge | No | Breaks in week one, tells you nothing you need |
| Flow meter | No | As above |
| Electric controls | No | Water, dust and a site — no |
| Level sight tube | No | Translucent bottle plus a torch does the same job |
| Lockable cabinet | No | Adds cost; the pump is the theft risk and it is bolted |
The strainer is the whole build
If you take one thing from this: site water is not clean water. It is whatever came out of a hydrant, plus whatever was in the container, plus whatever fell in while the lid was off, plus grit from the last fill.
An engine-driven pump with no strainer on a demolition site fails within a fortnight, usually by scoring the impeller or jamming a check valve. It is always the pump that gets blamed and it is always the missing strainer.
We fit a 40-mesh Y-strainer with a blowdown valve between the tote outlet and the pump inlet. It costs $48 and it is the difference between a season and two weeks.
The build
- Skid first: 3-inch channel, 4-way fork entry, 8-inch clearance under the tote, lifting eyes at four corners because somebody will crane it eventually.
- Tote strapped at the cage top rail, not over the bottle. Two ratchet straps plus a bolted retainer at the base.
- Outlet to strainer to pump on the shortest possible run. Every foot of hose is a foot to be run over.
- Pump bolted through the skid, guarded on the fuel tank side, with the pull start facing outward.
- Discharge to an 8-foot boom on a hinge, so it folds flat for transport and is not the first thing to catch a doorway.
- Fill via a 3-inch camlock on the lid, because hydrant fills are fast and a 6-inch opening with a hose in it is how grit gets in.
- Everything painted the same colour so a missing part is visible from across a site.
Cost
| Item | Cost |
|---|---|
| Grade C 275-gallon tote | $78 |
| Steel skid, fabricated | $385 |
| Engine-driven pump, 2 in | $340 |
| Y-strainer, 40 mesh, with blowdown | $48 |
| Boom spray bar, nozzles, hinge | $168 |
| Hose, camlocks, fittings, straps | $94 |
| Paint and labour | $137 |
| Total | $1,250 |
The nearest catalogue equivalent they had priced was $4,600. Ours will not last as long — we would expect one to three demolition seasons before the tote is finished and probably five before the skid is — but it costs a quarter and the expensive parts are all unbolt-and-reuse.
End of life, which matters here
When the tote gives up, the pump, strainer, boom and skid come off and go onto a new one for about $90 of consumables. The dead tote comes back to us, gets granulated, and its cage goes to the mill.
That is the real argument for building site equipment on a container rather than buying a moulded unit. A cracked purpose-built tank is a single object that is finished. A cracked tote on a skid is a $78 component swap.