Wheel loaders, dump trucks, and excavators need a place to get clean without contaminating the storm system. We build wash bays with engineered slab thickness, slope that moves water to trench drains, and oil-water separators that meet environmental discharge rules. Boston Concrete handles the whole system from excavation through separator integration and testing.
When a loader or dump truck gets washed on your property, the runoff carries oil, sediment, and detergent. That water cannot go straight to the storm drain. Environmental rules require it to pass through an oil-water separator first, which means the concrete slab has to be engineered to move all wash water toward a drain system that feeds the separator.
We size the slab for the heaviest equipment in your fleet, slope the entire bay surface toward trench drains positioned for maximum capture, integrate the separator into the drainage path, and apply chemical-resistant finishes if your wash process uses degreasers or alkaline cleaners. The result is a bay that handles daily washing while staying compliant with discharge limits.
We measure the bay footprint, identify the heaviest equipment that will use it, determine where trench drains and the separator will sit, and confirm the discharge connection point. All of this gets engineered as one integrated system before any excavation.
Excavate and prepare subgrade
The bay area is excavated to the correct depth, subgrade is compacted to specification, gravel base is placed, and any plumbing for drains and separator lines is routed before concrete forms are set.
Form, reinforce, and pour
Forms are positioned with the engineered slope in every direction toward the trench drains. Rebar is placed for the equipment loads. The concrete is poured, finished with a broom texture for foot grip during washing, and the slope is verified with water flow tests before the slab cures.
Install drains and separator
After cure, trench drain grates are installed, the oil-water separator is connected to the discharge line, and the entire system is tested with water to confirm proper flow and separator function before handoff.
The critical detail
Why Slope Cannot Be Fixed After Cure
A wash bay without proper slope is just a concrete pad that collects water. Every part of the slab must slope toward a drain, and that slope has to be consistent so water does not pool in corners or low spots. We verify slope during the pour using a level and water flow tests, not after the concrete hardens. If slope is wrong, the only fix is tear-out and replacement, which is why we get it right the first time.
The slope verification process is part of our heavy equipment concrete standard. Coordinate with your industrial concrete contractor on the full site plan, including how the wash bay connects to other equipment pads and the separator discharge.
Trench drains, oil-water separators, slope verification and storm-water compliance.
Storm-water regulations require hydrocarbons to be removed before wash water enters the storm system. Oil-water separators are the engineered solution; without them, the wash bay's discharge violates discharge limits and can trigger fines or shutdowns.
During the pour with a level and a water flow test, then again after cure. Every direction across the bay must carry water to a trench drain; pooling anywhere means the slope is wrong and needs correction before the slab cures.
Sometimes, if it can be sloped (often it cannot), drained (usually needs new trenches cut), and routed to a separator (almost always new work). The economics often favor a purpose-built bay; we will assess case-by-case.
Yes if degreasers or harsh detergents are part of the wash cycle. Standard concrete surface degrades under repeated alkaline or solvent exposure; chemical-resistant treatment extends slab life dramatically.
Several weeks from excavation through cure and separator install. The full schedule is in the quote, including time for the environmental discharge connection if regulatory review is required.
New wash bay with proper slope to trench drains and the oil-water separator we needed for compliance. Discharge passes regulatory inspection, equipment gets washed faster, no more puddles in corners.
Z. K5
Fleet Manager, Boston
★★★★★
They engineered for our wheel loaders and dump trucks, the heaviest stuff we run. Slab has held under daily traffic, drainage works through every wash. Right tool for the actual fleet.
Y. K5
Operations Director, Cambridge
★★★★★
Wash bay with chemical-resistant surface for the degreaser we use. Three years of operation, no surface degradation, separator processes hydrocarbon properly. Compliance side covered.
Q. K5
Mining Operations, Somerville
★★★★★
They tested the slope with water before signing off. Pooled in one corner; they corrected it before cure. Final result drains perfectly. Real install discipline.
X. K5
Construction Yard Manager, Quincy
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Describe your equipment fleet, wash chemistry, and where the discharge will connect. We will engineer the bay and send a written quote within one business day.
