Knoxville, Tennessee · R-Stamp certified · On I-40 & I-75
Petroleum tank trailers.
Done to code.
Post Onsite is the East Tennessee specialty shop for petroleum tank trailers. R-Stamp certified welding, DOT tank testing, tank remounts, structural repair, compliance inspections — with the documentation fleet managers actually need at audit time.
Mon–Fri 7am–6pm · 24/7 emergency line for fleet customers
What the shop does
Specialty work, not everything for everyone.
Petroleum transport tanks, specifically. Refined products, heated petroleum, and a fast-growing book of propane tank trucks and propane (LPG) tankers. We don't do crude oil tanks. We don't do stainless. We don't do generic trailer work. The focus is what makes us good at what we do.
R-Stamp welding
Pressure-vessel-grade repair welding under National Board R-Stamp authorization. R-1 documentation on every job.
Learn more →Tank remounts
Mounting a sound tank onto a fresh chassis. Engineering review, structural welding, recertification, DOT-ready documentation.
Learn more →DOT tank testing
Annual external visual, periodic pressure, leak, upper coupler, and thickness testing on DOT 406, 407, 412, and MC-331 (propane) tanks.
Learn more →Barrel repair
Structural barrel repairs — bulkhead replacements, dents, fatigue cracks, baffles. In-shop where it should be.
Learn more →Compliance inspections
Pre-purchase, pre-lease, and pre-audit inspections. We give you the scope of work in writing so you can negotiate from facts.
Learn more →All services
See the full scope of work, tanks we specialize in, and what we explicitly don't do.
View services →Why Post Onsite
Documentation is the deliverable.
Most trailer shops can repair a tank. Few can produce the R-1 documentation, the test certifications, and the inspection records that hold up at terminal audits and DOT roadside checks. Compliance work isn't done until the paperwork is done — and that's where most shops fall apart.
We built the shop around that standard. Active R-Stamp authorization, real pressure-vessel discipline, and certifications kept current, paired with years of knowing what petroleum carriers actually need from a service partner. The repair and the paperwork that proves it, from one shop.
The parts room
The parts to finish the job, on hand.
Valves, fittings, gaskets, and tanker hardware in stock, backed by a deep parts inventory pooled across our sister shops. Less waiting on a part means your tanker is back in service sooner.
See parts & capabilitiesRemount Authority
Wondering if your tank is worth remounting? We tell you straight.
For fleets weighing remount vs. replace, we run an honest assessment — tank condition, structural read, recertification scope, total dollar figure. You get a real recommendation in days, not weeks, with the numbers documented so you can take it to your CFO.
Start a remount assessment →Tank trailer work to do?
Call the shop with what you've got — tank type, year, the work you think you need. We'll tell you whether it's in our wheelhouse and what the scope looks like.