Tank coating bids: build the scope before pricing the lining

What belongs in a storage tank coating bid?

A usable tank coating bid identifies what gets coated, how the surface becomes ready, what system goes on it, and how the owner accepts the finished work. Put tank identifiers and drawing revisions on that scope. A price attached only to a capacity and the words blast and paint leaves too many decisions until after mobilization.

Split the work into interior lining, exterior coating, and repairs. Add access, containment, cleaning, inspection, and restoration as identifiable costs even when the bid form requires one total. The owner can then compare proposals against the same work, and your foreman can see what the estimate actually bought.

Portsmouth's water tank rehabilitation project illustrates the distinction. Its August 19, 2026 update describes spot repairs plus full exterior coating at Spinney Road, full interior and exterior work at Newington Booster, and spot work at Lafayette [1]. Those are different scopes within one program. The published project shows scope separation. Check current solicitations for available work and build unit prices from the measured scope.

Bid scope worksheet

Complete this worksheet with the owner or engineer before committing to a firm price. Give each answer a document reference, responsible party, and status: confirmed, allowance, or unresolved. List missing answers for clarification.

For a public solicitation, submit questions through its stated process and carry the written response or addendum into the estimate. If the bid form prohibits qualifications, resolve the gap before bidding or make a bid-or-pass decision. Do not rely on an exclusion that the purchasing rules will not accept.

What should you verify at the tank before bidding?

Start with an authorized external survey and the owner's inspection packet. Match the nameplate and tank number to the drawings. Check access roads, gates, laydown, hose routes, power, water, nearby equipment, and where spent abrasive can be contained and loaded. Record measurements and permitted photographs with locations. Identify anything you could not inspect.

Measure surfaces rather than converting storage gallons into a coating area. Shells, roofs, bottoms, internal framing, columns, ladders, and nozzle details create different work. Separate inaccessible areas and detail work from broad open surfaces. State whether your takeoff uses gross area, deducts openings, or includes both faces of internal members.

An exterior photograph cannot establish interior lining condition, stored contents, steel thickness, or buying intent. Do not enter during a sales survey without the applicable entry arrangements. If the interior cannot be made available, request a qualified condition assessment or price a defined investigation before fixing the rehabilitation scope.

Keep coating assessment separate from structural acceptance. EPA's bulk oil storage guidance distinguishes visual inspection, testing, and evaluation of fitness for continued service [6]. That guidance concerns covered oil storage, not every water tank. Name who evaluates the steel and releases repairs before coating starts.

How do you define surface preparation and the lining system?

Specify the preparation grade, surface profile, contamination checks, weld and edge treatment, and inspection release. Tnemec's Series 21 instructions distinguish blast cleanliness from profile and require a clean, dry surface under stated environmental conditions [2]. Record each requirement separately; a clean-looking surface does not establish the profile or application conditions.

Request the existing coating's identity, adhesion assessment where relevant, and compatibility basis before pricing an overcoat. For full removal, include cleaning, abrasive handling, dust control, spent material collection, and the agreed disposal route. For spot repairs, define the mapped repair area, preparation method, feathering, overlap, and measurement rule. An undefined percentage of repairs is difficult to reconcile later.

Build the coating schedule by surface and service: product, primer where required, stripe coats, full coats, per-coat and total dry film thickness, recoat limits, and immersion cure. Obtain manufacturer confirmation for the actual contents, temperature, substrate, and existing system. For potable service, request the certification and application conditions required by the specification, including the exact product listing.

Tnemec's Series 21 data sheet illustrates why generic epoxy is insufficient. It distinguishes immersion preparation from atmospheric preparation and identifies separate recoat and potable-water immersion times [2]. It is a product example, not a selection for every tank. Resolve conflicts between the project specification and product instructions in writing before procurement.

What access and confined-space work must the price cover?

Price access for preparation, application, inspection, repair, and removal. Measure manways and determine how equipment and materials reach each surface. Check whether staging blocks inspection or rescue routes. Assign scaffold design, erection, inspection, modifications, and dismantling. Include ground protection and interference with operating facilities in the site plan.

Have the responsible safety lead determine the applicable work classification and entry requirements. Construction confined-space requirements appear in 29 CFR 1926 Subpart AA; general-industry permit-space requirements appear in 1910.146. North Carolina's labor department publishes the relevant provisions [3, 4]. Being inside an existing tank does not by itself decide which work standard applies.

Carry the resources identified by that assessment: isolation coordination, atmospheric testing and monitoring, ventilation, suitable lighting, communications, protective equipment, attendants, and the selected rescue arrangements. Construction requirements include evaluating rescue capability and access [3]. Obtain a scope and price from the rescue provider. A telephone number alone does not describe the service your crew needs.

Confirm who drains, cleans, isolates, and releases the vessel, then document the contractor's verification duties. An owner's clean-tank handoff does not replace the employer's hazard evaluation. Keep coating, blasting, and hot-work activities coordinated so one operation does not introduce hazards into another crew's space.

Who owns hazardous-coating and waste costs?

Request representative existing-coating and residue information before choosing a removal method or disposal allowance. Record who commissions sampling, who interprets the results, and who confirms the receiving facility's acceptance. Separate worker-exposure assessment from waste characterization; they answer different questions. Neither can be settled by the color or apparent age of the paint.

The construction lead requirements include exposure assessment and protective measures for covered work; North Carolina's published requirements identify those duties [5]. Allow for the controls, hygiene facilities, monitoring, training, and specialist services that the actual assessment requires. This worksheet does not set exposure limits or choose a respirator.

Define responsibility for wash water, sludge, spent abrasive, coating debris, packaging, transport, and disposal records. State the quantity and classification behind each allowance. If characterization is missing, obtain it or use an owner-approved mechanism for that uncertainty. A general contingency should not conceal an unbounded hazardous-waste obligation.

How long must the tank stay out of service?

Build the outage from operational release through accepted restoration. Include draining, cleaning, isolation, access installation, preparation, steel inspection and repairs, application, cure, testing, access removal, and the owner's return-to-service steps. Identify tasks that can overlap and tasks that require a signed hold-point release. Labor shifts and equipment rental days are different quantities.

Cure is a condition-dependent activity. Tnemec's Series 21 sheet lists seven days to potable-water immersion at 75 degrees F and ten days at 55 degrees F, with other conditions affecting cure [2]. Those values apply to that product's stated conditions. Use the selected system's current instructions and actual surface-temperature record for the job.

Assign who supplies and pays for ventilation, heating, dehumidification, power, and condition checks through cure. Define the response to a power loss, weather interruption, or missed recoat window. Do not promise a return date based only on the number of spraying shifts.

For potable tanks, identify the specified disinfection, sampling, and release responsibilities separately from coating acceptance. AWWA's current list identifies D102-24 for steel water-tank coating and C652-25 for storage-facility disinfection [7]. Confirm the contract's editions and utility requirements; the public titles alone do not supply the acceptance procedure.

Which inspection hold points belong in the bid?

Give each hold point an acceptance document, responsible inspector, notice period, and release record. Ask whether the inspector is owner supplied or contractor supplied, and who pays for standby and repeat visits. Price access for the inspector while the relevant surface is reachable.

Use the following checklist to assign inspection and release duties. The project specification and selected coating instructions set the methods, frequency, thresholds, and repair process. Price specified thickness and discontinuity testing. Confirm the system's test method and voltage before including electrical holiday testing.

Worked example: price a defined interior lining scope

A typical private potable-water tank has a 40-foot inside diameter, a 20-foot cylindrical shell, a flat bottom, and a conical roof rising 5 feet. The scope covers all interior steel, including the roof underside. Using pi times diameter times height gives 2,513 square feet of shell. The bottom is 1,257 square feet; the conical roof is pi times 20 times the square root of 425, or 1,295 square feet. Add 135 square feet of separately measured internal details. Rounded areas total 5,200 square feet, with no deductions for small openings.

The owner supplies a qualified condition assessment and accepted coating and residue characterization. The base scope requires no structural repairs or hazardous-waste handling. It includes full old-lining removal, specified near-white blast preparation, routine weld dressing, stripe work, and an approved two-coat immersion system at a modeled total 20 mils dry film thickness. Manufacturer approval of the service, profile, thickness, and seven-day immersion cure at maintained 75 degrees F surface temperature is an explicit example input.

The case uses a Tuesday start with nine eight-hour weekday production shifts in a thirteen-calendar-day work block, seven full calendar days reserved for cure, then a final weekday shift for acceptance support, access removal, and cleanup on day 21. This plan does not credit early cure during the work block and includes no final repair that restarts cure. Access and conditioning rentals cover 21 calendar days. The owner separately allows two days before that block for draining, cleaning, and isolation, and two afterward for disinfection, sampling, filling, and release. The preliminary outage allowance is 25 days, subject to actual acceptance and laboratory scheduling.

The case uses three production workers, including a working foreman, at $70 per person-hour and one dedicated attendant at $60 per person-hour during all ten shifts. Rates include wages, payroll burden, and benefits. Production hours cover setup, preparation, application, routine repairs, and removal. The sample rescue quote covers the approved entry windows; the separate condition-watch allowance covers 20 hours during cure. Set staffing and rescue coverage from the entry assessment for the actual job.

Lump sums include applicable material taxes, freight, and subcontract mobilization. Materials include stripe coating, normal application loss, and routine defect repair. The owner provides the agreed utilities and pays any permit fees. Local travel is included in mobilization, no lodging or overtime, no performance bond, and no special wage schedule. Company overhead and profit come from gross margin. Exterior work, structural repairs, hazardous waste, and the owner's restoration work are excluded; any tax on the contract sale is outside the price shown.

What happens when repairs or delays change the job?

Anvilfield research puts the amount above the budgeted cost basis at $22,750, about 25.01% of revenue. That amount pays overhead and profit; it is not net profit. Dividing $90,950 by 5,200 square feet gives about $17.49 per square foot. That rate covers the defined package; rebuild the scope before pricing a different tank.

Now add three extra cure days after access was scheduled for removal. Additional daily direct costs are $150 for access, $350 for conditioning equipment, and two monitoring hours at $70, with no other added costs. That is $640 per day, or $1,920. Reapplying the same 10% reserve to $63,920 gives a $70,312 cost basis. The unchanged price leaves about 22.69% margin; preserving 25% requires $93,749.33 before rounding.

The arithmetic does not establish a right to extra payment. State how weather, owner delays, changed access, and additional cure requirements are handled under the actual contract. For newly exposed steel defects, stop the affected work, record the location and quantity, obtain the qualified repair decision, and secure the required authorization. Define any repair unit price by the approved repair detail, measurement method, inspection, and schedule effect.

What to document before submitting the bid

Keep the takeoff, inspection reports, photographs, specification and addendum register, product instructions, subcontract quotations, schedule, responsibility worksheet, and estimate together under the tank ID. Mark the date and revision on each. The estimator's package should let the project manager reproduce the basis without another site visit.

A weak note says: Repaint tank, includes prep. A stronger account note says: Tank W1 interior only, 5,200 square feet gross including roof underside and details; full removal; owner supplies drained and isolated vessel; approved system and inspection plan attached; structural repairs excluded pending engineer direction. Add who performs cleaning, testing, waste handling, and restoration so every exclusion has an assigned owner.

Before submission, reconcile the internal estimate with the required bid form. Confirm alternate prices, unit-price quantities, addenda, qualifications, bonds, required visits, completion dates, and payment terms from that solicitation. Carry only exclusions and allowances the form permits. Save the submitted version, then hand the same scope to operations after award.

Common mistakes

Pricing from storage capacity hides the actual surfaces and access burden. Combining interior and exterior work hides different preparation and acceptance requirements. Resolve both with a surface schedule and separate estimate lines.

Treating every paid hour as productive blasting or spraying hides entry support, staging, cleanup, and records. Count those hours explicitly. Carry rental days through inspection and cure, including days without application labor.

Using a contingency to cover unidentified waste or unlimited steel repairs leaves the bid boundary undefined. Investigate, use a permitted allowance with a measurement rule, or obtain a defined alternate. Compare included tasks and owner responsibilities before comparing totals.

Field bid checklist

Finding public tank rehabilitation work

Search for the work package your crew can deliver: tank rehabilitation, interior lining, exterior repainting, or reservoir coating. Read the owner-issued documents before treating a notice as suitable. Record the agency, tank IDs, procurement stage, site-visit requirements, question deadline, bid deadline, qualifications, and outage window.

PorchRocket Bid Control has a painting-specific destination for public painting work [8]. Use it to start the search, then verify the current solicitation and addenda with the issuing agency. A project announcement or award record can identify an owner and work type, but does not establish an open bidding opportunity.

Bring a candidate into this worksheet before investing in a detailed takeoff. Pass or arrange the required specialist support when access, hazardous-material controls, structural repairs, or the outage exceed your capacity. Use the related Anvilfield guides for coating execution, confined-space planning, inspection records, and scope changes once the bid boundary is established.

Standards and references

Sources checked November 4, 2026. Portsmouth's project update is dated August 19, 2026; EPA's inspection fact sheet is dated August 2013; the Tnemec data sheet is dated November 14, 2024. AWWA's list identifies D102-24 for coating and C652-25 for disinfection. Confirm the editions required by the contract before pricing acceptance work.

The full AWWA and AMPP standard texts and an independent NSF product listing were not reviewed. Obtain the specified editions, current certification evidence, selected product instructions, and site requirements before setting acceptance values. State labor references below reproduce relevant federal requirements and do not determine the jurisdiction or work classification for your tank.

Units and terms

Dry film thickness

DFT: coating thickness after drying, expressed here in mils. One mil is one thousandth of an inch.

Hold point

A defined stage where the specified inspection and release must occur before the next work proceeds.

Person-hour

One person's paid time for one hour. Count production, support, inspection, and monitoring time separately.

Gross margin

Revenue minus the stated cost basis, divided by revenue. The example includes contingency in cost and leaves overhead to be paid from margin.

Methodology

Counts, prices, work rates, schedules and outcomes in typical cases are inputs to the Anvilfield research model. Calculations use the stated scope, formulas, cost inclusions and exclusions. Cited public records and technical documents support their attributed facts. Named case records, dates and outcomes are scenario inputs; cited public records retain their source attribution.

Related tools

FAQ

People also ask

• What is a tank lining?
• Why is surface prep important for coatings?
• What is a permit-required confined space?
• What is the difference between a UST and an AST?
• What is an inspection and test plan?