Bid or no-bid: when the roofing tender is actually a whole-building reclad

Steve Parker
Jul 4
8 min read

Updated: Jul 9

A roofing subcontractor was invited to price a public-sector remediation tender that read, on the cover, like a roofing job. The pack described a whole-building reclad head contract with 20-plus sublet trades, a 10-year warranty deed, and roofing at barely a fifth of the value. Reading the whole pack before pricing a line of it turned a business-threatening bid into a $30–45k subcontract opportunity.

By Steve Parker · Trueworks · NZ construction estimation · 7 min

What you'll learn in this case study

How a "roofing tender" turned out to be a head contract with 20-plus sublet trades and a single-point 10-year weathertightness warranty deed
The five pack items — role, warranty tail, retentions, insurance, unknowns — that decide bid or no-bid before any rate gets written
How two scenario subcontract prices kept our client in the job without carrying the building

Quick answer: A roofing subcontractor was invited onto a closed, secondary-selection tender for weathertightness remediation of a school hall block owned by a government property client. The invitation read like a roofing package. The pack said otherwise: a whole-building reclad head contract in which roofing was only about 15–25 percent of the value — roughly 65 m² of new lean-to roof plus flashings and spouting, with the main hall roof explicitly unchanged. Buried in the conditions were principal-contractor health-and-safety duties, 20-plus sublet trades to manage, a single-point 10-year weathertightness warranty deed, retentions held to the final completion certificate, five-figure aggregate insurance excesses, a 6–8 week payment lag, heavy provisional sums for timber decay, and an unassessed asbestos risk on a 1990s fibre-cement reclad. We recommended declining the head-contract role and instead offering a roofing and flashing subcontract price — about $30–45k across two scaffold scenarios — to whichever builder wins.

The tender pack

A roofing subcontractor — long-run and membrane work, mostly residential and light-commercial — was invited to price an RFQ from a government property client. Closed tender, secondary selection: a shortlist of invited firms rather than an open listing. The subject was weathertightness remediation of a school hall block, and the invitation framed it as a roofing-led envelope fix.

The pack came to us with a simple question: what should we price this at? After a first pass, our answer was a different question: are you sure you are the contractor this pack is describing?

The drawings and specification described a whole-building reclad: existing fibre-cement cladding stripped, structural timber inspected and replaced as required, a new cavity-based cladding system, joinery flashings redone — and roughly 65 m² of new lean-to roof with flashings and spouting. The main hall roof, where a roofer's eye goes first, was explicitly unchanged. Measured across the whole job, roofing was around 15–25 percent of the value.

The rest belonged to other trades: demolition, carpentry, cladding, joinery, scaffolding, painting, services — 20-plus sublet trades, all engaged and managed by the head contractor. The invitation was to be that head contractor.

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What we found

Reading past the drawings into the conditions, the pack loaded the head contractor with obligations that have nothing to do with installing roofs and everything to do with carrying a building.

Principal-contractor health-and-safety duties. Inductions, trade coordination, exclusion zones around an operating school, overlapping duties across 20-plus other businesses. A different order of exposure from running your own crew on someone else's scaffold.

A single-point 10-year weathertightness warranty deed. One deed, signed by the head contractor, warranting the performance of the whole envelope — cladding, junctions, joinery, roof — for a decade. Our client would have been warranting the 75–85 percent of the work performed by trades it does not control.

Retentions held until the final completion certificate. Not practical completion — final completion, which can sit a long way beyond handover.

Insurance excesses borne by the contractor. Multiple policies, each with its own excess — a five-figure aggregate exposure.

A 6–8 week payment lag. The head contractor funds wages, materials, and every subtrade across that gap.

Heavy provisional sums. The extent of timber decay was unknown until the cladding came off. Large slices of the contract value were provisional — priced blind and resolved later.

Asbestos not yet assessed. A 1990s fibre-cement reclad and no asbestos survey in the pack. Whoever signed as head contractor would inherit the management of that unknown.

And the technical traps mirrored residential work: a lean-to at about 3 degrees, below most long-run profile minimums, and a marine exposure zone driving the fastener and coating spec upward.

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The clauses and code points that settled the decision

The pitch. About 3 degrees sits at or below the minimum pitch most trapezoidal and corrugate long-run profiles carry under the metal roofing code of practice. Add laps and penetrations and the honest answer is membrane or standing-seam tray — a different rate per m², substrate, and crew from the one a long-run price assumes.

The exposure zone. Marine exposure lifts the durability requirements under clause B2 of the Building Code: coating class up, stainless or class-4-plus fasteners, marine-grade flashings.

The warranty deed against the trade. A roofing warranty is a promise about your own workmanship and materials. The deed in this pack was a promise about everyone's work, for 10 years, backed by our client's balance sheet.

The retention and payment mechanics. Retentions to the final completion certificate, a 6–8 week payment lag, and six-figure turnover flowing through a business built for subcontract-scale working capital. The arithmetic said the job could be won and still sink the winner.

The answer was no-bid — but not a silent one. We drafted a courteous decline of the head-contract role and attached the thing our client is genuinely qualified to warrant: a roofing and flashing subcontract offer, priced two ways — with the client's own scaffold and edge protection, and with the head contractor's scaffold provided. Both scenarios landed inside a band of roughly $30–45k, and the letter invited the client to pass the offer to whichever builder won.

That is the move worth copying: declining the building while staying in the job.

What it costs when it's caught late

| Stage caught | Cost range | Why | |---|---|---| | Before pricing — a day reading the pack | About $500–1,000 of time | The read reveals the role; the decline-and-offer letter costs little more | | After pricing, before submission | About $3,000–8,000 | Estimating 20-plus trades is a week-plus of unrecoverable effort either way | | After award, at opening-up | About $50,000–150,000 of exposure | Provisional sums for decay and unassessed asbestos convert into real scope on your contract | | At practical completion | About $15,000–40,000 held | Retentions run to the final completion certificate, not to handover | | Years 2–10, warranty claim | Six figures | The single-point weathertightness deed covers trades you never controlled |

The five-point bid/no-bid checklist we now run

Confirm the role. Find the words "head contractor" or "principal contractor" in the conditions. If the pack asks you to manage other trades, you are not pricing your trade — you are pricing a business you may not have.
Find the warranty tail. Search the pack for warranty deeds and durability obligations: who signs, what it covers, how long. A 10-year single-point deed on multi-trade work is a decade of balance-sheet exposure.
Find the retentions and payment terms. Retention percentage, release trigger (practical versus final completion), claim-to-payment cycle. Model the working capital before you model the margin.
Count the unknowns. Provisional sums, unassessed asbestos, undiscovered decay. Every unknown either carries a contingency figure in your price or a qualification in your letter — silence carries it for nothing.
Price the scenario, not just the job. If the head-contract role is wrong for you, offer the subcontract package to whoever wins, and price the variables — scaffold, access, staging — as separate scenarios so the offer survives any winner's methodology.

FAQ — bid or no-bid on head-contract invitations

Q1: How do I tell whether a tender invitation is for a head contract or a subcontract? Ignore the invitation email and read the conditions. Who engages the other trades, who holds the site health-and-safety duties, who signs any warranty deed? If those answers are "you", it is a head contract, however trade-specific the invitation sounded.

Q2: Is it damaging to decline a closed-tender invitation? Handled well, no. Clients shortlist firms they want to work with; a prompt, reasoned decline that offers a subcontract price instead reads as competence, not reluctance. What damages a relationship is winning a role you cannot deliver.

Q3: What is a single-point weathertightness warranty deed? A deed in which one party — usually the head contractor — warrants the weathertightness performance of the whole building envelope for a fixed term, often 10 years. Signing one means standing behind every trade's envelope work, not just your own.

Q4: Could we have qualified our way out of the burdens instead of declining? Only partly. Qualifications can trim scope and shift specific risks, but a public-sector client is unlikely to accept a head-contract tender that strikes out the health-and-safety role, the warranty deed, and the retention regime — those are the reasons the head contract exists. When the qualifications would have to delete the role itself, decline.

Q5: How do you price a subcontract offer without knowing who wins the head contract? By pricing the variables as scenarios. Scaffold, access, and staging swing with the winner's methodology, so we priced with-scaffold and without-scaffold as separate figures inside the $30–45k band. Any winning builder can slot the right scenario into their buy-out.

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About Trueworks

Trueworks is built by Steve Parker — 20 years on the analytical side of NZ construction. Variation reviews, contract advisory, programme review, and document-heavy estimation work. Trueworks is the productisation of that practice for NZ trades and builders: the same defensible analysis, at a price and pace a working contractor can actually use.

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