Why Three Envelope Bids Come Back at Wildly Different Prices

A strata council puts its envelope restoration out to tender, receives three bids, and finds the numbers so far apart that the assumption in the room becomes obvious: two of the contractors must have misread something.

Usually nobody misread anything. The three contractors priced three genuinely different jobs, because the document they were given allowed them to. And the gap between those bids is a preview of the change orders the building is going to see once the work starts.

This is one of the most consequential and least discussed parts of a restoration project, and it happens before a single anchor goes up.

What a vague scope does

Consider a line in a tender that reads: replace failed sealant on the north and west elevations.

Every bidder now has to make decisions the document did not make for them.

Does replace mean cutting the existing sealant out entirely, cleaning the joint back to sound substrate, priming, installing backer rod, and applying new sealant? Or does it mean applying a new bead over the existing material? Those are different amounts of labour, and the difference between them is covered in the guide on caulking removal versus cap bead. A contractor who prices full removal is doing considerably more work than one who prices an overcoat, and if the document does not say which, both answers are defensible.

What counts as failed? Visibly split joints only, or every joint on the elevation regardless of current condition? A building with a thousand linear metres of joint might have three hundred that are obviously failed and another four hundred that are near the end of their life. Whether those four hundred are in or out changes the price substantially.

Who provides access? A swing stage or rope access program is a real cost. If the document is silent, one bidder carries it and another assumes the strata is arranging it.

What happens when the sealant comes out and the substrate behind it is deteriorated? Someone has to repair it. If the tender does not address it, one contractor carries an allowance and another excludes it.

Four ambiguities, and the bids are already incomparable. A real tender document has dozens.

Why the low bid is often the expensive one

Here is the mechanism that costs stratas the most money.

The bid with the fewest inclusions is usually the lowest, so it usually wins. Work begins. The sealant comes out, the substrate behind it needs repair, and that repair was not in the contract. It gets added as a change order.

Change orders are priced in a completely different environment from the original bid. There is no competition. The building is already opened up, the access is already installed, and stopping to re-tender the additional work is impractical. The strata’s negotiating position is weak, and the contractor knows the alternative is a half-finished project.

None of that requires bad faith from anyone. A contractor who excluded substrate repair, said so in their bid, and is now being asked to do substrate repair is entitled to be paid for it. The problem is structural: the strata compared incomplete bids as though they were complete, chose on price, and moved the missing scope into a phase of the project where it had no leverage.

The number that matters is final cost, and final cost is determined largely by how completely the scope was defined before anyone quoted.

What a proper scope of work contains

A tender document that produces comparable bids covers six areas.

Quantities and locations. Not “sealant on the north elevation” but the measured linear metres, by joint type, by elevation, with a drawing or an elevation marked up. Quantities come from a condition survey, which is why a building envelope condition assessment usually precedes a tender rather than following one.

Materials and performance. Either named products or a performance specification with the required properties. Sealant is not a generic commodity, and the difference between chemistries affects both price and service life, as covered in the guide on polyurethane versus silicone sealant. Leaving material choice open means bidders will choose differently, and the cheapest choice is not always suitable for the joint.

Methods. Removal versus overcoating. Surface preparation standard. Whether joints get primed. How terminations and transitions are handled. Cure and recoat requirements. Weather restrictions, which matter considerably in a wet climate and are set out in the post on cold weather coating application.

Access. Who supplies it, what type, and what it has to reach. Rope access, swing stage, and lifts have different costs, different setup requirements, and different site impacts, and the comparison is covered in the post on rope access versus boom lift. This item alone accounts for a large share of unexplained bid variation.

Unit prices for unknown quantities. Some work genuinely cannot be quantified until material is removed. Concrete repair is the classic case: you can estimate the area of delaminated concrete from sounding, but the actual extent appears only when chipping starts. The answer is not to pretend the quantity is known. It is to agree a per-unit rate up front and carry an estimated quantity as an allowance. Then when the real quantity turns out higher, it bills at a rate the strata already accepted, in a competitive environment, rather than being negotiated mid-project.

Acceptance criteria. How the completed work is verified. Adhesion testing on sealant joints, described in the post on field pull testing. Coating thickness measurement. Inspection hold points where work must be reviewed before being covered. Without stated criteria, “complete” becomes a matter of opinion, and the strata has no basis to withhold payment for substandard work.

The role of the consultant

For anything beyond routine maintenance, the tender should be prepared by a building envelope consultant or engineer engaged by the strata.

The reason is independence. A consultant retained by the owners has no interest in which bidder wins. They can survey the building, quantify the work, specify materials on technical grounds, write acceptance criteria they will enforce, and review change order requests on the strata’s behalf during construction. The distinction between that role and the contractor’s is set out in the post on envelope engineer versus contractor roles.

Councils sometimes look at the consultant fee and decide to save it by having a contractor write the scope. On a small, clearly bounded job that can work, provided every bidder receives an identical document. On a substantial restoration it usually costs more than it saves. The strata ends up with bids that cannot be compared, no independent verification that work was done as specified, no enforceable acceptance standard, and no technical authority on their side when change orders start arriving.

The fee is frequently less than the change orders a well-written scope prevents.

How to compare bids properly

Do not compare totals. Build a table.

List every scope element down the side and each bidder across the top. For each cell, record what that bidder included, explicitly excluded, or left unaddressed. Read the exclusion clauses carefully, because that is where the differences live, and they are often in small print at the end.

Then normalize. Where one bidder excluded something the others carried, add a reasonable allowance for it to their number. Where a bidder carried an allowance and another carried a firm price, note the difference in risk. Compare unit prices as their own line, separate from lump sums, because a low lump sum paired with high unit rates on the uncertain quantities is a common shape.

Bids that looked far apart usually converge substantially through this exercise. The remaining spread reflects genuine differences in approach, overhead, and how each contractor assessed the risk, which is the comparison a council actually wants to make.

Two further checks are worth the time. Ask each bidder for recent projects of comparable type and scope, then call those stratas and ask specifically about change orders, schedule performance, and how the contractor handled conditions nobody anticipated. And confirm insurance, WorkSafeBC standing, and the qualifications relevant to the access method, which for rope access means certified technicians and a written rescue plan.

Give the tender enough time

A short tender period produces higher prices. A contractor who has not had time to visit the building properly, review the documents, and get subtrade pricing will add contingency to cover what they could not verify. The strata pays for that contingency in the bid whether or not the risk materializes.

Allowing enough time for a proper site visit, a question period where bidders can seek clarification, and written answers circulated to everyone, costs nothing and produces sharper pricing. The question period is particularly valuable, because the questions bidders ask reveal exactly where the scope is still ambiguous, and the answers go to every bidder so nobody is pricing on private information.

The short version

Widely varying bids are a symptom of a scope that let bidders make their own assumptions, and those same assumptions become change orders once the work starts.

Define quantities, materials, methods, access, and acceptance criteria. Set unit prices for the work whose extent cannot be known until it is opened up. Have the document prepared by someone working for the owners. Compare bids line by line rather than total to total. Give the tender enough time to be priced properly.

None of this makes the project cheap. It makes the final number close to the number the council approved, which is what most stratas actually want.

Sources and further reading

• Canadian Construction Documents Committee, CCDC 2 Stipulated Price Contract, referenced 2026
• BC Housing, Building Enclosure Renewal Guide, referenced 2026
• Strata Property Act (British Columbia), contracting and approval provisions, referenced 2026
• WorkSafeBC, Occupational Health and Safety Regulation Part 34 (Rope Access), referenced 2026
• Allweathercoating tender and project records, Metro Vancouver, 2026