Last updated: September 2026
A specification gets written. Your product is on the drawings. Months later the order goes to a competitor, sometimes to an import you have never heard of. The rep did the design-stage work well and still lost the job at the final gate.
That is specification leakage. In my experience it is one of the most common frustrations I hear from sales leaders in building products, and it is worth being precise about what it is and where it happens before deciding it is a hiring problem. This post is for hiring managers, GMs and MDs who keep seeing strong specification activity and weaker revenue.
What is specification leakage in building products sales?
Specification leakage is when a product or system is specified at the design stage and then does not convert into the installed or ordered outcome. The rep wins the specification. The company does not win the order.
The cheaper substitute is only one way this happens. A specified product can also fall out because of stock availability, program pressure, an installer's preference, approved-equivalent wording (specification text that allows a product "or approved equivalent"), a service or warranty concern, or a compliance decision. Cost is a common cause, not the definition.
It sits in the gap between two stages with different priorities. The architect, engineer, designer or specifier who writes the specification is solving for performance, compliance and aesthetics. The contractor, builder, quantity surveyor (the person who measures, prices and advises on project cost) or procurement team who buys is solving for cost and program. When those priorities diverge, the specified product is exposed, and the rep often hears about it only after the decision is made.
Before you blame the rep, run this four-part diagnostic
Before you write off the rep, run four questions across the lost specification. They separate a people problem from a specification, coverage, commercial or delivery one.
1. Specification quality. Was the performance requirement clear and defensible, or loose enough to invite an equivalent?
2. Stakeholder coverage. Did the team cover who specifies, who approves, who buys and who installs?
3. Commercial defence. Could the rep explain performance, risk, warranty and total cost when challenged?
4. Delivery capability. Could the business actually supply, support and install the promised outcome, including stock and lead times?
Only after those four check out is it fair to look at the hiring profile.
Where does a specification actually leak?
Leakage does not happen at one fixed point. It helps to name the project stage rather than talk about problems being "upstream" or "downstream". The table below sets out where a specified product tends to become vulnerable, who makes the call, what to gather, and what it means for hiring.
| Project stage | Common leakage cause | Who decides | What to check | Hiring relevance |
|---|---|---|---|---|
| Design | Specification written too loosely or with open equivalents | Architect, engineer, specifier | Whether the spec was closed, proprietary or performance-based | Can the rep help shape a defensible specification |
| Tender | Substitute offered against a tight program or budget | Head contractor, estimator | Whether the rep was in the tender conversation at all | Contractor-side knowledge |
| Procurement | Cheaper equivalent proposed to hit a cost target | Contractor proposes, contract administrator assesses, principal approves. The quantity surveyor prices it and advises | Who actually approved it under the contract, and what evidence the contractor put up | Commercial defence under challenge |
| Delivery | Specified supplier cannot meet the program and a competitor with local stock steps in | Contractor, project manager | Stock position and lead times confirmed before procurement | Delivery capability, largely outside the rep's control |
| Installation | Installer swaps for a product they prefer or already have on hand | Installer, applicator | Installer relationship and coverage | Channel coverage and follow-through |
Value engineering, the process of finding a cheaper way to hit the same brief, drives most of the tender and procurement rows. The delivery row is the one managers most often miss, and the clearest case where a capable rep can still lose the job.
How much does one lost specification cost?
Few of the businesses I deal with ever total this up. Beyond the obvious gross margin on the lost order, the fuller cost adds the rep's hours over a specification cycle that in chemicals and envelope often runs well over a year, and the cost of a specifier now less likely to push for your product on the next job.
Here is one illustrative scenario using assumed inputs, not an industry average. Change any number and the total moves. A $400,000 specified package at a 35% gross margin is $140,000 of margin gone when the substitute wins. If a rep loses five of those in a year across a team of six reps seeing the same pattern, the assumed figure runs into the millions before commission, time and downstream revenue. The order of magnitude is what makes managers pause. If you want a structured way to run your own figures, the cost-of-a-bad-hire calculator sits next to this, not inside it.
Specification count alone will not tell you whether leakage is happening. Better leading measures are specification-to-tender retention, tender-to-order conversion, the reason given for each substitution, the stage at which the loss happened, and how long it took to discover.
Which rep capabilities defend a specification?
Four capabilities tend to decide whether a rep defends a specification or watches it go.
Technical reasoning under pressure. Can the rep hold the technical argument when challenged, not just describe the product? When a quantity surveyor says there is something that does the same job for less, can the rep explain where the substitute differs on performance, warranty or compliance for this specific application? This is worth testing against a real application rather than a general pitch, because the relevant standard depends on the use, and asserting a breach that does not actually apply does more harm than good.
Commercial grit and ownership. This is more than resisting a bullish buyer. The attribute that matters most, in my experience, is the drive to stay involved through the whole project and see it through to delivery. Winning the design-stage specification is one part of the job. Following it through procurement and delivery, and staying in front of the people who can substitute it, is the rest.
Contractor-side knowledge. Does the rep understand who actually buys, and how those buyers think? A rep who only speaks specifier will not see a substitution coming. This covers contractor procurement, where substitutions get approved, and how merchants decide what to stock. It builds slowly and is hard to fake, so it is worth weighting at hire rather than assuming it can be added quickly during onboarding.
Moving a price conversation to total cost. Can the rep move a price conversation to a total-cost or risk conversation in language the buyer respects? Effective framing names a specific failure mode, puts a cost against it, and prices the specification accordingly. Weaker framing leans on "you get what you pay for", which buyers discount immediately.
How do you test those capabilities in hiring?
Some of this can be tested at hire, and some has to be built afterwards.
Commercial drive is usually visible in an interview. Candidates motivated by commission and a sales budget tend to show it, so test it directly and verify it against their history rather than trusting enthusiasm on its own. End-to-end ownership is best tested by asking for a real example the candidate followed from early specification through order and delivery, including what changed along the way and where they stayed involved.
Product knowledge is learnable, but it takes time. The more useful question at hire is which candidate is closest to the relevant market segment, because someone who already understands the buyers, the project stages and the route to market has less to learn, even coming from an adjacent product. Exact product experience is not always required.
Keep a substitution scenario in the process, but treat it as one input alongside work-history probes and references, not a single predictor. Try this one: "You specified Product A on a $20m hospital project. The quantity surveyor has come back with a substitution at a lower price, and the builder's program is tight. What is your call in the next 48 hours, and what is the email you send the architect?" A strong answer identifies the stakeholders, the documents, the technical proof, the timing and the next action. A weak one only pushes back on price. I keep a fuller set of interview questions for building products sales worth running before your next round.
How specification leakage differs by sector
Leakage does not happen at the same point in every sector. The table below shows where the decision tends to move. The detailed hiring profile for each sector lives on its own page.
| Sector | Where the decision moves |
|---|---|
| Construction chemicals and waterproofing | Substitution at procurement or site, across a specifier, installer and distributor triad. The applicator shortage and what it does to a sale sits underneath a lot of this. Hiring waterproofing sales reps. More on civil and chemicals hiring |
| Building envelope and facades | Compliance and warranty exposure raises the technical bar, so a value-engineered substitution risks more than margin. Hiring roofing, cladding and facade reps. More on envelope hiring |
| Civil and infrastructure | The specification is shaped before tender, so the defence happens well before the RFQ. Hiring civil and infrastructure reps. Civil sales recruitment guide |
| Commercial interiors | The design firm wins the look, then the fitout contractor can swap on the way to site, sometimes for stock reasons rather than cost. Related: why your best A&D reps are leaving. More on interiors hiring |
| Architectural lighting | A cheaper import gets dropped in at tender, and the designer community is small enough that reputation travels quickly. Lighting industry profile. More on lighting hiring |
Two examples are worth spelling out. In civil, the order is usually not lost to a substitute at site. It is shaped before tender by a supplier who got there first, often more than a year out, which changes what defending the specification means. As I have put it before, you wanted someone who shapes specs and you got someone who quotes specs, and the market is full of the second. In envelope and facades, the risk sits on top of the margin, because a value-engineered substitution can weaken the compliance and warranty position, which is why the technical bar for a rep is higher here than almost anywhere else.
Public data gives a sense of the stakes without measuring leakage directly. The 2025 Strata Defects Research Report from Building Commission NSW surveyed 520 NSW Class 2 strata buildings registered between July 2018 and June 2024 and found serious defects in 53% of them, waterproofing defects in 44% and fire-safety defects in 28%. That measures defect prevalence in a specific building class, not the rate of specification substitution, but it shows why a weakened waterproofing or facade specification is not only a margin question.
When is it actually a hiring problem?
Repeated leakage can expose a hiring-profile gap, but only after the specification, stakeholder, commercial and delivery causes have been checked. Plenty of specifications are lost for reasons no sales hire can fix.
The clearest example I have seen is supply. A rep can win and defend the specification properly and the manufacturer can still lose because it cannot deliver. I have watched businesses unable to supply specified products through global supply-chain disruption, while a competitor with stock on hand stepped in and replaced the specification quickly. The product sells and the install stalls, and the delay started somewhere the sales team did not control.
One from the desk, details changed. A supplier hired a likeable, well-presented rep who knew the product cold, and for a while it looked like a good hire. The gap showed up at the contractor stage. When a cheaper alternative was pushed at procurement, the rep had the relationship with the architect but no real standing with the builder or the installer, and could not defend the specification through the substitution. The spec was lost on a project that should have held. The missing capability was not product knowledge or charm, it was contractor-side credibility and the technical reasoning to defend the choice under pressure.
So the honest rule is a sequence. Check the specification, the stakeholder coverage, the commercial defence and the delivery capability first. If those are sound and the same reps keep losing at the substitution stage, the brief is probably selecting for the wrong things, perhaps product knowledge over ownership, or likeability over technical reasoning. That is a hiring conversation, and a generalist recruiter will struggle to see it, because they do not know what specification defence looks like in your sector. It is most of why I built a specialist building products recruitment agency.
What a hiring manager can change on Monday
- Rewrite the brief around the project stage where you actually lose specifications, not a generic list of attributes.
- Run a substitution scenario in the next interview round and score it on stakeholders, documents, technical proof, timing and next action.
- Check the candidate's contractor-side history, and ask for one project they owned from specification through to delivery.
- Use references to test follow-through, not just whether the person would be rehired.
For the distinction the brief most often turns on, spec manager versus BDM covers it, and the technical sales role taxonomy sets out the titles and sales motions behind them.
Where these numbers and observations come from
- The NSW defect figures come from the 2025 Strata Defects Research Report by Building Commission NSW, covering 520 surveyed Class 2 strata buildings. It measures defect prevalence, not the rate at which specifications get substituted.
- The substitution mechanics (who proposes, who assesses, who approves) follow NATSPEC TECHnote GEN 006, Product specifying and substitution (April 2024) and the Australian Institute of Architects' Code of Novation (February 2022). Naming a proprietary item in a NATSPEC specification indicates the necessary properties of the item, not an exclusive preference, and the contractor may propose an alternative for the contract administrator's evaluation. No source read gives a quantity surveyor approval authority over a substitution.
- The cost figures are an illustrative scenario using assumed inputs from roles I recruit, not a market average. Replace them with your own.
- The cycle-time comments, and the capability, ownership and adjacent-sector points, are my own observations from the briefs, calls and placements I handle, offered as experience rather than national statistics.
If you have a specification-led role and are not sure whether the profile matches the point where you keep losing, get in touch. I run sales recruitment for the Australian building products industry, and I am happy to pressure-test the brief before you run it.
James