On a residential development, the lowest tender on the roofing package is almost never the cheapest version of the roof. The price that gets accepted at the moment of award is the price for the work performed under best-case conditions. The price the developer actually pays over the life of the scheme is the price plus the cost of programme drift, rework and warranty issues that follow from undercosted execution.
Programme certainty in roofing is what protects against that gap. A roofing contractor who can hold the dates on the programme they were appointed to deliver is, almost by definition, a contractor with sufficient supervision, sufficient material cover, sufficient operative depth, and sufficient internal quality control to absorb the normal contingencies of a live site without slipping.
Contractors who win on price often arrive on site running thin on all four of those resources. Supervision is stretched across more sites than the supervisor can effectively cover. Material orders are scheduled to arrive just in time, with no resilience if the supply chain blips. Operative numbers are tight, so any absence shows immediately in output. Internal quality control is light, which means defects are caught later than they should be and rework cost rises.
Each of these costs the developer days on the programme. None of them shows in the original tender comparison. The roofing rate per metre may be ten percent below the next bid, but if the package finishes four weeks late, the cost of that delay across the broader development is materially larger than the saving.
This is particularly acute on housing schemes where plot release dates are sales-critical. A roofing programme that slips a fortnight pushes downstream trades back. Plot completions slide. Mortgage offers expire on early buyers. Sales programme assumptions break. The cost lands in cash flow and customer experience, not in the roofing budget line.
Globe Roofing prices for programme certainty rather than for the lowest competitive tender. That means margin in the rate, supervisor density at the site, material cover at the depot, and operative depth across the local crew. The bid is not the cheapest. The execution is the most reliable. Across the developers who have worked with Globe Roofing on multiple schemes, the programme reliability is the reason they come back.
For QSs evaluating tenders, the practical advice is to weight programme delivery and operational evidence against price. Ask each bidder how their supervisor density is calculated. Ask what material cover they hold. Ask how operative coverage is managed during peak summer leave. The answers separate contractors quickly.
There is also a track-record question worth raising. A contractor’s recent programme reliability across comparable schemes is a stronger predictor of how they will perform than any tender response. Where references are available from previous developers, talking to those developers about programme reliability is time well spent.
The lowest tender on roofing is rarely the worst outcome. On a small straightforward scheme with low programme risk, it can be the right answer. But on a multi-phase housing scheme with sales-sensitive plot release dates, the lowest tender is structurally biased toward the contractor whose execution is least reliable. That is not where the developer should be optimising for cost.
The cost of programme certainty is small relative to the cost of programme drift. Most experienced developers learn this on a scheme where the lowest bid produced the worst delivery. The cheapest version of the lesson is to learn it from somebody else’s scheme rather than your own.
Talk to Globe Roofing To discuss roofing programme certainty on your residential scheme on your scheme, contact Globe Roofing on 01223 890727 or email enquiries@theglobegroup.co.uk.
