Why the Cheapest Atrium Quote Usually Is Not

Put three quotes for the same atrium side by side and the lowest one is usually lowest because it’s answering a smaller question. Not because the firm is cheaper, and not usually because they’re cutting corners on purpose. They’ve scoped less, and the gap turns up later as variations.

Spotting which kind of cheap you’re looking at takes about twenty minutes with the three documents and a short list of things to check.

The access is where the money is

On any high-level glazing job, getting to the glass costs more than the glazing work. That’s the single fact that explains most of the spread between quotes.

So the first question for a low number is what it assumes about access. Rope access from existing anchors is cheap if the anchors exist and have been tested. If they haven’t, the real job includes anchor installation and testing, and the quote that left it out is a quote for a different job.

Mobile plant is cheap if the floor takes it. Lobby slabs over basements frequently don’t, and that’s an engineer’s call rather than a hire company’s. A quote that prices a scissor lift without anyone having checked the slab design has priced an assumption.

Scaffold is honest about being expensive and then gets undercut by the two methods above, right up until the point where neither is available.

What tends to sit outside the low number

Six things, and they recur.

Anchor testing or installation, as above. Out-of-hours working, which gets priced at day rates by firms assuming the space will be empty. Protection and enclosure below the work, which in a space with people in it is a real cost rather than a roll of tape. Waste glass removal, which is heavier and more awkward than it sounds. Making good internally where framework has been disturbed. And the survey itself, where a contractor has priced from a photograph and will reprice once someone has actually been up there.

The honest version of the last one is a two-stage quote: a price for the survey, then a price for the work against what it found. That reads as less decisive and is usually the more reliable document.

The repair that doesn’t hold

There’s a class of cheap that isn’t about scope at all. It’s a method that costs less and lasts a season.

Running fresh silicone over hardened silicone is the commonest example on an atrium. It looks like a repair, it’s quick, and it fails because the new material bonds to the old material rather than to the substrate, so the joint it’s meant to be sealing is still moving underneath it. The proper version is cutting the old material out, preparing the surfaces and remaking the joint, which takes considerably longer and costs accordingly.

Patching a failed sealed unit is another. There’s no repair for a broken edge seal; the moisture is inside a cavity nobody can reach. A contractor offering to sort out misting without replacing the unit is offering to clean the inner face and hope.

Aggressive chemicals on coated glass belong in the same category. They save an hour and degrade the gaskets, and the building gets a leak eighteen months later from a cleaning decision.

Perimeter seal failure is the one that hides best, because the water appears a long way from the fault, so a price to reseal part of a joint deserves a question about how the rest of it was assessed.

How to make the quotes comparable

Commission the survey separately. One fee, done once, and then all three contractors price the same defined defect register rather than each pricing their own guess.

That removes most of the spread, and what’s left is genuine difference in rates and method. It also means the lowest number is now comparable instead of just lowest.

Then require four things in writing from each quote: how access is achieved and on what authority for the loading or the anchors; whether access and glazing are both in-house; what the rescue arrangement is, named rather than implied, since the Work at Height Regulations require the plan to set it out; and what’s excluded, listed explicitly.

The exclusions list is the most informative page in any glazing quote and the one most owners don’t ask for.

What a fair price looks like

Specified against a survey, with the access method justified, both disciplines held in one business so neither can be blamed on the other, and the exclusions stated. Specialists such as skyaccessglazing.co.uk work to the inspection and performance guidance the Centre for Window and Cladding Technology publishes, which is what most specifications reference and a reasonable thing to ask a contractor to price against.

Where there are glazed screens or partitions in the same space, get them into the same scope. One mobilisation covering both beats two, and the balance between privacy and light in glass partitions covers the decisions that tend to come up when they’re replaced.

A quote you can’t see the exclusions on isn’t a lower price. It’s a smaller document.