Replacing several rooflights at once

What is shared

Scaffold. The dominant cost on anything above single storey. Erecting for one window costs nearly the same as for three on the same elevation.

Setting up. Sheeting, protection, tools, materials on site.

Travel and mobilisation. One visit rather than several.

Waste disposal. One collection.

What is not shared

The units themselves, and the labour of fitting each one. So the saving is real without being dramatic: three units in one visit might cost twenty to thirty per cent less than three separate visits.

On a scaffolded elevation it is more.

The appearance argument

Frame profiles and cladding colours change over the years. Replacing all the windows on one slope together means they match. Doing them one at a time over a decade means three visibly different generations on one roof.

Phasing sensibly

Where budget does not allow all at once, phase by elevation rather than by urgency. All the windows needing the same scaffold, done together.

Replacing one from the front and one from the back means paying for access twice.

Ask about the extra one

If two of three are misted and the third is not, ask what it costs while the scaffold is up. It is usually much less than doing it separately in two years, and it will need doing.

The single most reliable way to spend less

Access is a fixed cost shared across everything done in the same visit. Scaffold, a tower, a highway licence, setting up, protection and clearing away are paid for once whether we replace one unit or four.

That means two windows replaced together cost meaningfully less than two replaced a year apart, and on a property where the access is expensive, which is most terraced and two storey work, the saving is substantial rather than marginal.

Why the second one is coming anyway

Sealed units last fifteen to twenty five years. Units fitted at the same time have taken the same weather, the same thermal cycling and the same number of daily expansion and contraction cycles, so they fail at about the same time.

If two of three on a slope have misted, the third is not far behind. Replacing it now costs a fraction of replacing it separately in two years, and you will not be paying for the access twice.

The same logic applies to a whole loft conversion done in the 1990s. If one window has gone, the others are the same age.

Matching, which is the other argument

Cladding colours have changed several times over the decades, sightlines have generally slimmed so a modern unit shows more glass and less frame, and older units frequently sit differently relative to the covering.

Replacing one out of three on a visible slope leaves a mismatch. On a rear slope nobody sees, that is easily accepted. On a front elevation, or in a conservation area where a replacement may be conditioned to match the existing, it matters, and replacing them all is frequently better value than it first sounds.

What we actually do

Quote the whole slope, itemised per unit, so you can see what each one costs and decide. Where you want to do two now and one later, that is your call and we will price it honestly rather than pushing the larger job.

What we will do is tell you plainly what the third one will cost separately, so the decision is made with the real numbers rather than a vague sense that it can wait.

Programme

Two or three replacements in one visit is two to three days rather than three times one day, because the access, the protection and the setting up are shared and the second and third go faster than the first.

Where the units are the same model and size, the order is a single delivery. Where sizes differ or one is obsolete, we establish that from the data plates before ordering rather than discovering it on the day.