Can you match my existing rooflight?

If the size is current

Straightforward. The new unit goes into the existing opening, a new flashing kit is fitted to suit the covering, and it is typically a one day job.

You get twenty five years of glazing improvement for free: low emissivity coating, argon fill and a warm edge spacer are all standard now and none was standard then.

If the size is obsolete

Nearest current size, adapting the opening. Usually the best answer. Current sizes are often within 40mm or 60mm, and adapting is modest carpentry, invisible when finished. It leaves you standard for the next thirty years.

Another manufacturer at the old dimension. Worth checking where the opening is awkward to alter, for instance tight against a purlin or a steel.

Reframe to a current size. More work now, right where the opening is genuinely awkward or where the timber needs replacing anyway.

Matching appearance across a roof

Where you are replacing one of several and want them to look consistent, tell us. External cladding colour, glazing bar position and frame proportions vary between manufacturers and generations, and a mismatched pair on one slope is obvious from the garden.

Sometimes the honest advice is to do all of them, particularly where the others are the same age and will fail within a few years anyway.

What we will not do

Force a unit into an opening it does not fit and pack the gap. It looks acceptable for about a year, then the packing settles and the sash stops closing square.

Usually, and how closely depends on the age

Start with the data plate. Photograph it rather than transcribing it: it is on the top edge of the sash or the frame beside the hinge, and on a centre pivot window rotating the sash brings it into view.

From that we can tell you the manufacturer, the model and the size code, and whether the same unit is still made. Where it is, a like for like replacement is straightforward and it will look identical alongside the others.

Where the size is obsolete

Normal on anything fitted before about 2000. Three routes, and each affects matching differently.

Adapt the opening to the nearest current size. Usually within 40mm or 60mm, so the new unit sits slightly differently but reads as the same from the ground. This is normally the right answer.

Find another manufacturer at the old dimension. Keeps the opening untouched and gives you a mixed set of windows on one roof, which may or may not matter depending on the elevation.

Reframe to a current size, which makes sense where several are being standardised.

Why a new unit looks different anyway

Even a same manufacturer replacement will not be identical to a twenty five year old window, and it is worth knowing before rather than after.

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.

Where the manufacturer offers a matching cladding colour, that gets you most of the way for very little.

Where matching matters

On a front elevation, or any slope seen from a public vantage point. In a conservation area, where a replacement may be conditioned to match the existing. And on a row of identical properties, where one different window on the street is noticeable.

On a rear slope nobody sees, accept the difference and save the money.

The argument for doing them all

Units fitted at the same time fail at about the same time, and access is a fixed cost shared across everything done in the same visit. On a visible slope, replacing all of them is frequently better value than it first sounds and it removes the matching question entirely.

We quote the whole slope itemised so you can see what each one costs.

What we can match, in order of difficulty

Same model, same size, still in production. Straightforward. The plate tells us everything and the replacement is identical.

Same manufacturer, current equivalent of a discontinued model. Usually very close. Ranges evolve but the visual language stays consistent, so a modern equivalent beside a twenty year old unit reads as a matched pair from any normal viewing distance.

Same size, different manufacturer. Achievable dimensionally, visibly different in the room. Frame proportions, the way the sash sits within the frame, and the external cladding profile all differ. On a slope with three existing windows, a fourth from another maker will be noticed from inside even if it is invisible from the ground.

An obsolete size. Then matching means either adapting the opening to a current size, or accepting a made to measure unit at the original dimension with the lead time that implies.

What we need from you to answer properly

A photograph of the data plate on the top edge of the sash or the frame beside the hinge, taken close up with the flash on. That one image usually settles the whole question in a minute.

Failing that, a photograph of the window from inside showing the full frame, and one from outside if you can get it safely. We can narrow it to two or three candidates from those and confirm on survey.