How long does a skylight replacement take?

Like for like, same size: one day

Old unit out, opening checked, new unit in, new flashing kit fitted, tiles reinstated, internal reveal made good where needed. The roof is open for a few hours, not days.

Nearest current size, adapting the opening: one to two days

Adds carpentry to pack out or trim the opening, and more making good inside.

Enlarging the opening: two to three days

Structural work: rafters cut, trimmers installed, more tiles cut and reinstated, a larger reveal formed and finished. On a trussed roof, add the engineer’s design time before anything starts.

Flat roof rooflight replacement: one to two days

If the kerb is sound, one. If the kerb has to be rebuilt, the roof covering around it is disturbed and made good, which adds a day and sometimes more.

The lead time before any of that

Usually the longer part. Stock sizes can be days. Made to size units are typically two to four weeks, and a bespoke lantern three to five.

For flat roof work the unit is ordered from a measured kerb rather than a drawing, so the sequence is survey, order, wait, fit.

What can extend it

Soft timber found when the old unit comes out, which has to be cut out and replaced. We flag it as a possibility at quotation with an indication of cost, so it is a known risk rather than a surprise.

Weather. We reschedule a driving rain day rather than work through it badly, and the roof is made watertight before we leave every day regardless of the stage.

One day for a like for like

A straightforward replacement into a sound existing opening is a single day, and most of that time is spent inside rather than on the roof.

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

Where the day goes

Protection first: floors covered, furniture moved or sheeted, dust barrier at the door. The making good produces the mess rather than the roof work.

Then strip out and inspection of the timber. Then the frame set and checked square in both directions. Then the weathering, in order: underlay collar dressed and lapped, flashing kit fitted, covering reinstated over the flashing. Then the insulation collar and the lining made good.

Then handover: operation demonstrated, cleaning position and filter shown, guarantee paperwork left with you on the day.

What extends it

Altering the opening, where the old size is obsolete. Usually adds a few hours rather than a day.

Decayed timber, which is cut out and replaced. Anything from an hour for a soft corner to a structural repair over a day or more.

A fragile covering. Old handmade clay tiles are slow to lift and a proportion breaks.

Plastering. The work is finished the same day and the drying is not, so decoration follows later and takes longer in a cold house.

Scaffold, which is erected and struck around the fitting rather than on the same day.

What actually delays a job

Almost never the fitting. The lead time on the unit: stock sizes are days, made to measure and conservation units are several weeks. And where consent is needed, months.

The sensible sequence is survey, permission where needed, order, then book the fitting to the confirmed delivery date. Booking the fitting first and hoping the unit arrives is how jobs slip.

Weather

An opening is never left uncovered overnight and a strip out does not start if the forecast will not allow the roof to be closed the same day. That occasionally moves a date by a day and it has never cost a customer a ceiling.

What we need before booking a date

A confirmed delivery date for the unit rather than an estimate, any consent where one applies, and any structural design where the opening is being altered.

We book the fitting to those rather than to a hopeful date, because a date you can plan around is worth more than one that moves twice.

Where a job is urgent because water is coming in, say so at the enquiry and we will treat it as urgent rather than putting you in the queue. Making the roof watertight temporarily is frequently the right first step, because it buys the time to establish what the unit actually is and order the right replacement rather than a hurried one.

Send a photograph of the data plate on the sash and one of the roof from outside, and we will give you a realistic programme along with the price.

The work on the roof

A straightforward like for like replacement, same size, sound timber, accessible roof: most of a day for a competent pair, including stripping the covering back, forming the opening, setting the unit, collar, flashing and reinstating the covering.

Add time for an obsolete size, because the opening has to be packed out or trimmed back and made good.

Add time for timber repair, which cannot be scoped until the old unit is out.

Add substantially for a change of size that involves cutting a rafter.

The parts people forget

Access. A scaffold goes up before and comes down after, which can add days at either end even though nobody is working on the roof.

Plastering. The reveal is made good after the unit is in, and fresh plaster has to dry before it can be decorated. The room is usable but not finished on the day.

Decoration, which realistically means the whole ceiling rather than a patch.

The lead time before any of it

This is usually the longer part.

A stock size arrives in days. A made to measure unit runs to several weeks. A conservation rooflight in a bespoke size, longer. A lantern, longer still.

Where consent is needed it comes first and runs to months. Where structural design is needed, the engineer comes before the order because the opening dimensions depend on it.

The sequence that avoids slippage

Survey, permission, structural design, order, then book the fitting to the confirmed delivery date.

Booking the fitting first and hoping the unit arrives is how jobs slip, and the room stays half finished while everybody waits.