Can you fit a rooflight to a tiled roof?
Yes, and it is the most common installation there is. A tiled slope is the substrate a roof window was designed around, and every manufacturer publishes a flashing kit for each family of tile. What changes from one house to the next is not whether it can be done but how long the tiling itself takes, because a hand sorted clay peg tile and a deep profile concrete interlocking tile are two quite different mornings of work around the same opening.
This page is about the covering rather than the timber underneath it. The structural side, trimming rafters and forming the opening, sits on the roof window installation page. What follows is what the tiles themselves dictate about size, position and the sequence on the day.
Yes, and the tile itself sets the method
The flashing kit is ordered against the covering, not against the window. Every manufacturer produces at least three variants: one for flat coverings such as slate and plain tile, one for profiled tiles up to a stated depth, and one for deep profiles. The apron in each is shaped differently, because its job is to sit down onto the surface without bridging a void that wind can get into.
Get that choice wrong and the geometry does the damage rather than the workmanship. A flat kit laid over a deep pantile leaves an unsupported span over every trough, which lifts in a gale and lets rain drive underneath in exactly the place the apron was meant to protect.
The tile families found on Essex roofs
The county covers most of the English range, and the age of the house is a reliable guide to what is on it.
| Covering | Where it turns up | What it means for the work |
|---|---|---|
| Plain clay tile, machine made | Interwar semis, most commuter towns | Straightforward, soakers between courses |
| Handmade clay peg tile | Thaxted, Coggeshall, Saffron Walden, older Maldon | Slow, sorted by hand, cut pieces bedded |
| Concrete interlocking, low profile | Fifties to seventies estates | Standard profiled kit, quick |
| Concrete or clay pantile, deep profile | Braintree, Colchester, Suffolk border | Deep profile kit, tile-and-a-half at verges |
| Modern flat interlocking | Great Notley, Beaulieu Park, newer estates | Flat kit, recessed option reads well |
Batten gauge, and why the opening lands where it does
Tiles hang on battens at a fixed spacing, called the gauge, which is set by the tile length and the head lap the pitch requires. Nothing about an opening changes that spacing, so the head and sill of a window relate to whole courses whether or not anybody planned it that way.
A good installer sets the opening out so that the head lands just below a batten line and the sill just above one. That way the courses above and below the window run through with a full tile rather than a sliver, and the finished slope reads as though the window was in the original setting out. Moving a window twenty or thirty millimetres to achieve that is free at the marking out stage and impossible afterwards.
Setting out to whole courses where possible
The same logic applies across the width. Tiles have a fixed cover width, and an opening that lands mid tile on both sides produces two narrow cut pieces that are difficult to fix securely and catch the eye from the garden.
Where the room below allows any latitude, the opening is shifted so that the cuts either side are at least half a tile wide. Half a tile takes a nail and a clip. A forty millimetre sliver takes neither, and ends up bedded in mortar or held on a rivet, which is a detail that works but announces itself for the next thirty years.
Cutting tiles down the sides of an opening
Cut tiles are the part of a tiled installation that separates careful work from quick work. Each one is cut wet on a bench rather than dry on the roof, so the edge is clean and the dust is controlled, then holed for a fixing rather than nailed through the tail where it would crack.
On plain tiles, cut pieces sit within a broken bond and disappear. On interlocking tiles the cut removes the interlock on one side, which is why cut pieces at an opening are clipped or riveted rather than left to sit. On a slate roof the equivalent detail uses a copper disc rivet, and that is covered on the main installation page.
Handmade clay, and the slower version of the job
Handmade tiles across the older Essex villages come in a range of cambers, thicknesses and colours within the same batch, and the roof they are on was laid by somebody sorting as they went. Working into that roof means matching the sorting rather than the specification.
Tiles taken off around an opening are kept in the order they came off and set back in roughly the same zone, so the weathered faces stay together. New tiles introduced into the middle of an old slope read as a bright rectangle for years, so where extra tiles are needed they go at the verge or the eaves and the older ones move inward. This is why a window into a handmade clay roof runs to two days where the same window into a concrete tile roof is one.
Deep profile tiles, and the trough that has to be bridged
A pantile or a deep interlocking concrete tile has a pronounced roll, and the apron of the flashing has to be dressed down into each trough to make a continuous line. The dressing is done by hand with a bossing stick, working the lead or the aluminium down into the profile until it takes the shape of the tile rather than sitting proud of it.
Deep profiles are also the case where a recessed flashing gains least. Recessing drops the frame lower into the structure so the glass sits close to flush, which reads beautifully against a flat tile or a slate. Against a bold roll the eye reads the profile anyway, so the extra cost buys very little.
Spare tiles, and where the shortfall comes from
Some tiles break coming off. That is normal on any roof over about forty years old, and the sensible allowance is a modest surplus rather than an exact count. Where the house has a stack of spares in the garage, they get used first.
Where it does not, the options are a reclamation yard for a discontinued pattern, a current equivalent from the same manufacturer where the pattern is still made, or careful relocation of sound tiles from a less visible slope. All three are settled at survey, because a discontinued handmade tile can take a fortnight to source and that sits on the programme rather than on the day.
What a tiled slope is checked for before a price
The survey looks at the tile type and its condition, the batten gauge, whether the battens are sound enough to take a fixing at the edge of a new opening, the underlay behind them, and the pitch. Old bitumen felt that has gone brittle is cut back to sound material and lapped over rather than left to crumble at the head of a new frame.
It also looks at what a slope has already had done to it. Foam sprayed under the tiles, mortar bedded verges from a previous era, and tiles nailed every course on an exposed elevation all change how far the covering has to be disturbed. Costs across covering types are set out on the costs page, and the flashing detail for slate on the main installation page.
Tell us about your roof
We start with the building, the covering and the slope. Then we tell you what will suit it, and what it will cost, as a fixed written number.
- Surveyed before it is priced
- 10-year workmanship guarantee
- Building Control notification handled
- New installations and replacements