Skylight and rooflight installation and replacement in Liverpool
Roof windows, flat rooflights and roof lanterns fitted to Merseyside's terraces, semis and lofts, with the Building Control notification handled.
- 10-year workmanship guarantee
- Building Control notification handled
- Fixed written quote after a survey
- Installation and replacement
Dark landing? Cold loft room? Misted rooflight?
- Light where the house needs it
- Flashed to stay dry in Mersey weather
- Sized to your roof, not a brochure
Our promise, in writing
- A survey before any price
- A fixed written quote
- Building Control handled
- 10 years on our workmanship
How a job runs
- SurveyWe visit and measure up.
- InstallWe fit it properly and keep it tidy.
- Sign-offWe handle Building Control and issue the paperwork.
The Dockside guide
Rooflights for Liverpool homes, start to finish
Skylight and rooflight installation and replacement in Liverpool, fitted to the house you actually have. Building Control handled, 10-year guarantee.
Chapter 01
Which rooflight suits which Liverpool roof
How the pitch, covering, timbers and loft space of Liverpool's house types shape the choice between roof window, lantern and flat rooflight.
Good skylight installation in Liverpool begins with a plain question: what is the roof made of, and what is holding it up? A rooflight that sits happily on a felt flat roof in Childwall would be the wrong thing on a steep slate slope in Anfield. Rooflight installation in Liverpool is mostly about fit. What goes in, and how it is finished, depends on the pitch, the covering, the timbers and the space underneath.
Liverpool was built in waves, from Georgian townhouses to modern estates, and each era built its roofs differently. Here is how that plays out across the districts we work in.
Pitched slate or tile
- Roof window set flush in the slope
- Flashing kit matched to slate or profiled tile
- Width set by the rafter spacing
- Opens for air, with blinds inside
Flat felt, single-ply or GRP
- Lantern or flat glass on a raised kerb
- Membrane dressed up the kerb sides
- Fall built in so water runs off the glass
- Fixed, opening or walk-on
Victorian and Edwardian terraces. The tight streets of Anfield, Walton, Wavertree and Garston are mostly brick terraces under Welsh slate. Slate is thin and flat, and it sits on a steep pitch over slender rafters. That suits a roof window set flush in the slope, with a flashing kit made for slate rather than one made for chunky tiles. The rafters are often close together, so the width of the unit matters. A window that fits between two rafters keeps the job simple. A wider one means cutting a rafter and fitting trimmers either side to carry the load. Terraces with a loft conversion in mind need the windows planned with the room layout, and our guide to roof windows for loft conversions goes through that properly. The back of a terrace usually has a single-storey kitchen or outrigger with its own small roof, which is often the better place for daylight than the main slope.
Bigger Victorian villas. Aigburth and the streets around Sefton Park have larger houses with deep roofs, tall ceilings and attic floors that were built as rooms. Here a top-hung or centre-pivot window from the VELUX range or an equivalent often replaces a small old skylight that was there before.
1930s semis. Allerton, Childwall, West Derby and the edges of Woolton have long runs of interwar semis, many with hipped roofs in clay or concrete tile. A hip leaves less flat slope for a window, and profiled tiles need a deeper flashing than slate. The bigger opportunity is usually at the back. A flat-roof kitchen extension on a semi suits a roof lantern, which throws light down into the middle of a deep room, or a flat rooflight, which keeps a low profile from the bedroom windows above.
Post-war houses and new-builds. Later houses, including many of the estates on the city's outer edges, are often built with trussed rafters. Those are engineered as a set, and you cannot simply cut one out. So the unit is sized to fit between trusses, or the light comes in another way. For a dark landing or bathroom under a trussed roof, a sun tunnel is often the neatest answer, because the tube passes between the timbers without touching them.
Bungalows. A bungalow with rooms in the roof is one of the few places a roof window can also serve as the escape route from a bedroom, because the window is low enough to the ground. The rules on that are specific, and our page on roof windows and means of escape sets them out.
Georgian Quarter and conservation streets. The terraces around the Georgian Quarter, and older village cores such as Woolton, sit in conservation areas where a bulky modern frame would look wrong. A conservation rooflight has a slim frame that sits low in the slate, often with a central glazing bar, and it reads as part of the old roof.
Some flat roofs want more than light. A roof terrace or a basement lightwell can take walk-on glass rated for foot traffic by the manufacturer, and a rooflight that also has to let out steam from a kitchen is better as an electric opening rooflight.
Chapter 02
Signs that an old rooflight has failed, from misted glass to perished flashing, and what skylight replacement in Liverpool involves.
When an old rooflight has had its day
- Mist trapped between the panes
- Brown staining on the ceiling lining
- Soft or blackened timber on the frame
- A dome gone cloudy or yellow
- Flashing lifted or cracked
- Kerb sitting barely above the roof
Every rooflight has parts that age at different speeds. The glass itself lasts. The seal round a double-glazed unit does not last forever, and once it lets in damp air, the air space inside the unit mists and stays misted. No amount of wiping touches it, because the moisture is inside. It is a clear sign the unit is due for rooflight replacement, and the misted rooflight replacement service covers it in detail.
Older units fail in other ways too. Older plastic domes go brittle and yellow in the sun. Timber roof windows from the same era can soften along the bottom rail, where condensation runs down the inside of the glass and sits on the wood. Hinges and handles wear. Flashings perish or lift in a gale. On flat roofs, the old kerb was often a few lengths of untreated timber barely above the felt, and once the roof covering around it has been renewed a couple of times it ends up too low to keep water out.
There is also the simple case of a rooflight that still works but no longer suits the room. A single-glazed skylight over a kitchen extension drips condensation in winter and lets heat straight out. Swapping it for a modern double or triple-glazed unit changes how the room feels, even if nothing was broken.
Replacing a rooflight comes in two broad forms. Sometimes the frame is sound and only the sealed glass unit needs changing. More often, on older units, the whole thing comes out: frame, flashing and all, with a new kerb or new trimming where the old one was short of the mark. Our guide on whether to replace the glass or the whole unit walks through how to tell. For pitched roofs, an old VELUX window can usually be swapped for a new one of the same size code, which keeps the slating disturbance small, and the steps are in replacing an old VELUX window.
Two things catch people out. First, a replacement rooflight is controlled work under the Building Regulations, just like a new one, so it needs notifying and it has to meet today's energy limits. We handle that notification. Second, if the flat roof around the old rooflight is worn out and close to renewal, say so before the new unit goes in, so the two jobs can be planned together rather than one undoing the other. Our full guide to replacing a rooflight covers both.
Chapter 03
Keeping it dry when the weather comes in off the Irish Sea
Where water gets in around a rooflight in Liverpool, and how the flashing and kerb are dressed to keep it out.
Liverpool faces west, and most of its weather arrives the same way: wind and rain off the Irish Sea, driven at an angle rather than falling straight down. Roofs on the coast at Crosby and along the waterfront take the brunt, but the whole city gets enough wind-driven rain to find any lazy detail. A rooflight is a hole in a roof. Everything about fitting one well is about closing that hole properly.
On a flat roof, the rooflight sits on a kerb, also called an upstand. It lifts the glass clear of the roof surface so that standing water and the spray off heavy rain never reach the frame. The kerb has to be tall enough for the unit maker's own fitting instructions, insulated so it does not become a cold spot on the ceiling below, and fixed down firmly to the roof deck. Then the roof covering is turned up its sides and sealed at the top, under the rooflight frame. On felt, that means the felt is dressed up and torched in layers. On single-ply rubber or membrane, the sheet is bonded up the kerb with proper corner pieces. On GRP, the resin is laid up the kerb in one with the roof. Our guide to flat roof rooflight upstands goes further, and so does the page on fitting a rooflight on a felt or rubber flat roof.
Flat glass also needs a fall. Glass laid dead level holds puddles, which leave dirt rings and keep the seals wet. Flat rooflights usually have a fall built into the unit or the kerb so rain runs off one edge, and the roof around the kerb needs its own fall so water moves away rather than pooling at the upstand.
On a pitched roof, the flashing does the work. A roof window flashing kit is a set of interlocking pieces: a bottom apron that lies over the slates or tiles below, side pieces that tuck under the courses either side, and a top piece that runs under the slates above. Behind it, a collar of underlay is lapped into the existing roof felt and a small gutter above the window steers water round the frame. Slate and tile need different kits, and using a tile kit on a slate roof leaves gaps the wind will push rain through. Our guide to roof window flashing on slate and tile shows the difference.
Not every drip is a leak. Water on the inside of a rooflight on a cold morning is usually condensation from the room, especially over kitchens and bathrooms. Good insulation round the lining, a vapour barrier and an opening unit or trickle vent all help, and the page on rooflight condensation explains what causes it.
Rain finds the weakest corner of a rooflight, so the corners get the most time.
Chapter 04
What the U-value measures, and how the glass, the insulation and the lining affect the heat a rooflight lets out.
Heat, glass and Part L
Any new or replacement rooflight in an existing house in England has to meet the energy limits in Part L of the Building Regulations. The figures sit in Approved Document L, volume 1, the 2021 edition, in its table of limits for work on existing dwellings. Roof windows and rooflights have separate limits, because a roof window sits in the slope and a rooflight sits up on a kerb, and they lose heat differently. Roof lanterns count as rooflights. A roof window can also show compliance through its Window Energy Rating instead of its U-value.
The U-value is the measure of heat loss through the whole unit, frame included. Lower is better. A good modern double-glazed unit with a warm-edge spacer and an insulated frame is made to meet them, and a triple-glazed unit goes further. Our guide to rooflight U-values and Part L sets out what each figure means, and the energy-efficient rooflights service has the units themselves.
| Unit | England (W/m²K) | Wales (W/m²K) |
|---|---|---|
| Roof window in a pitched roofWindow limit, or Window Energy Rating band B | 1.4 | 1.4 |
| Flat rooflight on an upstandRooflight limit | 2.2 | 2.2 |
| Roof lanternRooflight limit | 2.2 | 2.2 |
| Walk-on rooflightRooflight limit | 2.2 | 2.2 |
A roof window sits in the plane of a pitched roof and takes the window limit. A rooflight sits on an upstand, usually on a flat roof, and takes the rooflight limit. There is no Building Regulations daylight figure for houses in England, so heat loss is the one number the rules set.
England: Approved Document L, Volume 1, 2021 edition, Table 4.2 (new and replacement fabric in existing dwellings). Wales: Approved Document L, Volume 1: Dwellings, 2022 edition (Wales), Table 10.1 (new and replacement windows, roof windows and rooflights in existing dwellings), in force from 23 November 2022.
Light and heat pull against each other. More glass means more daylight and more heat loss, so the right size is the one that lights the room well without turning the ceiling into a cold sheet. There is no Building Regulations requirement for daylight in a house in England, so the size is your choice, guided by the room and the roof.
Summer matters as well. A big south-facing lantern over a kitchen can make the room uncomfortable on a still afternoon. Solar control glass, an opening vent and a blind all cut the build-up, and the page on rooflight overheating covers the options. On north-facing slopes the problem rarely arises, and the steady, even light there is ideal for a loft office or studio.
Whether to go double or triple glazed depends on the room and how much glass there is. For a small roof window on a landing the difference is slight. For a large lantern over a living space it is worth weighing up, and our guide comparing double and triple-glazed rooflights lays out the trade-offs, including weight, which matters on an older roof.
Finally, the frame is only part of the story. The insulation packed around the unit, the lining that runs from the frame to the ceiling and the seal between them are what keep the room warm. A well-rated unit fitted with gaps around it performs worse than its label. That is why we finish the lining as part of the job rather than leaving it for someone else.
Chapter 05
Planning permission and Building Control, in plain terms
Which jobs need planning permission, which need Building Control and which need both, in plain terms.
Planning first. On a house in England, most rooflights are permitted development under Class C of Part 1, Schedule 2, as set by Town and Country Planning (General Permitted Development) (England) Order 2015. That means no planning application, provided the rooflight projects no more than 150mm from the roof plane and sits no higher than the highest part of the roof. A rooflight on a side-facing slope has to be obscure-glazed, and it must stay fixed shut unless the parts that open are more than 1.7m above the floor of the room.
Those rights cover houses only. Flats and maisonettes do not have them, so a rooflight on a flat in a converted Victorian house in Toxteth or Aigburth needs planning permission. A conservation area changes things too. Several parts of Liverpool are conservation areas, including the Georgian Quarter streets and the old core of Woolton, and a council can use an Article 4 direction to remove permitted development rights there. On a listed building, a rooflight will almost always need listed building consent, whatever its size. Our answer on planning permission for a skylight covers the common cases, and the page on roof windows on the front of the house deals with the slope people worry about most.
- Survey and check. We look at the roof and check for a conservation area, Article 4 direction or listing before quoting.
- Planning if needed. Where the rooflight falls outside permitted development, the application goes in before any work is booked.
- Building Control notice. We notify the work so that it is recorded from the start.
- Inspection and sign-off. Structural or fire details are checked where they apply.
- Certificate. The completion certificate goes in your house file for the day you sell.
Building Control second. A new or replacement rooflight is controlled work under the Building Regulations 2010. The work has to be notified to the local authority building control team, which in the city is Liverpool City Council, or to a registered building control approver, the name used since April 2024. Building Control checks the structure where rafters are cut, the energy performance under Part L and, for a room in the roof, fire safety and escape. When the work is signed off, you get a completion certificate, called a final certificate when an approver did the checks. Keep it, because a buyer's solicitor will ask for it when you sell. We handle the notification for every job that needs it. Our guide to rooflight Building Regulations has the detail.
Across the Dee. Our area runs into north-east Wales, and the rules change at the border. In Flintshire and Wrexham, including around Hawarden, the Building Regulations apply as they stand in Wales, with the Welsh edition of Approved Document L, and building control goes to Flintshire County Council, Wrexham County Borough Council or a registered building control approver. Planning in Wales follows its own permitted development rights, which are not the same as the English Class C limits, and listed buildings there are handled by Cadw. The planning guide points Welsh homeowners to the right source.
Chapter 06
What actually drives the cost
What moves the price of a rooflight job: how the roof is reached, what it is made of, the timbers and the finish inside.
The price of the unit is the part people look up first, and it is rarely the part that varies most. What moves the cost of skylight installation is the work around the unit: how you reach the roof, what the roof is made of, what has to happen to the timbers, and how the inside is finished. Our costs page explains each of these in more depth, and our answer on the cost to replace a skylight covers the replacement side.
Access. A flat roof on a single-storey extension can usually be reached from a ladder or a small tower. A roof window high on the front slope of a three-storey villa in Aigburth needs scaffold, and on a terraced street that may mean a licence from the council to put it on the pavement. Some roof windows can be fitted from inside the loft, which saves on access, and our page on fitting a VELUX window from inside explains when that works.
Structure. A unit that fits between rafters is quick. One that needs a rafter cut and trimmed takes longer and needs Building Control to see the detail. A trussed roof may need an engineer to look at it first, ahead of any cutting. On a flat roof, the joists have to be trimmed round the new opening in the same way.
The roof covering. Old Welsh slate is brittle and the odd one breaks when it is lifted, so matching reclaimed slates are part of the job. On a flat roof, the covering around the kerb has to be cut back and dressed in again. If that covering is tired, it may make more sense to re-cover the area around the rooflight at the same time.
The unit itself. Size, glazing, frame material and whether it opens all count. An electric unit with a rain sensor costs more than a fixed one, and a conservation rooflight or walk-on glass is a different product altogether. Our pages on roof lantern cost and the cost to fit a roof window deal with those choices.
Inside. A new opening needs a lined and plastered reveal from the frame to the ceiling, and decorating. Replacing a unit like for like may need almost none of that.
That is why we survey before we price. A figure given over the phone without seeing the roof is a guess, and guesses grow. After the survey you get a fixed quote in writing, which is the figure you pay unless you change the job.
Adds time to the job
- Scaffold on a high or front slope
- Rafters or joists cut and trimmed
- Brittle old slate or a tired flat roof
- New lining and plastering inside
Keeps it straightforward
- Low flat roof reached from a tower
- Unit sized to fit between timbers
- Like-for-like size code swap
- Existing lining kept in place
Chapter 07
How an install day runs in a house you are living in, from the protection laid down first to the roof being opened and closed.
How an install day runs
A single rooflight or roof window usually goes in over a day or two, and our answer on how long it takes to fit a skylight gives a clearer picture by type. Bigger lanterns, several windows in a loft, or a job that needs the flat roof re-covered around the kerb take longer. Whatever the size, the order of work is much the same.
The first thing in the house is protection. Sheets cover the floor along the route from the door to the room, and over the floor and furniture under the opening. Where the ceiling is coming down, the room gets a sheeted screen so dust stays in one place. On a loft job, the hatch and landing are covered as well.
Survey and booking
Measurements are taken, the unit is made to size, and the Building Control notice goes in.
Sheets down, roof opened
Rooms are protected, the old unit or the roof covering comes off, and the opening is cut and trimmed.
Unit in and weathertight
The frame is fixed, the flashing or kerb is dressed in, and the roof is closed.
Lining and making good
The reveal is insulated and boarded, electrics are tested, and the house is cleaned.
Sign-off
Building Control checks where needed, and the certificate and written guarantee come to you.
The roof is only opened once the new unit, the flashing kit and the timber are on site and checked. We do not open a hole in a Liverpool roof on the strength of a forecast. If the weather turns while the roof is open, it is sheeted and battened down before anyone stops.
Once the unit is in and the flashing or the kerb is finished, the outside is weathertight. Inside, the lining goes in, insulated and sealed, and the reveal is boarded ready for plaster. Electric units are wired and tested with their controls before we leave.
Before we go, the dust sheets come up, the floors are cleaned and the old unit and any broken slate or felt go away with us. You are shown how the window opens and how the blinds or controls work, and any Building Control visit is booked if one is still to come.
Chapter 08
Choosing an installer, and what our guarantee covers
What to ask an installer before work begins, and what the ten-year written guarantee on our workmanship covers.
- Survey before any figure
- Quote that names flashing, kerb and lining
- Clear answer on planning
- Building Control notified, not skipped
- Workmanship guarantee in writing
A good installer should be happy to come out and look before giving a price. They should tell you which unit suits your roof and why, and be clear about whether the work needs planning permission, Building Control or both. Be wary of anyone who says the paperwork is not needed for a replacement, because it is. Be wary too of a quote that lists the unit and a single labour figure with nothing about flashing, kerbs, lining or making good. Those are the parts that keep the room dry and warm, and they are the parts that get cut when a price is squeezed.
Ask how they handle the roof you actually have. A Victorian slate roof in West Derby, a tile roof on a semi in Allerton and a felt extension roof in Walton all need different detailing, and an installer who knows that will say so without being asked. Our house types page shows how we approach each one, from terraces to bungalows. The same thinking goes over the river too, from the villas of Oxton to the coastal semis of Crosby and the terraces of Bootle.
A survey of the roof before any price. A fixed quote in writing. The Building Control notification handled where the work needs it. A reply by phone or WhatsApp, whichever suits you. And once the job is done, a written guarantee on our workmanship that runs for ten years.
That guarantee covers our work: the way the unit is fixed, the flashing and kerb we build round it, and the lining we finish inside. If something we did is not right within those ten years, we come back and put it right. The full terms, including what sits outside it, are on our guarantee page, and they are worth reading before you choose anyone.
If you are planning a rooflight or skylight replacement anywhere in Liverpool, send us a few photos of the roof and the room and we will take it from there. Get a free quote
Guides and answers for Liverpool homes
Guides
- Guide · 9 min readReplacing a Skylight or Rooflight: The Whole JobWhat replacing a skylight or rooflight involves: the survey, like-for-like or a new size, stripping out, a new kerb and flashing, and…
- Guide · 9 min readRooflights and Building Regulations in England and WalesWhich Building Regulations apply when you add or replace a rooflight or skylight: structure, heat loss, fire and safety glass, and who…
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Get a fixed quote for your rooflight
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What happens next: we arrange a survey at a time that suits you, measure the roof and the room, then send a fixed written quote. Nothing is booked until you say yes.