Roof lantern repair questions

Most roof lantern leaks come from a failed seal, a lifted or cracked top capping, a blocked eaves gutter or a badly sealed junction between the flat roof and the upstand. Less often the cause is a slipped glass unit, a split ridge end cap or a vent that no longer closes tightly. Water can travel along the bars before it drips, so the drip is rarely directly below the fault. Our guide why is my roof lantern leaking? walks through the usual causes.

Yes, in most cases a leaking roof lantern can be repaired without replacing it. The usual fixes are resealing, renewing gaskets, re-seating or replacing top cappings, clearing and resealing the eaves gutter, or repairing the flat roof junction at the kerb. Replacement is usually only worth considering when the frame itself is rotten, badly distorted or failing in several places at once. Our roof lantern leak repair page explains what is involved.

We find a leak by inspecting the lantern inside and out and, where needed, water testing one section at a time while someone watches inside. Testing usually starts at the lowest point, such as the kerb and eaves gutter, and works upwards to the bars, hips and ridge so each area is ruled in or out. After a leak investigation visit you get a written report with photos and the repair we recommend.

It can be either, and the two are often confused because water from a failed flat roof junction can show up inside the lantern. Clues include staining at the base of the lantern rather than along the bars, and leaks that appear after long spells of rain rather than wind-driven showers. The junction between the roof covering and the upstand is a common weak point. Our guide flat roof or lantern leak? explains how to tell them apart.

A lantern that only leaks in storms usually has a small gap that lets water in only when rain is driven sideways or the gutter overflows. Typical culprits are a lifted wing gasket, a failed ridge end cap seal, a gap at the hip caps or an eaves gutter that cannot clear a downpour quickly enough. Photos of where the water appears, and a note of the wind direction, help narrow it down. See roof lantern leaking in a storm.

Yes, condensation is often mistaken for a leak because it can run down the glazing bars and drip from the eaves. Condensation tends to appear on the inside of the glass on cold mornings or after cooking and showers, whether or not it has rained. A leak usually follows rain and appears in the same place each time. If you are not sure, send photos and we will tell you what we think, or read our roof lantern condensation guide.

Catch the water, protect what is underneath and keep electrics dry, but do not climb onto the flat roof yourself. Put down a bucket or towels, move furniture and rugs, and switch off any lights or sockets that are getting wet. Take photos inside and out from a safe place to send us. If water is coming in heavily, or glass is cracked, ask about an urgent make-safe, which we arrange as soon as we can.

Misting between the panes means the edge seal of the sealed unit has failed and moist air has got into the cavity. Once the desiccant in the spacer bar is saturated, the moisture shows as fog or droplets that come and go with the temperature. The inside of a sealed unit cannot be cleaned or dried out reliably, so the usual fix is a new unit made to measure. See misted glass unit replacement and our guide to misted roof lantern glass.

Yes, individual glass units can usually be replaced without disturbing the rest of the lantern. We measure the unit, have a new one made to the same specification or an upgraded one, then lift the cappings, swap the glass and reseal. Guide prices are £245 to £595 per misted unit and £295 to £795 per cracked unit, ex VAT, depending on size, glass and access. The fixed price is confirmed in writing before any work starts.

Most roof lanterns use a double-glazed sealed unit with a toughened outer pane and, ideally, a laminated inner pane. Industry guidance from the Rooflight Association, publicised in January 2026, recommends a laminated inner pane for overhead glazing, and British Standards already require one where a rooflight is more than 5 m above floor level or over water. Low-E coatings, argon fill, solar control and self-cleaning glass are common options. See laminated vs toughened roof lantern glass.

A cracked pane should be treated as a safety risk until it has been checked, because the type of glass decides how it is likely to fail. A cracked laminated pane usually stays in place, while broken toughened glass breaks into small pieces that can hang in the frame and then fall. Keep people out of the area underneath, do not touch or tape the glass from a ladder, and send us photos. We arrange an urgent make-safe as soon as we can, then replace the unit.

A panel usually slips because an end stop has broken or worked loose, setting blocks are missing, or the cappings no longer clamp the glass firmly. You may see a gap at the ridge, glass overhanging the eaves gutter, or a leak at the top of the bar. We reset the unit, fit or renew the stops and packers, and reseal it. The guide price is £195 to £445 per panel ex VAT, with the fixed price confirmed in writing before any work starts. See slipped glass panel repair.

Roof lanterns get condensation when warm, moist air from the room meets glass or frames colder than its dew point. Common causes are high humidity from cooking and drying clothes, too little ventilation, older units without Low-E glass, and cold bridging at the kerb or frame. Fixes range from better ventilation and working vents to new glass units and insulating the upstand. A condensation diagnosis visit starts from £145 ex VAT, and the fixed price is confirmed in writing before any work starts.

Yes, swapping the existing units for solar control glass is usually the most practical way to cut heat gain without replacing the lantern. Solar control glass has a lower g-value, so less of the sun's heat comes through, and a working opening vent helps let warm air out. The guide price is £345 to £895 per glass unit ex VAT, with the fixed price confirmed in writing before any work starts. Our guide roof lantern too hot? explains the options.

Most roof lantern leak repairs fall between £195 and £595 ex VAT per lantern, depending on the fault, the size of the lantern and access. As a guide, resealing a standard lantern is £245 to £495, capping repairs are £165 to £395 and upstand repairs are £395 to £1,295, all ex VAT. These are guide ranges, and the fixed price is confirmed in writing before any work starts. Our prices page lists every service, and our guide to roof lantern repair cost explains what drives the figure.

Reviewing your photos and giving a guide price is free, while a diagnostic visit is charged from £145 ex VAT. Send photos of the lantern inside and out by WhatsApp or through our quote form and we will tell you what we think is wrong. If the cause is not clear from photos, a leak investigation visit includes an inspection, water testing where needed and a written report. The fixed price is confirmed in writing before any work starts.

The price is fixed and confirmed in writing before any work starts. After reviewing photos or visiting, we send a written quote that sets out the work, the materials, any access equipment and the total, with VAT shown separately. Nothing goes ahead until you have accepted it. If we find something unexpected once work begins, we stop and explain it, and any extra work is only carried out once you have agreed a new written price.

Prices on this site are shown ex VAT, so VAT at 20% is added for customers who pay it. For example, a guide price of £245 ex VAT is £294 including VAT. Your written quote shows the price before VAT, the VAT and the total, so you can see exactly what you will pay. The fixed price is confirmed in writing before any work starts.

The main things that affect the price are the type of fault, the size and material of the lantern, the glass specification and how we can safely reach it. A single-storey lantern with ladder access costs less than one that needs a tower or scaffold, which adds a guide £245 to £895 ex VAT. Bespoke glass, timber repairs and work outside normal hours also add cost. The fixed price is confirmed in writing before any work starts.

Repair is usually much cheaper than replacement, as long as the frame is sound. Most leak repairs are a guide £195 to £595 ex VAT, while a standard-size replacement lantern is a guide £1,995 to £4,995 ex VAT supplied and fitted. Replacement starts to make sense when the frame is rotten, distorted or failing in several places, or when most of the glass units need replacing at once. The fixed price is confirmed in writing before any work starts. See repair or replace a roof lantern?

Yes, a guide price from photos is free and is often enough to show what kind of repair is likely. Send a wide shot of the lantern from outside, close-ups of any damage, photos from inside showing where water or misting appears, and a rough size. Use WhatsApp or our quote form. If photos are not enough, we will suggest a diagnostic visit. The fixed price is confirmed in writing before any work starts.

Yes, we cover the whole of the UK, including England, Wales, Scotland and Northern Ireland. Islands and remote areas are covered by arrangement, and any extra travel or access costs for those are set out in your written quote. Send your postcode with your photos and we will confirm the details. You can also look up your town on our areas page.

Your contract is with S&K Property Investments and Improvement Ltd, registered in England and Wales, company number 16932889. The same company sends your written quote and your invoice, and the work is carried out by repair engineers working for us. If you have a question at any stage, you can reach us through our contact page.

Most single-storey roof lanterns can be reached safely with ladders and roof access, so scaffolding is not usually needed. Where ladder access is not safe, for example on a higher roof, a fragile roof covering or a lantern set well back from the edge, we use a tower, edge protection or scaffold. Access equipment is a guide £245 to £895 ex VAT and is included in your quote, with the fixed price confirmed in writing before any work starts.

Usually yes, briefly, because we need to see where water or misting appears inside and sometimes watch during a water test. Most repair work itself is done from outside on the flat roof. If glass units are being changed, we may need to protect the floor and furniture below. We tell you in advance what access we need and roughly how long we expect to be there, so you can plan around it.

Not always, as long as we can reach the roof safely and you are happy for work to be done from outside. For leak investigations and any work that needs inside access, someone needs to be there to let us in. Landlords and letting agents can arrange for a tenant or key holder to meet us. We agree the arrangements with you before anything is booked.

If water is pouring in or glass is broken, we arrange an urgent make-safe as soon as we can to weatherproof or secure the lantern until the permanent repair. That might mean temporary sheeting, sealing or boarding. A make-safe visit is a guide £195 to £395 ex VAT, and the fixed price is confirmed in writing before any work starts. Meanwhile, keep people clear of the area below. See urgent make-safe.

No, we advise against climbing onto a flat roof to inspect a roof lantern yourself. Flat roof coverings can be slippery or fragile, roof edges are often unprotected, and the glass is not designed to be leaned or stood on. Photos taken from an upstairs window, the garden or inside the room are usually enough for a first review. Gutter clearing and seal checks are part of a maintenance visit.

Start by sending photos and your postcode by WhatsApp or through our quote form. We review them, give a guide price and, if needed, suggest a diagnostic visit. Once you accept the written quote, we agree a date for the work with you. The fixed price is confirmed in writing before any work starts, and nothing is booked without your agreement.

Like-for-like repairs such as resealing, new cappings, gaskets or a replacement glass unit do not usually need building regulations approval. Replacing a whole lantern usually counts as building work and must meet the rules where you live: the Building Regulations 2010 in England, the same regulations as applied in Wales, the Building (Scotland) Regulations 2004 in Scotland, and the Building Regulations (Northern Ireland) 2012 in Northern Ireland. Our building regulations guide covers each nation.

Replacement is usually worth considering when the frame itself is failing, not just the seals or glass. Signs include widespread rot in a timber lantern, a distorted or sagging frame, most of the glass units failing at once, or repeated leaks from different places after earlier repairs. A standard-size replacement is a guide £1,995 to £4,995 ex VAT supplied and fitted, with the fixed price confirmed in writing before any work starts.

It might, so check your installer's or manufacturer's warranty before any repair. If your lantern or extension is still in warranty, contact the original installer first, as many warranties require them to carry out or approve repairs. If the warranty has expired, or the original installer cannot help, send us photos and we can quote. We set out the proposed work in writing so you can check it against any warranty terms.

In most cases, yes, we can match replacement cappings, trims and touch-ups to your existing colour, ideally from its RAL number. If you do not know it, we compare against a colour chart on site. Aluminium and uPVC parts weather over time, so a new part can look slightly different from older ones next to it. If the finish is tired overall, respraying the lantern to a RAL colour gives an even finish.

Most roof lanterns benefit from a check and clean once or twice a year, ideally including one visit after autumn leaf fall. A maintenance visit covers cleaning the glass and frames, clearing the eaves gutter and weep slots, checking seals, cappings and the flat roof junction, and testing any vents. It is a guide £95 to £245 ex VAT per visit, with the fixed price confirmed in writing before any work starts. See our maintenance checklist.

Yes, we repair aluminium, uPVC-capped and timber roof lanterns whoever made or installed them. We are an independent repair service and are not tied to any manufacturer. Some parts, such as cappings and ridge end caps, are specific to one system, so we identify the make from photos where we can and source compatible parts. See aluminium, uPVC and timber lantern repairs.

Check with your local planning authority before changing the look, materials or glass of a roof lantern on a listed building, because listed building consent may be needed even for some repairs. Conservation areas can also have their own restrictions. Like-for-like repairs that do not change the appearance are less likely to need consent, but the council's conservation officer is the right person to confirm. We can provide a written description of the proposed work to help.

Regular maintenance is the most practical way to reduce the chance of future leaks. Keep the eaves gutter and weep slots clear, look for lifted or cracked cappings and seals, check the flat roof junction after storms, and deal with small faults before they spread. No repair stops a lantern ageing, but problems found early are usually cheaper to fix. Ask about a maintenance visit.