Conservation Rooflights: What Councils Require (Local Guidance Compared)

Three small conservation rooflights in the slate roof of a two-storey Bath stone cottage, painted rainwater goods at the eaves

Planning authorities publish their own rules on rooflights, and they differ in the detail. This chapter brings together the written guidance of more than twenty councils and national park authorities across England, Wales and Scotland, with links to every source document, so you can see what your officer is likely to expect before you draw […]

How Much Does a Conservation Rooflight Cost? Prices and Budgeting

Close view of a three-bay conservation rooflight with black frames and narrow glazing bars sitting low in a slate roof

What a conservation rooflight actually costs once the unit, the opener, the flashings, the fitting and the consent are added up. Prices are taken from manufacturers’ and stockists’ published figures in October 2026 and will change; treat them as a guide for budgeting, not a quotation. In summary In October 2026, a standard-size steel conservation […]

Conservation Rooflights for Slate, Tile, Pantile and Stone Roofs

Detail of two conservation rooflight frames close to a ridge, showing the glazing, frame edge and the slate and lead junction

A conservation rooflight only looks right if it sits properly in the roof covering around it. This chapter takes each common historic roof covering in turn: natural slate, plain clay tile, pantile, stone slate and metal, and sets out what changes for each. In summary The roof covering decides how flush a conservation rooflight can […]

Original Cast Iron Rooflights: Identifying, Repairing and Replacing Them

Conservation rooflight with glazing bars set into the weathered slate roof of a historic stable block below a clay-tile ridge

Every conservation rooflight on the market is a copy of the Victorian cast iron original. This chapter is about the originals themselves: how to recognise one, how to repair it, and how to make the case when it genuinely has to be replaced. In summary An original cast iron rooflight is a small, top-hung, single-glazed […]

Daylight Design with Conservation Rooflights: How Many, How Big and Where

Even daylight from a line of three small conservation rooflights high on the north slope of a converted stone barn

A rooflight admits two to three times the daylight of a vertical window of the same size, which is why one well-placed unit can light a room that three windows could not. The right number of rooflights is usually fewer than people first draw, the right size is usually smaller, and the right place is […]

Condensation on Conservation Rooflights: Causes, Cures and What Is Not a Leak

Brass screw-jack winder fixed to the frame of a rooflight fitted with a pleated blind, seen from inside

Water on the inside of a rooflight is the commonest complaint after installation, and most of it is not a leak. Condensation forms on a rooflight because it is the coldest surface at the highest point of a room, exactly where warm, moist air collects; the cure is to reduce the moisture, move the air […]

Fixed or Opening Rooflights? Ventilation, Escape Windows and Controls

Interior with exposed oak beams and two opening rooflights with top-hung sashes propped open for ventilation

From the outside a fixed and an opening conservation rooflight look the same. Inside, the choice decides whether the room can be aired, whether it counts as an escape route, and what the unit costs to buy and look after. Choose a fixed rooflight where the room already has good ventilation and the rooflight is […]

Rooflight U-values and g-values Explained: How to Read Thermal Performance Figures

Cutaway illustration of a conservation rooflight showing the metal frame, glazing bar, double-glazed unit and timber lining

Two conservation rooflights with the same glass can be quoted with U-values half a point apart, and both figures can be honest. A rooflight U-value only means something when you know whether it is a centre-pane or whole-unit figure, what size it was assessed at, and at what angle. This chapter explains the numbers, the […]

Building Regulations for Conservation Rooflights: Parts A, B, F, K, L and O Explained

Large run of linked conservation rooflights in a pitched roof, seen from inside a coastal house with rooftops beyond

Planning permission and listed building consent decide whether a rooflight may go in. The Building Regulations decide how. Almost every new or replacement conservation rooflight in England is controlled work under the Building Regulations, and the parts that matter most are A (structure), B (fire), F (ventilation), K (safety glazing), L (energy) and, for new […]

Rooflights in Barn Conversions: Planning, Placement and Rainwater

Stone barn conversion with a clay-tiled roof and a single linked conservation rooflight, black rainwater goods and a lawn in front

A barn roof is often the building’s most important feature: a long, quiet plane of slate, stone or tile with almost nothing breaking it. Rooflights can bring light into a converted barn without destroying that character, but only if you keep them few, small and well placed. This chapter covers where they go, which permissions […]

Conservation Rooflight Glossary: The Terms Architects, Conservation Officers and Roofers Use

Close-up of a linked conservation rooflight in a slate roof below a clay ridge, with one top-hung sash partly open

Several trades discuss a rooflight on a historic roof, each with its own vocabulary. This glossary sets out conservation rooflight terminology in plain English, so that drawings, consent applications and site conversations mean the same thing to everyone. In summary Conservation rooflight terminology covers five areas: the unit itself, its glazing and performance, the roof […]

Rooflights, Roof Works and Rainwater Goods: Planning One Scaffold

Scaffolded slate roof on a stone building with a slim black steel conservation rooflight and black cast iron gutters at the eaves

Rooflights are rarely the only work a traditional roof needs. If you are replacing gutters when installing rooflights, or even just inspecting them, the cheapest and least disruptive way to do it is under the same scaffold, in the same consent package and on one programme. This chapter explains how to plan rooflight work and […]

Conservation Rooflight Maintenance: A Practical Care Guide for Steel Rooflights

Linked conservation rooflight in a slate roof with its end sash slightly open and glazing bars over each pane

A conservation rooflight is a small steel window set into one of the most exposed parts of the building. Conservation rooflight maintenance comes down to three things: keep the coating intact, keep water moving off and around the frame, and write down what you did. Done twice a year, it takes less than an hour […]

Choosing a Heritage Rooflight: Materials, Sightlines and Thermal Performance Compared

Close view of a three-bay conservation rooflight with black frames and narrow glazing bars sitting low in a slate roof

Steel or aluminium-clad timber. Structural glazing bar or applied. Whole-unit U-value or centre-pane. A technical comparison of how heritage rooflights differ, and which differences a conservation officer will actually see. In summary Heritage rooflights divide into two broad constructions: purpose-made steel conservation rooflights, and volume roof windows with a timber core and aluminium cladding configured […]

Conservation Rooflights for Listed Buildings: The Complete Specification Guide

Three-bay linked conservation rooflight with slim glazing bars, fitted flush in a Devon slate roof with one sash open

A conservation rooflight is not simply a small window in a roof. It is a piece of historically informed detailing that has to satisfy a conservation officer, a building control officer and the weather at the same time. This guide sets out how we specify them, and where specifications most often go wrong. In summary […]