Skylights, spotlights and light in a solid conservatory roof

Swapping a glass or polycarbonate roof for a solid one takes away the light that came through the old roof, and the room behind the conservatory can feel it most. You can put much of it back with roof windows, glazed panels or a lantern, and light the evenings with spotlights set into the new plastered ceiling. Each option costs extra, loses a little more heat than solid roof, and comes with rules on U-values and electrical sign-off.

This guide compares the options, what they cost and what to settle before the roof is ordered, because roof windows, glazed panels and lighting cables all go in during the build, before the ceiling is plastered.

Does a tiled conservatory roof make it darker?

Yes. A solid roof removes the light that came through the old glass or polycarbonate, and MoneySavingExpert posters warn that rooms behind the conservatory can become noticeably darker. Light still comes through the side windows and doors, and installers point out that roof windows, glazed panels or recessed lights can offset the loss.

The rooms that suffer are the ones that borrow light: a kitchen or dining room whose only window or patio door opens into the conservatory. If that describes your house, plan glazing over the doorway, or consider a hybrid roof rather than an all-tiled one.

Four ways to keep daylight with a warm roof

Option	What it is	Examples from the makers	Typical price in guides
Roof windows	Opening or fixed windows set into the tiled slope	Guardian (VELUX and its own Solstice rooflight), Eurocell Equinox (manual or electric centre-pivot), Warmer Roof (Keylite), Prefix (VELUX pre-fitted in the factory)	About £450 to £2,000 per window
Glazed panels (hybrid roof)	Glass panels in place of some solid sections	Ultraframe LivinRoof and Ultraroof, SupaLite SkyVista, Leka Skylite, Equinox Vega	About £500 per panel in one guide; LivinRoof says panels can be swapped in “without additional cost”
Lantern with a flat roof (orangery style)	A flat insulated perimeter around a glazed lantern	Guardian, Ultraframe Ultrasky, SupaLite ILite with the S1 lantern, Leka	£800 to £3,000 for the lantern alone; a full orangery conversion typically £14,000 to £35,000
Keep a glass roof, upgrade the glass	Performance glass instead of a solid roof	Ultraframe, Pilkington, Saint-Gobain and others	A glass roof typically £3,500 to £7,000

Prices are from ExpertSure, MyJobQuote, Green and Heritage and Best Builders, with our medium conservatory ranges for whole roofs. Installers usually quote including VAT, but check.

Roof windows in a tiled conservatory roof

Roof windows are the simplest way to put light into a tiled slope, and most systems offer them. Price guides put them at about £450 each at the low end (Green and Heritage) and £800 to £2,000 per window at the high end (ExpertSure), with Best Builders adding £500 per roof window to its estimates. On the MoneySavingExpert forum, some owners recommended roof windows for the extra light; others advised against them because of the cost.

Check the pitch first. Guardian’s brochure says its roof windows need a pitch of 15° or more, which can rule them out on a shallow lean-to. SupaLite’s guide tiles around roof windows using a flashing kit.

Roof windows must also meet the energy rules for a new solid roof:

Nation	Roof window	Rooflight	The solid roof around it
England	1.4, or Window Energy Rating Band B	2.2	0.15
Wales	1.4, or Window Energy Rating Band B	2.2	0.13
Scotland	1.4	2.1	0.12
Northern Ireland	1.6, or Window Energy Rating Band C	1.6, or Band C	0.16 to 0.18

The gap is large: a roof window at 1.4 lets through more than nine times the heat per square metre of a roof at 0.15. That is why a few well-placed windows usually make more sense than many.

Glazed panels and hybrid roofs

A hybrid roof is a solid insulated roof with glass panels in chosen places. Ultraframe says LivinRoof glass panels can replace any of the solid panels “in almost any shape”, at pitches from 5° to 40.9°. SupaLite’s SkyVista panels are solar control, self-cleaning glass, and SupaLite says they reflect up to 60% of solar heat with up to 47% light transmission. SkyVista Glow adds heated glass, which SupaLite says costs about 9p per hour per panel at 25p per kWh.

On a medium conservatory a hybrid roof typically costs £6,600 to £12,600 fitted, against £7,400 to £12,100 for an all-tiled roof; see our hybrid roof costs. Solar control glass adds £100 to £180 per panel and self-cleaning glass £120 to £200 per panel on a LivinRoof, according to ExpertSure.

The trade-off is warmth. We estimate a roof that is about 85% solid and 15% glazed at an overall U-value of roughly 0.25 to 0.4, and ExpertSure notes that adding glass reduces the solid roof’s advantage. The glazed areas also let in some summer heat and rain noise. Our tiled vs hybrid comparison and hybrid roofs page go into the choice.

For the glass itself, Ultraframe recommends high light transmission glass for north or east facing rooms and high solar rejection glass for south or west facing ones. Which? says self-cleaning glass needs a pitch of more than 10 degrees to work.

Lanterns and flat rooflights

An orangery-style conversion replaces the pitched roof with an insulated flat perimeter around a glazed lantern, bringing light into the middle of the room. Guardian, Ultraframe, SupaLite and Leka all make flat roof or orangery systems for this. Guardian says building regulations approval is usually required and existing structures may need extra support.

MyJobQuote puts an installed roof lantern at about £2,250 on average, from around £1,000 for a small uPVC lantern. Lantern U-values are far higher than the roof around them: Ultraframe gives a typical whole-lantern figure of 1.4 for a 1m x 2m Ultrasky, and Korniche publishes glass figures of 1.2 standard and 1.0 premium. Raising the roof can also bring planning rules into play, with a 4m height limit for single-storey extensions in England and 3m at the eaves within 2m of a boundary. See orangery conversions for the full picture.

Spotlights and downlights in a solid roof ceiling

Recessed downlights are the usual way to light a solid conservatory ceiling. Price guides put a set at about £300 to £600, with MyJobQuote’s average around £400; one tradesperson quoted £7 to £35 per light plus about £150 to £200 for the work. Best Builders prices an insulated internal pelmet with downlights at £900 as an extra.

The wiring goes in during the build. Guardian’s installation guide says lighting wiring should be added at the first-fix stage, before the insulated plasterboard goes up, and that spotlight holes are cut through the board into pre-cut holes behind it. Ultraframe says the “sandwich” construction of LivinRoof means the correctly rated wiring and light fittings must be used.

The rules apply even though conservatories are often exempt:

• Part P still applies. Electrical safety rules cover a conservatory fed from the house even when the rest of the building regulations do not.
• Some work must be notified. Installing a new circuit, replacing the consumer unit, or altering circuits in special locations is notifiable.
• Certification and the vapour barrier. LABC asks for certification to BS 7671 for lighting in the roof, and for building control to check that the insulation and vapour barrier have not been compromised.
• Use a registered electrician. Electricians registered with schemes such as NICEIC (Certsure), NAPIT, BESCA, Blue Flame or OFTEC can self-certify. Keep the certificate: LABC says building control does not hold copies.

Do skylights change the building regulations?

No. A solid roof needs building regulations approval with or without skylights. What glazing can change is whether the building still counts as a conservatory. In England there is no fixed percentage: a conservatory stops being exempt when the roof glazing is “significantly” reduced, so a hybrid is judged the same way as a solid roof.

Scotland and Northern Ireland define a conservatory as having at least 75% of its roof translucent (or 95% under Scotland’s alternative test), so a hybrid with half its roof glazed would not count as one there.

If you also plan to remove the doors between the house and the conservatory, the rules tighten. The LivinRoof certificate, for example, then limits roof glazing to under 25% of the floor area at a U-value of 1.6. Our building regulations guide covers thermal separation.

Plan the light before you order

When you get quotes, settle these points with each installer before the roof is ordered, while the design can still change:

• Which rooms borrow light through the conservatory, and where glazing would help them most.
• The number, size and position of roof windows or glazed panels, and the U-value and glass type for each.
• Whether the roof pitch suits the roof windows you want.
• How many spotlights, where the switches go, who does the electrics and who issues the certificate.
• How the lights and any cables keep the vapour control layer intact.
• Blinds for roof windows or panels in a south-facing roof, if glare is likely to be an issue.