Hybrid conservatory roofs

A hybrid roof answers the main complaint about solid roofs: that they make the conservatory, and the room behind it, darker. Most of the roof is insulated and solid, like a tiled roof, and a share of it is glass, either as glazed panels or roof windows. You give up a little of the warmth and quiet of a fully solid roof and get daylight exactly where you choose.

In England, building control asks whether the glazing in the roof has been significantly reduced, and many building control bodies use a benchmark of three quarters of the roof being glazed, so assume a hybrid needs approval like any solid roof. In Scotland and Northern Ireland the rules put a hard figure on it: a conservatory must have at least three quarters of its roof translucent, so a hybrid with, say, half its roof glazed no longer counts as one.

Two ways makers build a hybrid roof

Panel roofs on a glazed-roof frame

Ultraframe’s LivinRoof is built on the same chassis as its glass roof, with thermally broken rafters. Outside, 25mm grey insulated panels (aluminium-faced or composite) sit where the glass would be. Inside, two layers of insulation board, 90mm plus 25mm, are fixed on a steel ladder system and finished with plasterboard and a skim, with an insulated plastered pelmet around the edge for lighting.

Because every bay is a panel, glass can replace any of the solid panels, including triangular ones, and Ultraframe says this costs no extra. It quotes 31kg/m² including the plasterboard and pitches from 5 to 40.9 degrees. The look outside is flat grey panels, not tiles, which may or may not suit your house.

Tiled roofs with glass set in

The other route is a normal tiled warm roof with glazed units built into it:

• SupaLite with SkyVista: one or two solar control, self-cleaning glass panels in a SupaLite tiled roof, for Edwardian, Victorian and lean-to shapes. SupaLite quotes up to 60% solar heat reflection and up to 47% light transmission. SkyVista Glow adds thermostatically controlled heated glass, which SupaLite puts at about 9p an hour per panel at 25p/kWh.
• Prefix WARMroof Hybrid: 28mm double glazed panels as standard, 44mm triple glazing as an option, in variable positions.
• Icotherm IcoView: fixed glass pods in single, double or triple runs, up to 800mm wide. Icotherm describes it as only marginally heavier than a glass roof.
• UltraRoof 380: full-length rectangular glass panels in any specification, including solar control, or Velux-style roof windows.
• Guardian and Equinox: roof windows (Guardian’s own Solstice rooflight and VELUX; Equinox’s centre-pivot windows) plus, on Equinox, the fully glazed Vega panel.

How much glass is too much?

Every square metre of glass swaps an insulated section for one that loses heat several times faster. The figures you will see:

Few makers publish a whole-roof figure once glass is added, so ask the installer to calculate one for your design. A roof that is mostly solid with a few well-placed panels keeps most of the benefit. Once glass reaches a large share of the roof, you are close to paying solid-roof prices for glass-roof comfort, and a solar control glass roof may be the better buy.

Where to put the glass

Think about where the room is darkest and which room behind borrows its light. Common layouts:

• a line of glass along the house wall, where a lean-to is usually darkest and where the room behind gets its light;
• glass over the bay facets of a Victorian, with solid tiles over the rest;
• glass over a dining table or seating area, with the solid areas over a TV or desk, where glare is a nuisance.

Glass that faces south or west needs solar control, and opening roof windows let hot air escape in summer. Plan the ceiling lights at the same time, since the solid sections still need spotlights for winter evenings. Our guide to skylights and lighting in a solid roof covers the options.

Who a hybrid suits, and who it does not

A hybrid suits you if you want a room warm enough for every month of the year but dread a dark room, or if the room behind the conservatory relies on it for light.

It suits less well if budget is the main concern. A medium hybrid typically costs £6,600 to £12,600, much the same band as a tiled roof, but on the same system each glazed panel adds to the price. It is also more to maintain, since every glazed panel has seals and flashings. Trustpilot reviewers of LivinRoof describe intermittent leaks that took several service visits to resolve, and ExpertSure says its guarantee is not insurance backed, so check how glazed panels are sealed and who stands behind the work. We compare the two directly in tiled vs hybrid.

Questions to ask before you sign

When you get quotes, ask each installer:

1. What share of the roof will be glass, and what is the whole-roof U-value with it included?
2. Which glass is in the panels, and what are its light and solar figures?
3. Do any panels open, and is there a blind option?
4. How are the glazed panels sealed and flashed, and what does the guarantee say about leaks at them?
5. Is the guarantee insurance backed, and is it from the maker, the installer or both?
6. Who applies for building control, and will I get the completion certificate?

The hybrid roof cost guide shows typical prices by size and shape.