Conservatory roof replacement in Stroud

Conservatories put up before solid-roof kits became common were generally roofed in one of two ways: multiwall polycarbonate sheet or double-glazed glass units. Both are light and both let a lot of sun in. They also grow tired in different ways, and the way yours is tired tells us a good deal about what to do next.

Polycarbonate

Multiwall sheet is a plastic with long hollow channels running down the slope. The sheets sit in aluminium or uPVC glazing bars, sealed with rubber or foam strips, and the open ends of the channels are closed with tape or a profile. Over the years sunlight yellows and clouds the plastic, the end tape lifts, and dirt and algae creep into the channels where no brush can reach them. HomeBuilding put a typical polycarbonate roof life at around 10 years in April 2024, and The Eco Experts quoted about 10 to 15 years for glass or polycarbonate that same month. Those are typical figures, not promises. Shade, orientation and how well the bars were sealed all move them.

Glass

A glass roof is built from sealed double-glazed units. When the seal fails, moisture gets between the panes and the unit mists permanently. One misted unit can be swapped on its own, but several across a roof usually say the gaskets and the bars have aged as well, and replacing units one at a time stops being good value. Glass is also heavier than polycarbonate, which matters later if you are thinking of a solid roof, because the frame was designed around whichever of the two it carried.

What like-for-like involves

Renewing in kind sounds quick, and the work itself is. The care goes into everything around the sheets: the glazing bars, which may be pitted or sagging, the eaves beam they sit on, the cappings at the ridge and the join with the house wall. New sheets in old bars with tired gaskets will leak again within a few seasons, so the quote includes the sealing parts. If the bars are in good order, this is the lowest-cost route.

Noise is the other complaint we hear about thin sheet. Rain on multiwall polycarbonate drums on the plastic and echoes through the room, and a heavier or double-skinned cover softens it. If the drumming is what drives you out of the room, mention it at the survey, because it affects which roof we suggest.

When to change material

If the complaint is heat, cold or noise, a fresh sheet of the same material rarely cures it. That is the point at which owners start to look at the alternatives. Our guide to glass, polycarbonate or tiled conservatory roofs sets the three side by side.

Between a plain polycarbonate roof and a fully built tiled one sits a family of lightweight tiled systems. They are supplied as engineered kits, with structural panels or rafters, an insulated build-up and a tile-effect or real tile covering, designed so the whole roof weighs less than a conventional tiled roof on timber. The pitch of the claim is simple: you get a solid, insulated roof without asking the old frame to carry what a traditional tiled roof would.

Read the data sheet

Every system comes with its own data sheet, and that sheet is the authority on three things. The first is weight per square metre, which you compare with the sheets or glass coming off. The second is the minimum roof pitch, which is a product limit rather than a general rule; manufacturers publish different minimums for different covers, and a conservatory roof is often shallower than a house roof. The third is how far the kit can span between supports before it needs a steel beam or a ridge. We take the data sheet to the survey, not the other way round.

Measuring before choosing

Because pitch is the first limit, we measure the existing rafter pitch and the span from the house wall to the eaves before suggesting any system. A conservatory with a gently sloping lean-to roof may rule out a tiled kit altogether, or need the kit set on a built-up deck. That is better to find out on the survey than after the delivery has arrived.

Ridge and edges

Where a system uses ridge, hip or verge fittings, BS 5534 expects them to be fixed mechanically, because mortar by itself cannot be depended on to hold them down. Dry-fix products, which are tested under BS 8612, do that job without a mortar bed. We leave the choice to the system's own instructions and fit exactly what the manufacturer specifies.

Looks from the garden

A lightweight tiled roof lives in plain sight, next to the house roof, and the match is judged from the lawn. Colour, profile and the line where tiles finish against the house wall all count. Where the house is old, a plain tile or a slate-effect finish tends to sit better than a bright modern colour. Matching the house roof is a question of colour, profile and size of tile.

Fixing and weathering

The cover on a kit is only as good as what holds it. We fit the system exactly as its instructions say, with the specified battens, fixings and underlay, and we weather every edge before the day ends. A kit left half-fitted overnight is a leak waiting to happen, so we plan each stage to finish closed in.

Renewing polycarbonate with polycarbonate, or glass with glass, is ordinary maintenance. The moment the roof becomes solid, the position changes. Homebuilding, updating its guide in July 2023, states that swapping a conservatory roof structure for a solid one is material alteration work covered by the Building Regulations, so you submit a building control application and an inspector checks the work.

Who deals with it

In Stroud District, building control is run by the Gloucestershire Building Control Partnership, shared with Gloucester City. Across the border in Cheltenham and Tewkesbury it is Cheltenham and Tewkesbury Building Control, and the Forest of Dean District Council runs its own. A registered building control approver is the private alternative anywhere in England. If the work is notifiable, we explain what building control needs, make the notification ourselves and hand you the completion paperwork when it is signed off.

What the inspector looks for

The Planning Portal puts it plainly: a new roof must comply with the Building Regulations so that it is structurally safe, energy efficient and properly ventilated. That covers the frame check from the previous chapter, the insulation level, and the ventilation of the roof build-up. If you add a rooflight, Approved Document L sets a limit of 2.2 W/(m²·K) for rooflights, a figure to compare when choosing between products. Our page on roof windows and rooflights covers the glazing side.

Planning permission

The Planning Portal adds that if a change significantly alters the structure or appearance of the roof, planning permission may be required. A solid roof on the same footprint, with a similar height and no extra windows, is a modest change, but a taller lantern or a new roof pitch moves it into territory where a call to the council is sensible.

Listed houses and conservation areas

Stroud District has 41 conservation areas, and five carry Article 4 Directions, among them Bisley, both Stroud areas and Wotton Under Edge. The council's page leaves open whether roofs fall under them, which is a question for its planning team. A conservatory attached to a listed house is the sort of structure where the council advises checking its status with the conservation department. Listed building consent is a legal requirement for works that affect a listed building's character.