Most people ask the same two things before a conservatory roof goes ahead: what exactly will happen, and for how long will the room be unusable. The honest answer to the second is that it depends on the roof. A compact lean-to under a light covering is a shorter job than a large P-shaped room with a tiled solid roof, and weather plays its part on any exposed stage. We do not quote a fixed number of days in a guide, because a number that suits one room misleads about another. What we can do is lay out the stages in order, say what each involves and show where the room is affected, so you can plan around it. The programme for your own roof is confirmed in writing alongside the fixed price. Think of the work in two halves. Before anyone arrives with tools, there is a stretch of surveying, design and paperwork. Then comes the work on site, which is the part most people picture.
Before the work: survey, design and paperwork
The first stage happens without any scaffold in the garden. We visit, go up onto the roof and look at the covering, the roof bars, the frame, the walls and the abutment with the house. We take pictures of what is there so that the written scope refers to your own conservatory and not a generic one. This is also when the structure gets its first look, because the choice of covering depends on what the frame can carry. Our guide to checking the frame, walls and foundations explains what we are looking for.
Once the visit is done, the price arrives in writing and stays fixed, with each item of scope listed. For a solid roof the next step is the paperwork. Solid roofs trigger a Building Regulations application, and the form-filling on notifiable work is ours. A protected house, whether listed or inside the conservation boundary, may need a consent first, and we explain the order of events in our guide on listed and conservation-area homes. Approval times belong to the council or the approver, not to us, so we do not promise any.
Materials come next. Standard glazing units, tiles and roof bars may be available quickly, but anything made to measure, such as glass for an unusual shape, takes time to produce. That wait is usually the longest gap in the whole project, and it happens before the room is touched. Keep using the conservatory as normal until a start date is agreed.
Finally, we agree the practical details with you: where materials can be stored, where the skip or waste bags go, how we reach the garden, and whether any neighbour needs a word about scaffold or noise. Fifteen minutes spent on these saves a bad morning later.
The day the work starts: preparing the room
The room is emptied before we begin. Furniture, plants, rugs, curtains and anything fragile come out, because dust and debris from a roof strip are hard to avoid, and a conservatory is rarely sealed from the house. Where there is a door between the two rooms, we keep it shut and protect the floor along the route we use. If you can leave the conservatory empty for the duration, the job runs more smoothly.
Electrics and heating deserve a thought. Many conservatories have sockets, lights or a radiator that connects to the house. Lights and sockets on a roof-mounted circuit need isolating, and any pipework fixed to the frame needs protection or moving. If you have a fan, a heater or a blind motor fixed to the old roof, tell us at the survey so that it is listed in the scope.
Access and protection come next. A conservatory roof is often low enough to reach with a tower or a ladder platform, though a tall or awkward one may need scaffold. Either way, the working area is set up so that the garden, the paving and the house wall are covered where needed. On a terraced Bath house, the route through the property or along a side passage determines how materials get to the back. We look at that route at the survey and make a plan, because it affects both the cost and the working day.
This preparation takes a short part of the first day. It is routine and unglamorous, and it is the reason the later stages go without damage to the room you want to keep.
Stripping the old roof
The old covering comes off in a set order. For polycarbonate, the sheets are unscrewed or released from their glazing bars, lowered and bagged. For old glass, the units are taken out one at a time by two people, since sealed units are heavy and awkward. Cappings, gaskets and trims go next, and then the roof bars themselves if they are to be replaced. All of it is taken away at the end, so you are not left with a skip full of glass in the garden.
The roof is kept watertight as far as possible while it is open. If the work stretches over more than a day, the structure is covered at the end of each session. That is a standard part of the plan, not a favour, but weather can still interrupt the programme. If heavy rain is forecast for a stage that leaves the room open, we reschedule it, since a wet conservatory floor helps nobody.
Stripping also gives the first clear view of the bare frame and where the roof abuts the house. Hidden problems show up at this point: a rotten timber plate, a corroded bar end, a cracked piece of stone or mortar at the wall, or a flashing that let water in long before you noticed. The scope allows for the ones we can reasonably expect from the survey. If something unforeseen turns up, we stop, show you what we found and tell you what it means for the job and the price before anything extra is done.
A roof strip is the moment when the survey is checked against reality. Expect a call or a conversation on the day if something differs from what we saw from outside.
Structure and preparation
With the old roof gone, the work moves to the structure. This stage varies the most from job to job, and it is the stage a heavier roof makes more demanding.
For a solid roof, any strengthening agreed in the survey goes in now. That might be a new eaves beam, a continuous wall plate to spread the load or reinforced posts. The plate is levelled and fixed, and the tops of the walls are checked for level. If building control has asked to inspect the structure before it is covered, this is the moment, so we arrange the timing with them in advance and hold the work until they have seen it. Inspection requirements are set by the building control body, and we ask what they need when the application goes in.
For a glass or lightweight roof, the preparation is shorter. The frame is checked for square and level, the bearing surfaces are cleaned and the new roof bars are set out. Getting this right matters, because a glazing unit that does not seat on a flat, even bar will leak, however good the glass is.
At the house wall, the junction is prepared for the new flashing. On a stone house, we work with the mortar as it is, repointing in a suitable mix if joints need attention instead of forcing cement into old stone. Our page on insulating a conservatory roof explains what goes into a warm roof, and the structure has to be ready for that build-up before it begins.
This is also the stage where the room is most exposed. Good planning makes it short, and it is why we prefer to have materials on site before the old roof comes off.
Fitting the new roof
Now the new roof goes on. The sequence depends on the type, and here it is for each.
Solid roof
A solid roof is built up in layers. Rafters or a lightweight roof structure go on first, followed by insulation between and over them, a breathable underlay (a membrane laid under the battens to shed any water driven past the covering), then battens (thin timber laths that carry the tiles), and finally the tiles themselves. Ridges and verges are formed at the edges and fixed mechanically, since BS 5534:2014 does not rely on mortar alone to hold them. Inside, plasterboard and a skim go up, or a finished ceiling system is fitted.
Glass roof
Glass goes on after the bars. The sealed units are lifted into position, seated on gaskets, and held down by cappings. The ridge and the eaves are sealed, and weep paths for condensation are cleared so any moisture that gets in can drain out. The choices of glass specification are described in our guide to glass replacements.
Lightweight panels
Where the roof is a lightweight insulated system, the panels are fixed in sequence and sealed at each joint. They are quicker to fit than a tiled roof, but the same attention to flashings applies.
In every case the roof is made watertight as early as possible, and the fitting order, ridge first or one side across, follows the design. The room is usually out of use through the main fitting stage, and for a solid roof the interior finishing keeps it out of use a little longer.
Flashings, finishing and handover
The last stages are the ones that make a roof last. The flashing, a strip of lead or a similar material dressed over the joint with the house wall, is fitted and tucked into the masonry. On stone, it is wedged into a joint and pointed in rather than being surface-fixed with sealant. Gutters and downpipes are connected so that the new roof drains cleanly, and any trims, vents or cappings are finished.
Inside, the finishing depends on the roof type. A solid roof has plastering or a board finish, plus spotlights or a ceiling fan if they were in the scope, and decoration is usually left to you unless it was agreed. A glass roof is cleaned inside and out, blinds are refitted if you have them, and the seals are checked once more.
We then clear the site. Waste is taken away, the garden and paths are swept, and the room is left ready for your furniture to go back. Before we go, we walk through the work with you, show you the details and answer questions. A final set of pictures goes into the record.
Paperwork follows. Where building control is involved, ask what inspections and sign-off they require, and keep whatever they issue with your house papers. Keep any manufacturer's warranty on the roof panels or glazing with those papers too, and note the date the work was finished, since warranties usually run from that day.
Finally, consider insurance. Telling your insurer about the change is sensible, as a new roof can alter the cover. Our guide to conservatory roof insurance explains what to ask. For the overall service, see conservatory roof replacement.