Robby Branson
A Professional You Can Trust.
Robby Branson Builders Ltd
A Professional You Can Trust.
Robby Branson Builders Ltd
Windows and doors are the second most popular upgrade when it comes to conservatories—and with good reason. To be officially classed as a conservatory and take full advantage of permitted development rules (including avoiding the need for full building regulations), your structure supposed to have at least 50% glazed walls and 75% glazed roof area.
No one typically comes out with a tape measure to check exact percentages, but we have seen cases where a neighbour, unaware of the rules, contacted the local council assuming a full extension was being built. So, to avoid unnecessary hassle, we always recommend letting your neighbours know in advance—even if relations aren’t great. A simple note through the door can prevent surprises.
The range and types of windows and doors on the market today is vast, and understanding some of the technical basics can help you make a more informed decision.
Most people start with the roof or the glass, but in reality the doors are one of the most important decisions you’ll make. They determine:
how you access the garden
how the space flows
how much ventilation you get
how warm the room feels in winter
where your windows and frames will fall
whether extra structural support is needed
This is why we always decide the door type and position first. Once that is set, arranging your window layout becomes far easier and far more logical.
Simple, reliable, and ideal when you need a basic access point — for example, a side door leading to a path, bins, garage or utility area. They take up very little space and rarely need any special engineering.
Best for:
Small conservatories
Side access
Keeping costs down
While not traditionally associated with rear conservatories, panel doors and composite doors are still a valid option in certain situations. They are especially useful where the conservatory acts as a front entrance, side porch, or additional lobby area.
These doors offer:
higher security (multi-point locking as standard)
better insulation than glazed doors
a more “house-door” appearance
low maintenance (especially composite types)
Best for:
front or side porches
utility/boot room conservatories
customers wanting the appearance of a standard home entrance
situations where privacy is preferred over full glazing
They don’t give the open, airy feel that glazed doors provide, which is why you see them less often on garden-facing conservatories — but where security, privacy, or insulation is the priority, they are an excellent choice.
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Still one of the most popular choices. French doors normally go up to around 1.8m wide before side lights are required. They give a nice opening, good airflow, and a clean, traditional look.
Best for:
Most standard conservatory layouts
Balanced ventilation
Easy access
Medium budgets
A good option when you want wider glass but don’t have the space for doors to swing open. They slide neatly, offer good views, and suit longer walls.
Best for:
Wider openings
Limited inside/outside space
Modern or minimalistic designs
These are the “open everything up” choice that many homeowners love. They fold neatly to one side and create a fantastic indoor–outdoor feel in summer.
But — and this is where most sales companies stay quiet — bi-folds need more engineering than other doors.
Conservatories were never originally designed for big, wide openings, and once you go beyond a normal French-door span the standard frames and roof bars cannot safely carry the load.
That’s why several manufacturers now offer proprietary reinforced beam systems specifically designed for:
carrying the weight of the roof
preventing the opening from spreading over time
keeping the bi-folds running smoothly
avoiding sagging, twisting, or future misalignment
These structural upgrades are not complicated. Many are pre-approved for projects where Building Regulations are required, which means they are perfectly suitable — and often essential — for conservatories where full approval is not needed.
Your door decision affects practically everything that follows:
where window breaks (Structural uprights) sit
how many panes you need
how the roof loads fall
how much furniture space you have inside
whether structural beams are required
Where openings go for cross ventilation
how the garden path routes work
Once the doors are set, designing the windows becomes a simple, clean task — and the whole conservatory functions better because of it.
Glass units for windows and doors can vary slightly from those used in roofing, but the core principle is the same. One key difference is that toughened (tempered) safety glass is only required in certain areas—mainly doors or windows set below 800mm from the finished floor. Self-cleaning glass, while common in conservatory roofs, is rarely used in the side glazing unless requested.
Double-glazed units are rated as a complete unit, not by the individual panes. The British Fenestration Rating Council (BFRC) grades thermal performance from G (worst) to A++ (best), similar to how appliances are rated. So, when someone says a window is “A-rated,” it means it has excellent thermal efficiency overall—not just good glass.
Improvements in frame design have increased energy efficiency across all materials, though the effect on total heat loss is modest compared to the large glazed areas in conservatories.
1: uPVC (PVCu) frames are typically the most thermally efficient due to how they’re extruded during manufacture. Many achieve U-values around 1.2 or better and are fully recyclable.
2: Timber frames can match these figures, but only the higher-end, engineered timber models reach similar thermal performance. Standard timber frames are often closer to 1.6 U-value, unless you invest in multi-layer hardwood constructions.
3: Aluminium frames, once poor performers, have now caught up thanks to thermal break technology—but U-values still vary widely between manufacturers, so it’s important to check specs carefully.
4: Hybrid frames, like those from Andersen (a high-end American manufacturer we’ve worked with), combine the warmth of timber with the durability of aluminium cladding. These are premium products with a long lifespan.
By following the link below, you’ll be taken to our Glass and Glazing page, where you’ll find clear, detailed information about glass options for windows, doors and roofs.
When you think about how much surface area the glass covers in a conservatory, it’s easy to see why it plays the biggest role in overall performance. The frames of course matter too — mainly for appearance, long-term serviceability and strength — but it’s the glass that does most of the heavy lifting in keeping the room comfortable.
uPVC frames are by far the most popular option when it come to windows and most doors because the hit the minimum requirements or better for the current thermal regulations, they are easy to service and there are options for all budgets.
Colour is the first thing after your frame is chosen, white is by far the most common and for more than one reason.
When you add in the reckoning that both the uPVC and the metal hardware are both recyclable it gives another level of benefit in todays environmental aware world.
There are differences in quality with different manufacturers and we will explains some of those here as it can substantially affect costs.
Simply drop us an email at robbyuk2010@gmail.com and you’ll receive a reply normally within 24 hours