How to Build a Conservatory? A Guide for Homeowners

Table of Contents

1. Do You Need Planning Permission for a Conservatory?
2. Do You Need Building Regs for a Conservatory?
3. How to Build a Conservatory: Step by Step
4. Choosing Your Conservatory Style
5. How to Build a Conservatory on a Budget
6. DIY Conservatory Kits: Are They Worth It?
7. How to Find a Conservatory Installer
8. FAQs: Building a Conservatory

The planning permission and building regs section affects almost every decision that follows, so it's worth reading that first even if you're keen to get straight to the practical steps.

Do You Need Planning Permission for a Conservatory?

Most conservatories fall under permitted development rights, which means you can build without applying for planning permission - provided you stay within a specific set of limits.

Conservatories are treated more leniently than many other home extensions, but the rules are still precise and worth checking against your specific property before you commit to a design.

You'll generally need planning permission if:

• The conservatory is taller than the highest part of your existing roof
• The eaves or ridge height exceeds your property's existing eaves height
• It sits within 2 metres of a property boundary and the eaves are taller than 3 metres
• It extends more than 3 metres from the rear of a terraced or semi-detached house, or more than 4 metres for a detached property (single storey)
• It covers more than half the total area of land around the original house
• Your property is listed, in a conservation area, or is a flat or maisonette - permitted development rights are significantly more restricted in all of these cases

Even when planning permission isn't required, it's worth applying for a Certificate of Lawful Development from your local council. This isn't compulsory, but it provides documented proof that the structure didn't need permission - useful evidence to have on file if you ever sell the property.

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Do You Need Building Regs for a Conservatory?

This is a separate question from planning permission, and the answer is usually no. But only if your conservatory meets specific exemption criteria.

Most standard conservatories are exempt from building regulations, which is one of the reasons they're a faster and cheaper build than a full extension.

To qualify for the exemption, your conservatory must:

• Be built at ground level and be no larger than 30 square metres in floor area
• Be thermally separated from the main house - meaning there's an external-quality door between the conservatory and the rest of the property, so the conservatory isn't relying on the house's heating system
• Have safety glazing in any glazed areas below 800mm and in doors, in line with general glazing safety standards
• Have its own independent heating system if heated at all, rather than being connected to the main house's central heating
• Not interfere with the building's existing drainage, structural stability, or fire escape routes

If your conservatory doesn't meet these conditions, for example, if you want to remove the dividing door entirely and integrate the space fully into the house, or connect it to the central heating system, it's treated as a standard extension and full building regulations apply, including structural calculations, energy efficiency requirements, and a building control inspection.

This distinction matters enormously for anyone planning to eventually convert a conservatory into a proper room. Building with adequate foundations and structural provision from the start, even if you don't need building regs approval now, makes a future conversion considerably more straightforward.

Worth checking before you start: Even exempt conservatories still need to comply with general building safety, particularly around electrical work. Any electrical installation falls under Building Regulations Part P and must be carried out or signed off by a qualified electrician, regardless of whether the conservatory itself is exempt.

How to Build a Conservatory: Step by Step

The build process follows a fairly consistent sequence regardless of conservatory style. Knowing what happens at each stage helps you understand a builder's timeline and spot where delays typically occur.

Step 1: Foundations and Groundwork

The footing is excavated around the perimeter of where the conservatory will sit, typically to a depth that clears any made-up ground and reaches stable subsoil, often around 1 metre but depending on local ground conditions.

A damp-proof membrane is laid, followed by hardcore and a concrete footing. This stage is also where any drainage or services (for electrics, if planned) get routed before the floor is laid.

Step 2: Dwarf Wall Construction

Most conservatories sit on a low brick or block wall, known as a dwarf wall, typically around 600mm high, though this varies by design and whether full-height glazing is preferred instead.

The wall is built up from the foundation using standard bricklaying methods, with each course checked for level as it progresses. Some modern designs use full-height glazing instead of a dwarf wall, in which case this stage is skipped.

Step 3: External Sills and Frame Installation

Pre-manufactured sills are positioned on top of the dwarf wall, providing the base onto which the frame sections sit. The first frame is fixed and secured to the house wall, and subsequent frames are connected outward from there, working around the perimeter until the structure meets up on both sides.

Getting this stage precisely level and square matters enormously, any inaccuracy here compounds through the roof and glazing stages.

Step 4: Roof Construction

Roof ridge and rafters are fitted to the completed frame structure. The choice of roof type, polycarbonate, glass, or a solid tiled design, is usually decided at the design stage rather than here, since it affects the structural specification of the frame beneath it.

Roofing panels or tiles are then fitted, working from one end to ensure correct overlap and a watertight finish.

Step 5: Doors and Windows

Door and window openings are measured precisely and the units fitted into the prepared frame sections. This stage often reveals any small inaccuracies from earlier in the build, so a degree of on-site adjustment is normal and expected.

Step 6: Guttering and Drainage

Guttering is fitted along the roofline and connected to drainage, directing rainwater away from the structure and the house. This is easy to overlook in planning but matters significantly for the long-term condition of both the conservatory and the wall it's attached to.

Step 7: Internal Finishing

Flooring, electrics (if included), plastering of the dwarf wall if required, and final fittings complete the build. Most of the manufactured components, frames, roof panels, and glazing, are produced off-site in advance, so this final stage is often where any remaining delays are absorbed, since on-site finishing work depends on weather and trade availability rather than factory lead times.

A typical conservatory build takes around 8 to 12 weeks from the point of order, accounting for manufacturing lead time on frames and glazing, though the on-site construction itself is usually completed within a few weeks once materials arrive. See our house extension cost guide for a wider comparison of timelines and costs against a full brick extension.

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Choosing Your Conservatory Style

Style is often the first thing people picture when they think about a conservatory, but it's worth treating as more than a visual preference - the shape you choose dictates the roof structure, the frame specification, and ultimately how much the build costs, so it's worth deciding early rather than midway through getting quotes.

• Lean-to: The simplest and most affordable style, with a single sloping roof running away from the property. Works well on properties with limited height clearance and is the quickest to build of the common styles.

• Victorian: Features a pitched roof and a rounded or polygonal front, typically with an ornate ridge detail. A traditional choice that suits period properties particularly well.

• Edwardian: Similar in structure to a Victorian conservatory but with a square or rectangular front rather than a rounded one. Generally offers more usable floor space for the same footprint.

• Gable-end: A full-height apex roofline that mirrors the gable end of a house, creating a more dramatic, taller structure with a more open feel internally.

• P-shaped: A combination of two conservatory styles joined together, typically used on larger properties where a bigger floor area is wanted, often dividing naturally into two functional zones.

The material - uPVC, timber, aluminium, or brick-based hybrid designs - is a separate decision from the style, and affects both cost and ongoing maintenance.

uPVC is the most budget-friendly and low-maintenance option; timber offers a more traditional appearance but requires more upkeep; aluminium suits modern, slimline frame designs.

How to Build a Conservatory on a Budget

A conservatory is already one of the more affordable ways to add space compared with a full extension, but there are specific decisions that make a genuine difference to the final cost without compromising on a usable, durable result.

• Choose a lean-to design. Of the common conservatory styles, a lean-to requires the simplest roof structure and the least material, making it consistently the cheapest option to build.

• Stick to standard sizes where possible. Bespoke dimensions require custom-manufactured frames and roof sections, which costs more than standard modular sizes that manufacturers produce at scale.

• Choose polycarbonate over glass or tiled roofing. Polycarbonate is the most budget-friendly roofing material, though it performs noticeably worse thermally - worth weighing against how much you plan to use the space year-round.

• Get multiple quotes and compare like for like. Conservatory pricing varies meaningfully between installers for the same specification. Ask each quote to break down materials, labour, and any extras (electrics, flooring, guttering) separately so you're comparing genuinely equivalent offers rather than headline figures that hide different inclusions.

• Time the build outside peak season. Spring and summer are the busiest months for conservatory installers, and pricing and availability can both be more favourable if you're willing to start the project in autumn or winter instead.

• Avoid extras you don't need at the outset. Underfloor heating, premium glazing upgrades, and integrated blinds can all be added later if the budget allows, rather than committing to them in the initial build.

If you're weighing a budget conservatory against starting with a properly specified foundation for a future extension, see our guide on converting a conservatory into an extension for what that decision involves further down the line.

DIY Conservatory Kits: Are They Worth It?

Self-build conservatory kits exist and are genuinely used by a meaningful number of UK homeowners, but they suit a specific set of circumstances rather than being a universal cost-saver.

Kits typically arrive with pre-numbered panels, detailed manuals, and in many cases video walkthroughs covering each stage from groundwork to glazing. A self-build with standard tools and a reasonable level of DIY confidence is usually completed over five to seven days for the structure itself, though this excludes groundworks, which often still benefit from professional input.

• Where DIY kits make sense: smaller, standard-sized lean-to designs on flat, accessible ground, built by someone with genuine prior DIY or construction experience, and where the budget saving justifies the time investment and the risk of needing to correct mistakes.

• Where they don't: larger or non-standard designs, sloping or difficult ground requiring levelling or underpinning, any electrical work (which legally requires a qualified electrician regardless of who builds the structure), and situations where getting the measurements wrong would be costly to fix - which, given that most conservatory components are bespoke-manufactured to the property, is a real risk.

Even with a DIY kit, getting the foundations right is the stage most worth professional input on. A poorly laid foundation undermines everything built on top of it, and unlike the frame and glazing stages, foundation problems are expensive and disruptive to correct after the fact.

How to Find a Conservatory Installer

Talking to professional conservatory installers near you can give a useful benchmark for cost and timescale, and many installers are happy to quote for specific stages - groundwork only, or full installation.

Post your job on MyBuilder with your preferred style, rough size, and budget, and installers in your area will respond with their recommendations and quotes.

All tradespeople on MyBuilder undergo checks at registration, such as ID documents, company details, certifications for regulated jobs and skill assessments, allowing you to hire with confidence.

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FAQs: Building a Conservatory

How Long Does It Take to Build a Conservatory?

Most conservatories take 8 to 12 weeks from order to completion, though this figure is dominated by manufacturing lead time for bespoke frames, glazing, and roofing rather than the on-site build itself.

Once materials arrive, the physical construction, foundations through to finishing, is typically completed within a few weeks, weather and trade availability permitting. You can browse photos of completed conservatory projects on MyBuilder to get a sense of typical timelines from similar jobs.

Can I Build a Conservatory Myself?

Parts of the process are realistic for a confident DIYer, particularly with a self-build kit designed for that purpose, but foundations and any electrical work are the two stages most worth professional input regardless of the rest of the approach.

Getting the groundwork wrong is expensive to correct, and electrical work legally must be carried out or certified by a qualified electrician under Building Regulations Part P.

Does a Conservatory Need a Damp-Proof Course?

Yes. A damp-proof membrane or course is laid as part of the foundation stage, before the dwarf wall is built up. This prevents moisture rising from the ground into the structure above, and skipping this step, even on an exempt, permitted-development conservatory, risks long-term damp problems that are far more costly to fix than to prevent.

What's the Cheapest Type of Conservatory to Build?

A lean-to design in uPVC with a polycarbonate roof is consistently the most budget-friendly combination, owing to the simpler roof structure and lower material cost compared with glass or tiled alternatives. The trade-off is thermal performance, polycarbonate roofs perform noticeably worse in both winter and summer than glass or solid alternatives.

See our conservatory cost guide for a full breakdown of how style and material choices affect overall price.

Do I Need a Structural Engineer to Build a Conservatory?

For a standard conservatory built within permitted development and exempt from building regs, a structural engineer usually isn't required, since installers work to established standard specifications. If you're building on sloping ground, near a boundary, or with the intention of laying foundations that could later support a full extension, a structural engineer's input is worth the cost to avoid expensive problems later.

See our structural survey cost guide for typical fees.