Conservatory Extension

The main reason to convert your conservatory into an extension is that it will give you plenty of extra space.

Keep in mind not to take too much away from your garden but if you have land to the side of your property, this works well with many designs.

Before you start you will need to consider how to use the extra space. More living space, kitchen and bathroom are the best use and easier to blend in to your existing property.

Whether you wish to add a conservatory, a flat roof extension or turn a conservatory into a side extension or orangery, you can apply under permitted development provided the measurements do not go above PD parameters. If they do, you can still apply under full planning to get planning permission for extension work, or conservatory planning permission.

• For the build you will require to get site insurance, since you are changing the structure. That is not covered in home insurance. The site insurance with a good insurance company to cover not only the new extension but also the host property. If you plan to relocate during construction, you should organise unoccupied buildings insurance instead.  
• Plan internal access so you don’t lose too much space in the new layout. Your architectural designer can help you with this. Think through the construction cost vs the space you will add. Remember an estimate is not a quote. Remember to budget for VAT on labour and materials. Use a VAT registered builder if you plan to claim VAT relief.
• Avoid designs which make the extension look stuck on. Your designer should be able to create a fluid blend of contemporary with traditional, and to match the materials. Building Regs say conservatories should look separate via external type door accesses, but if you are changing to an extension, it is a good design challenge to marry the new with the host. Most designs open up the living space via the removal of walls, but be aware that heat loss will need to be addressed. For this reason, Building Control says that only 25% of the new floor area should take up corresponding glazing (such as roof lanterns in the conservatory roof replacement.) These must also be up to UK standards). Heat loss is addressed in conservatories via external style doors and conservatory insulation.
• Right to Light is understandably an emotive concern for neighbours, and actually carries more weight than your existing planning permissions or rights under Permitted Development. However it is less of an issue in areas that are less ‘built-up’, such as detached houses on larger plots.
• Know your extension or conservatory building regulations, as you will need approval from Building Control even if your extension is a Permitted Development. This is to protect you from a build which has unsound aspects. You can start to build 48 hrs after notification of your conservatory building regs. You will also need to contact them if you want to alter a load-bearing wall.
• Add a bathroom or (en-suite) to make the flow easier, especially near the bedrooms. Four to five bedrooms should have 2 bath or shower rooms, in order to protect the resale value. Downstairs loos are popular, (especially regarding the elderly) but may not add much to the value. Building Regulations stipulate that each new toilet room to have adequate ventilation and a wash basin, yet no longer require an anteroom as part of the approach. A shower room can go anywhere and must be at least 90cm x 180cm, or 90cm x 260cm for a shower with toilet & basin.
• Down under is a possible solution to maximize space, especially if there is an existing cavity as it won’t eat into your PD allowance until you deepen it. Basement windows and access are not contentious for planning, although you would need to send a Construction Method Statement with your application to the Planning Department. To ensure compliance, see this basement resource. Construction costs to make habitable vary from £1K-4K/m², depending on excavation (£1K being is where no deepening is required, and £4K being full excavation.)
• Trees can present a problem: they could affect your foundations but cannot be removed if they have Preservation Orders! An arboricultural consultant can advise you.
• Trees can be a nuisance: they might affect your foundations but cannot be removed if they have Preservation Orders! An arboricultural consultant can advise you.