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Extending your home - what to consider

Extending your home can be a huge time and cost outlay so you should make sure you fully understand the legal, planning and build issues you might come across on the way. Planning the way your new home will look is the easy part, but the more complicated areas are often left to the builder.

To help you feel more confident about the process we have put together a top 5 list of things you should be aware of before you start your project.

Building regulations – you’ll need them

Image of steel beam being inserted into new masonry wall

You might not need planning permission for your project (visit the interactive house on the planning portal or contact your local planning department to check) but whatever size of extension you are planning you’ll need to make a building regulations application to building control before you start work.  Building regulations cover the structure, energy efficiency, safety, insulation, ventilation and materials. You can find out more about how to apply and the process here.

Sewers can really affect your plans

If your extension is going to be built over or within 3m of a shared sewer you will need to contact your water authority before you start to apply for a ‘Build Over’ agreement. This can be costly and sometimes time consuming, especially if the sewer has to be moved or a manhole is needed.

Are you in a conservation area?

Each council has its own policy on conservation and even if your extension doesn’t need planning permission if you live in a conservation area you will need to contact the local conservation officer as one of your first steps in the process. (This applies even for minor works such as replacing windows.)

Are your foundations good enough?

When your home was built, the foundations would have been dug to take the load as it was originally designed.  In the last 25 years building regulations have stated that foundations for an extension should be deep enough to allow an extra storey to be built later. However, this rule doesn’t apply to garages so if you are thinking of building over your garage you may need to carry out extra foundation work.  Basically, you need to work out if your foundations meet the regulations and whether the cost and disruption may be cost prohibitive and extending your property elsewhere may be a better option.

The impact of energy efficiency

Image of section through upvc window frame next to energy ratings chart A-G

Only in recent years has energy efficiency become such a huge consideration.  You’ll need to ensure you extension meets building regulations rules for thermal efficiency.   This affects your choice of windows, wall construction, insulation and ventilation and could have an impact on the whole design. If for example you are thinking of an extension with large expanses of glazing to make the most of the views you may need to include expensive double or triple glazing to meet the requirements.

If you’re thinking about extending your home take a look at our Guide to Extending your Home or contact our building control team who will be happy to discuss your project with you.