10 things you need to consider before starting an extension

Extending offers great potential for transforming your home, adding value and much-needed room for growing families, but there's a number of - important - things you'll need to think about beforehand.

If you're dreaming of an extension, here are 10 things you should consider before getting started...

1. Do you need planning permission?

Before you think seriously about starting your extension, it's vital to make sure you have the correct planning permission. Although the majority of extensions can go ahead without seeking permission, in some cases (such as listed buildings or height restrictions), future plans can become halted.

Referring to your local council's website or to the 'permitted development rights' system is a helpful way to find out whether there are any restrictions in place that could hamper your plans before they've even begun.

2. Is there adequate access to your house?

It seems obvious, but it's easy to forget how important it is to make sure you and the builders will be able to gain access to the property. Maybe you have a terrace house, maybe you don't have a driveway, maybe you've got low beams on your ceilings. From guttering to gateways, make sure you have all of the practicalities covered so that the work can feasibly go ahead.

So, if you do have a terrace property, meaning all the building materials will have to be carried through the front door and house to wherever they're needed, consider whether this is actually going to be possible. If you don't have a driveway, consider whether there is enough parking for yourself and potential builders. If you have low or beamed ceilings, consider if there is an alternative route for building materials to pass through.

• SPACE: An extension by Simply Extend. Picture: Simply Extend/PA

3. The conditions of your home's surroundings

You're getting to the point of drawing up plans, but are you sure you've scrutinised everything about your home and it's environment?

Issues such as soil conditions, surrounding trees, and any history of flooding could cause problems with an extension, so you should make sure you've checked them out before you go ahead.

4. Avoiding cowboy builders

We've all heard the horror stories about people paying thousands of pounds for building work that never got done. Don't worry though, there are trustworthy builders out there - you just have to do your research.

Has one of your friends done a similar project? Ask them for a recommendation. Speak to people locally who might know a good, reliable builder. And don't be afraid to call it quits if you're having doubts.

5. Does the design suit your existing home?

According to renovation expert Michael Holmes, extensions should seamlessly merge into the original part of the house. However, that doesn't have to mean matching materials exactly. "Choosing a different period style can work very well, designed as if the house has evolved over time," suggests Holmes.

• STYLISH: An extension by Simply Extend. Picture: Simply Extend/PA

6. Have you chosen the best bit to extend?

You might already have somewhere in mind, but is this definitely the best place for the extension? It might make sense to demolish a garage or shed to make room for the extension, or perhaps build on top? "It's usually more cost-effective to build over two storeys than one, because it spreads the cost of expensive elements, such as foundations and a roof, and sacrifices less garden space than a larger single storey," says Holmes.

7. Keeping the neighbours happy

Of course, you're free to build your own extension in whatever way you like (providing, as mentioned, you have the appropriate permission!), but do bear a thought for your neighbours. Even if planning permission is granted, it's courteous to at least inform your neighbours about your building plans. You'd be surprised about the number of neighbours who fall out over extensions, so be considerate and have a quick chat with them before work gets underway.

8. What it's all going to cost

Obviously, your location, the size of the extension and even things like soil conditions will all affect the overall cost of the work, but there are average figures which you can keep in mind.

According to homebuilding.co.uk, you should allow around £1,000-2,000 per square metre. Depending on the number of storeys, the cost of an extension can range between £10,000-£50,000, says Jill McLintock, product manager at everest.co.uk

9. How you'll cope when the building work takes place

The end product will look great - but the day-to-day logistics in the meantime can be tricky. "For a dust-free life, moving out and finding temporary accommodation can be one of the most hassle-free options, but that's not always possible," says Robert Wood, founder of SimplyExtend.co.uk. "If you do decide to stay in the property, it is likely you will have to navigate life - for a short period of time - with dust, no kitchen, and occasional breaks to the power and water."

At least take all the steps you can to make managing the upheaval easier: Invest in dust sheets, move other belongings to storage, and even take the family out for dinner more often so you can escape the mess.

• AT HOME: A couple in their newly extended kitchen. Picture: Thinkstock/PA

10. Don't forget the building certificates

Once the building work is complete and the extension of your dreams has become a reality, make sure you ask your builder or contractor for all the necessary certification, including building control certificates, electrical and gas safe certification. "Without these, it will be harder to sell your property later should you wish to," says Wood.