Your best bet is to choose between something that joins seamlessly with the style of the rest of your house, or something focal and fabulous. Glass extensions are all the rage and can look fantastic, even on period homes, but don't choose something that will jar and put off future buyers. Brick also gives the option of going for a two-storey structure.
This modern extension has been cleverly melded with the Victorian house it's attached to by extending the wood panelling used as exterior cladding to the upper floors, and by blending the colour of the original window frames with that of the new ones on both levels.
An extension means a smaller garden, so weigh this against the benefits of extra space - your house may be harder to sell if the inside space is out of proportion to that outdoors. But, most likely, an extension will make your life better and attract future buyers. Try to squeeze in desirable lifestyle extras, such as a utility room or a downstairs cloakroom, to maximise buyer appeal.
When adding extra space, look at your house as a whole and decide what you need in order to maintain a balance. In other words, don't add extra bedrooms if the living room is tiny. Extensions, by virtue of being on the ground floor, lend themselves to family-friendly kitchens and dining rooms. The key thing is to have a workable plan in place before you start.
Prices vary depending on what you do, but at its simplest, an extension could come in at about the same cost as moving to a bigger house. Assuming you'll get your money back is a mistake, as so much depends on the market value of your home.
'You must remember that the average price of properties in the area will dictate the maximum price your property can achieve,' says Peter Bolton King, chief executive of the National Association of Estate Agents (NAEA). 'If average prices for similar properties are £300,000, for example, it's unlikely that adding an extension will increase the value of your home much above this threshold. Adding an extension should be a lifestyle choice, as it's possible it will cost the same amount to build as the value it adds to your property.'
You can create extra bedrooms, bathrooms and more living space by converting loft space. With starting prices at around £8,000 to £15,000, it's cheaper than an extension, and most lofts are suitable for conversion provided they have a minimum roof height of 2.4 metres. Disruption is minimal, especially in the early stages, as access is usually gained via scaffolding from the roof, and the work should be completed within a month or so.
You'll have to get a fixed stairway installed, so in addition to the new rooms you'll need to allow for the cost of redecorating the hall. Whether a loft conversion adds value to your house again depends on the local market. It is vital, in any case, that the finished structure looks integral to the whole house and not just a badly bolted-on afterthought. An extra bathroom is especially desirable, and you may have room for a bedroom with an en suite.
Basement conversions can be a great solution in certain circumstances. It's far easier to convert an existing cellar than dig out beneath the house. If you have to dig, you'll probably have to move out during the work and there are structural issues, such as underpinning and party wall agreements, to address.
It will need waterproofing, plus heating and ventilation systems. As soundproofing will be good, the space would be ideal for a den or home studio. It will take at least 12 weeks to complete.
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