Self-Contained Accommodation in Outbuildings

If space is tight in your property and the current economic situation makes a move inadvisable, then converting an existing outbuilding into self-contained accommodation can be a good way to get the extra space you need.

It can be used as an annexe for an elderly relative, a teenage bolt-hole, guest accommodation or even rented out to provide supplementary income. You can build something in the garden if you don’t have any existing outbuildings.

Planning Issues

Planning permission will almost certainly be required when extending your accommodation in this way as well as building regulatory approval. In England and Wales new rules were introduced in October 2008 to relax planning laws and structures built in the garden are now considered 'permitted development' and therefore do not need planning permission.

However, accommodation is expressly excluded from this rule. So rather than looking for ways to get around this it's easier to bite the bullet and start by discussing your plans with the local planning office.

Serious Plumbing For Accommodation In Outbuildings

The major functional difference between self contained accommodation and something like a home office or studio is that you will need to put a proper bathroom or shower room in with a toilet. This means connecting to a water supply, having a way of heating water, and connecting to the sewer system. It makes the job more complex as you would be unlikely to put all that into a separate extension that would only be used occasionally.

Unless you have done a lot of other plumbing jobs this is best left to an expert. Connecting to a sewage system is not something that you want to have problems with. Nor do you want anything to go wrong with the water supply to your main property if you get that connection wrong too.

As far as hot water goes you could install a gas fired instant boiler if the gas main is near enough to the property, otherwise the cheapest to install would be a hot water cylinder and an electric heating element. It might not be the cheapest to run though.

Insulating And Damp-Proofing A Separate Building

Other areas that might differ with accommodation rather than extending for occasional use are the insulation, damp-proofing and heating. The more you insulate an outbuilding the easier and cheaper it will be to heat, so if it is a single skinned building it would be wise to add a layer of internal insulation then plasterboard cladding.

A damp proof course is advisable although how much and how it is installed depends on the construction of the building. If you are extending by building a standalone timber building then a concrete base with a damp proof membrane incorporated into it is probably the easiest option. Wooden buildings can also be made reasonably damp proof by raising them off the ground slightly on blocks, perhaps with a slate in-between as well.

Heating For Self-Contained Accommodation

As far as heating goes, the better the insulation the less it will have to be heated. With a single room extension such as a home office or studio you can probably get away with a single electric radiator or portable propane gas heater, but self contained accommodation is likely to have more than one room and as such will probably need a network of radiators.

These could be electric but they do tend to be more expensive to run than a gas central hearting system. If gas is available and you're putting a boiler in for hot water anyway then it makes sense to extend the system to cover a few radiators. To be honest it depends how much you want to spend and how warm you need the place to be.