Loft conversions are a great way to get that extra space you need without the expense and difficulties that come with building an extension. Unfortunately they are not for every house though - when I moved to Maidenhead it became clear pretty quickly that we might need extra space, but a loft conversion was out of the question for several reasons. Here are some of the things to consider.
How much space is there?
This is an obvious one really but there are several factors to think about. Firstly in terms of floor area you will need to deduct an amount for the new stairs and landing, as well as the walls required to make a new lobby.
Then the really important space issue is head height. Most joists in lofts are not designed to take the load of a fully functioning floor of a house, and need to be enhanced. There are several ways of doing this, but all are likely to raise the floor level. Couple this with the fact that your roof will need to be properly insulated, and you will begin to see how large the finished room might be. Keep in mind that a usual ceiling height is no lower than 2.3m.
Can it be accessed?
This is one of the biggest problems in my house - there is nowhere to put the stairs without compromising a room! Generally the most efficient place for new stairs to go is above existing ones.
For two storey house projects, a loft conversion will technically increase the house to three storeys which has building regulations ramifications. This is all to do with escape in the event of a fire, and the most common solution is to ensure the stair from top to bottom is separated from other rooms in the house by fire doors. More information can be found in Part B of the Building Regulations, page 21. Something to be aware of, especially if your stairs land in an open plan living room.
What is the roof construction?
Have a look at these roof sections and see if you can match them up to your own:
Generally speaking, if yours looks like the one on the left the works involved will be easier than the one on the right. Houses built since 1965 are more likely to have a roof construction like the one to the right, with the trusses designed to work together to carry the roof load to the external walls. You take these away, and you are likely to need something more robust to support the roof - in either case make sure you get specialist advice before taking on any work.
Will it require planning?
This all depends on how ambitious your project is. Many loft conversions fall under permitted development (check out my post on permitted development here), but be aware if you want to increase the overall roof height or add dormer windows to the front elevation then it will probably require planning permission. Again, it's best to check with a professional or your local council first.
Use this as a checklist to see how achievable your loft conversion is, and if it still looks appealing then why not get a professional involved for some advice - here's one for starters!