There are only two circumstances that could affect the viability of an attic conversion
The HEIGHT of the roof and the SHAPE of the roof.
1. YOUR ROOF IS NOT HIGH ENOUGH
Well, what do you intend to use it for?
The vast majority of roofs are not high enough to qualify as ‘habitable accommodation’, so forget about that aspect. The conversion will, in almost all cases, be regarded as a storage room.
If you’re going to use the new room as a home office then ask yourself how much height do you need sitting at a desk? Are you going to be striding up and down the floor negotiating great deals on the mobile? Probably not.
But, if it is to be used as a play area for the kids? Or, as a den for teenagers? Or, even a bedroom for teenagers, that’s a different story.
They will love the space, they couldn’t care less how high or low the ceiling is.
However, if you are going to use it as a bedroom for adults then the height is important.
So how much height do you need?
Bear in mind that when an attic is converted properly; in accordance with current building regulations, a loss of around 6 inches in height is inevitable.
‘Height’ is the measurement from the top of the wood you are standing on (joist)
to the bottom of the ridgeboard (in older houses) OR, the bottom of the metal plate (in modern houses), above your head.
So, a finished height of 6 feet might be acceptable for kids’ rooms or a home office, but certainly not for an adult’s bedroom.
In certain situations the roof can be raised by putting a large dormer on the back AND increasing the rows of slates on the front. A dormer on its own will not increase the height.
We did this recently on the Dublin road in Sutton where two adjoining semis did it together. You can also see examples in the row of cottages when you cross the Eastlink bridge going south. As for doing this in a modern estate I’m afraid you won’t get permission. But you might have some chance if it’s a detached house.
2. YOUR ROOF IS THE ‘WRONG’ SHAPE (hipped)
(a hipped roof is one which has a slope at the side)
Although it is usually possible to get a decent size room in these attics, the biggest problem with a hipped roof house is that the existing stairs is nearly always on the outside wall where there’s no height in the roof for the new attic stairs.
In rare instances the stairs is on the opposite wall (joining your neighbour) and this makes it far easier to install the new attic stairs.
Sometimes the pitch of the side slope is steeper than normal so that a stairs will fit above the existing stairs.
But, in most cases there is a serious problem with the new stairs.
You have three choices.
- You could use a ‘fold down’ wooden attic ladder. Ok if the room is to be used as an office.
- You can build a new wall & door in either of the main bedrooms to form a corridor in which to house the new stairs.
- You can change the roof profile with either a side dormer or a dutch hip. Either of these will give the necessary roof height to allow a new attic stairs to be positioned directly above the existing stairs.
A word of caution
Since the new Dublin Area Development Plan came into force the planners have begun enforcing new rules on side dormers. They are insisting that side dormers be lower than the main roof. If your roof is fairly low as it is, a side dormer will be useless to you. In this case you would be better off with a ‘dutch hip’ which keeps the new section at the same height as the main roof.