Looking for extra space in your home but understandably reluctant to move because you love the area you’re in? It is at this point that many householders consider a loft conversion.
Certainly, if you are not using the loft for storage then that is a lot of potential home space going to waste. And, really, do you need half the stuff stored away in there anyway? Perhaps not when you consider it is possible to turn it all into a new room within the space of around 10 weeks!
Planning requirements for a loft conversion
Still, how can you tell if your loft is suitable to turn into an office, spare bedroom, teenager den etc? Well there are legal requirements.
The first is that there has to be a head clearance height of 2 metres. If your house was built in the 60s or later then you are in luck as most have this. If it was earlier than this then it is worth getting in a specialist to double check before you go start making any plans. It is possible to lower the ceiling of the rooms below, but this will, of course, add pretty substantially to the cost of your loft conversion in the capital.
Other obstacles that can get in the way of a good loft conversation include a chimney and even an old water tank. The pitch of the roof should not be too steep either (30 degrees or more is ideal).
If you live in a house which is listed or sits in a conservation area, then planning permission will certainly be necessary.
Permitted development rules
As a rule, you do not need planning permission from your local council for building a loft. That is because since 2011 this type of construction and property design work has come under the category of permitted development. If you live in a detached house though you will need a party wall agreement with the neighbours.
There are conditions however – and your designer will no doubt advise you on these. Basically, they refer to the width and height of your loft conversion ie it must not be larger than 40 cub metres (terraced house) and 50 cubic metres (detached and semi-detached homes). Nor must the loft extension be higher than the roof or overhang any walls.
In order to protect the privacy of neighbours any side windows must be obscure-glazed.
Different types of loft conversions
There are four main types of loft conversions around today. These are:
· Velux. This is basically a way of adding light via windows to a loft room (Velux being the name of the windows used). The windows take the form of skylights and the structure of the loft does not alter.
· Dormer. Great for bungalows, these add extra floor space, (usually at the front of the loft) and are shaped like a rectangular box. It is also possible to add on a side dormer so that the entire conversion is L-shaped.
· Mansard. The largest type of conversion, this includes adding on extra space to the roof horizontally and vertically. It can provide enough floor space for a couple of additional rooms, but it does require planning permission.
· Hip to Gable. This is when the sloping roof is replaced with a vertical wall (therefore extending the space at the side/s). Again, it requires planning permission.
Wish to build within your Permitted Development Rights?
Don`t exceed the highest part of the existing roof
Don`t extend beyond the plane of any existing roof slope which forms the principal elevation of the dwellinghouse and fronts a highway
Don`t exceed 40 cubic metres in the case of a terrace house, or 50 cubic metres in any other case
Don`t include verandah, balcony, raised platform, or the installation, alteration or replacement of a chimney, flue or soil and vent pipe
All materials used must be similar to materials already existing
Any upper-floor window located in a wall or roof slope forming a side elevation of the dwellinghouse must be obscure-glazed.
No part of the enlargement extends beyond the outside face of any external wall of the original dwellinghouse
How much does it cost to buidl a loft conversion?
What a difficult question!
In London the average for a loft conversion within PD it`s around £35K. But there are several factors that can change it.
- Existing roof: not all the roofs are suitable for conversion, the first thing to check is the internal height, this should be at least 2.2m because when you convert the roof you need to insulate it, so a build up of around 300mm will be added, and the remaining 1.9m is the minimum required headspace for the stair. If the loft it`s lower than 2.2m you might need to demolish the floor and move it down or, if you can, decide to make the roof higher.
-Windows: you can have velux windows as well as juliet balcony or those new systems that open up in a small terrace, and of course the prices are quite different.
-Use: if your conversion includes a bathroom the cost would be higher than a bedroom alone.
The only way to know the exact quote for your project is to provide Technical and Structural Drawings to your contractor. you can get an idea with Planning drawings but this will not be your final figure!
For a first approach you can budget in this way:
15% Substructure and Structure
15% Floor and Walls
9% window and doors
9% Mechanical and electrical
9% Kitchen and Applicances
An important point that we like to highlight is that if you would like to build your extension using sustainable construction methods instead of traditional, your costs will not increase as you might think!