Wish to build within your Permitted Development Rights?
Don`t build on land forward of a wall forming the principal elevation.
Have to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.
Maximum height of 2.5 metres if within two metres of the boundary.
Don`t build verandas, balconies or raised platforms.
Don`t build more than half the area of land around the "original house"
If it is more than 30sqm or it have drainages then Building Control Notice is required.
If it is within 2m of the boundary should be build mostly with non-combustible materials.
How much does it cost to build an outbuilding?
In London the average it`s about £35K for a garden office. There are few points to consider that can change this number:
- Foundations: concrete or timber frame? Matter of durability
-Windows: the difference in cost between a uPVC single pane window and a 6 panes bifold aluminium door it`s massive! Same for skilights, those can be fixed or openable and have special glass to protect you in sunny days.
-Use: residential use instead of office or gym can increase the price.
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!
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!