You can extend your roof space by up to 50m3 (or 40 m3 for terraced housing) under Permitted Development Rights. This is providing the allowance hasn’t previously been removed or used up. This can save you the hassle of gaining planning permission, but there are strict limits to follow.
For example, no additions are allowed at the main elevation beyond the plane of the existing roof slope. Also, you can only use materials similar in appearance to the existing house.
Permitted Development Rights are removed for loft conversions exceeding the 40 m3 to 50 m3 space allowance, in conservation areas and in other designated zones, so you’ll always need full planning consent in here.
Building Regulations, party walls and safety
Loft conversions always need approval under Building Regulations (irrespective of whether they need planning permission). It pays to adopt the full plans application approach and have a detailed scheme approved before you find a builder. Having an approved design will take much of the risk out of the work and also mean the builder has a chance to give you a fixed quotation, rather than a vague estimate.
Your Building Control officer will inspect the work at various stages. On the final inspection they should issue you with a completion certificate — don’t settle any final accounts until you’ve received the certificate.
If your house is semi-detached or terraced don’t forget to notify your neighbour(s) of your proposals. This requirement usually falls under the Party Wall Act 1996.
From April 2015 homeowners are now responsible for safety on their building projects – big or small. All projects will require a health and safety plan and you will be required to manage that plan.