To qualify as permitted development some household building work projects – notably extending a house – must not exceed limits to the volume being added.  

In England, the volume allowance mostly applies to loft conversions. You can read more on the Planning Portal. 

Use the volume calculator to find out the volume of several loft conversion and extension types.

Building above an attached garage is treated the same as adding a storey to the rest of your home. This is considered to be permitted development, not requiring an application for planning permission provided you meet the set rules and requirements.

You will still need to submit an application for prior approval to your local planning authority.

Read the list of rules and requirements for extending upwards.

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Many homeowners choose to replace their traditional polycarbonate conservatory roof with a solid tiled roof for better thermal efficiency.

If the change significantly alters the structure or appearance of the roof, then planning permission may be required. Most alterations to roofs are considered permitted development, providing they meet the limits set out in legislation.

A new roof must comply with building regulations to ensure it is structurally safe, energy efficient and properly ventilated.

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Deconversion is the process of restoring a previously subdivided house back to its original state as a single property. Merging flats to create a single house may require planning permission, so you should discuss proposals with your local planning authority before starting work.

Read more about converting flats back to a house.

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By law, any planning permission granted expires after a certain period. Generally, unless your permission says otherwise, you have three years from the date it's granted to begin the development. If you haven't started work by then, you will probably need to reapply.