Unless your home is relatively new, or subject to other restrictions you can in all probability carry out your loft conversion or dormer loft conversion without needing planning consent as long as the following is true:
1) Your home is a single dwelling and NOT a flat or maisonette
2) You are only looking to add a dormer to the rear of the property (skylights are allowed, as are hip to gable conversions or side dormers).
3) The total volume increase does not exceed 50m3 for semi detached houses or 40m3 for terraced houses. It should be noted that if you are end of terrace and there are more than 2 houses in the row, your property will be classified as Terraced and NOT Semi detached therefore your maximum roof volume increase will be 40m3 and nit 50m3.
This is due to the permitted development order which allows homeowners to carry out home improvements such as loft conversions or house extensions without needed full planning consent.
Even if you do not require a full planning application, you can apply for an optional lawful development certificate from your local authority. This is a legal document that states that planning permission was not required for your loft and is worth its weight in gold if/when you ever decide to sell your home.
There are other stipulations to the design in order to comply however we wont go into all of these here – if you are generally interested then a quick look on the governments planning portal will quench your thirst for knowledge.
So I don’t need planning? Can I just call a builder and go full steam ahead with my loft conversion?
We’re afraid to say the answer to that question is a resounding NO
You will still required Building Control approval for your loft conversion – this is applicable in Every Case and if your contractor or anyone else tries to tell you otherwise then say your goodbyes to them and run for the hills!
Building control or building regulations approval is obtained through two stages. The first of these stages is at the Application and Plans Check stage. Once your plans have been approved, the second stage of checks will run alongside the building works and assuming the Building Control Officer is happy with everything carried out on site your loft conversion will be approved and a completion certificate provided.