Adding a New Storey as Permitted Development

Can I Add a New Storey to my House?

Since August 2020 the UK Government permitted homeowners in England to add a completely new floor, and in some cases 2 floors! We have sifted through the new regulations to explain these new allowances in summary form, as follows.

Adding a storey as Permitted Development is only permissible for properties built between 1948-2018 AND if the property:

  • Is NOT listed;
  • Is NOT in a Conservation Area;
  • Is NOT in a National Park;
  • Is NOT in an Area of Outstanding Natural Beauty;
  • Is NOT in the Broads;
  • Is NOT in a World Heritage Site; and
  • Has NOT had any new storeys added since it was built.

So, the above criteria counts in about 62% of residential properties but if you are in the 32% of properties that don’t qualify, it doesn’t mean you can’t extend upwards it just means you will have to apply for Planning Permission to add a new storey. If however you are eligible, you can add up to 2 storeys, but only above the original footprint of the house, and you can even convert the additional storeys into separate flats to boost the value of your property, all without the hassle of making a planning application.

Detached Houses

If you own a detached house with 2 or more storeys (not including basements or loft conversions) you can add up to 2 further storeys. If the property is a bungalow you can add one more storey. You can also add flats within the extra floor if you wish. The new roof must resemble the previous roof and the pitch angle must be kept the same. You can’t extend upwards of more than 7m and the total height of the house must not be more than 18m.

Terraced And Semi-Detached Houses

If you own a semi-detached or terraced house, you can add a floor using Permitted Development up to 3.5m above a neighbour’s roof which is attached to yours. You can also add flats within the extra floor if you wish. The new roof must resemble the previous roof and the pitch angle must be kept the same.

Conversion Into Flats

The new Permitted Development regulations also allow property owners to convert the new floors into separate flats without planning permission. This can offer an easy way to increase the value of your house as previously splitting up a property like this was a difficult process via planning. As well as the standard considerations when adding a floor, like neighbours’ right to light and privacy, you also need to consider the effect on access (vehicular), transport links and local amenities by increasing the headcount through the additional flats.

What Can’t I do if I Add a Floor to my House as Permitted Development?

  • You can’t extend upwards beyond the original footprint of the property e.g. you cannot extend over an existing extension or on top of an existing loft conversion;
  • You cannot count a below ground floor or loft conversion as an original floor of the building, only ground floors and original first floors;
  • You can’t change the roof pitch or style e.g. a terraced house is allowed to go up 3.5m but you cant change a pitched roof to a flat one to squeeze 2 storeys in;
  • You can’t use materials that are different in appearance to those used on the current exterior of the property ;
  • You can’t overlook your neighbours which means no side windows;
  • You can’t cause loss of light to your neighbours – specialist light surveys maybe required, particularly in urban built up areas; and
  • You can’t use your Permitted Development Rights to extend upwards and then at a later date convert the new loft to living space – you will need to apply for Planning Permission to do that.