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Two Storeys Extension - Limitations & Conditions

Updated: Sep 1, 2023

Two storeys extension - Limitations and Conditions
Renovations - Two storeys extension

Adding Two storeys to your house without Planning Permission? What are the Limitations and Conditions?

As per the New Permitted Development Rights and as of 1st of September of 2020, upward extensions are allowed on existing homes.

The new permitted development rights are established by The Town and Country Planning (General Permitted Development) (England) (Amendment) (No. 2) Order 2020. They allow:

For a detached house that is two or more storeys high, you can add two storeys.

For a semi-detached house, you can go 3.5 metres higher than the house with which you share a party wall

For a terraced house, you can only go 3.5 metres above the rest of the terrace.

For a bungalow, it can become a two-storey house, but not a three-storey building.

For all houses, the roof type must match what you have right now. This is important because it will stop you using a flat roof or mansard roof to get the maximum amount of room while staying under the height restrictions.

Are There any Other Specific Limitations and Conditions for Extending Upwards?

Each storey can either be a maximum of 3 metres high internally or the internal floor-to-ceiling height of the tallest existing storey, whichever is lower. You can add a maximum of 3.5m in total to a one storey house and 7m to one that is two or more storeys high.

The highest part of the roof cannot be taller than 18m.

The new storeys cannot extend past the front or side of the current building

If the existing house is two or more storeys high (not including basements or loft rooms), you can extend your house upwards and add two storeys under the new permitted development rights.

If the building is only a single storey currently, you can only add one more storey under the new permitted development rights. For example, a bungalow

The new floors have to be built on top of the main original footprint of the building. So, if you already have an extension you are not allowed to use the Permitted Development Rights to add extra floors above it.

You need to make sure you aren’t overlooking or having an impact on the privacy of neighbouring properties or causing loss of light by extending your house upwards.

The rules related to Materials in this Order are straightforward: you need to make the new floors and new roof look as much like what you have already.

Which are the No's that one should know?

MTM Vision LTD can guide you in getting this upward extension to your home without a planning permission BUT first we will go through a quick check on who can use the right and who cannot.

So the No’s that stand for all permitted development rights are still there as below:

Conservation Area, National Park, Listed Building, Area of Outstanding Natural Beauty, New Storeys added since it was built.

The additional No’s here are:

Houses built before 1 July 1948 or after 28 October 2018 (for extending homes) or 5 March 2018 (for adding new flats) cannot be extended upwards without planning permission.

We strongly advice against false declarations of when a house was built. Planners have that information, and you can be fined over these false declarations

The existing house has to currently be used as a single home – not flats or an HMO. And both the existing house and the new flats will then have to continue in use as “dwelling houses” – homes, not HMOs or any non-residential purpose.

IMPORTANT NOTE: you will need prior approval from your council to use any of the new permitted development rights including extension of houses upwards.

Why use MTM Vision for your new Upward Extension:

Permitted development projects are treated as minor stuff that can be handled by local builders and even expert DIYers. But if that was ever true, the expansion of permitted development rights means they now cover major construction work.

So you should consider hiring a fully qualified architect to guide you through the regulations and to make sure your new home or building with flats is safe as well as compliant with all the regulations.

Along with prior approval for your upwards extension, you will also need building regulations approval – and that will be much easier to achieve if your new storeys have been properly designed from scratch

MTM Vision LTD will offer you solutions in terms of room layout for your residential design so that you end up with a house that is not only bigger, but also more efficient. And if your building flats, we will come up with a design that will make your investment even more profitable.

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