Planning Permission and Glazing
Do your new windows need planning permission?


By Slimline on 29 September 2017
Posted in Property

So, you’re thinking of putting bigger windows in, or maybe a porch or conservatory, or possibly a glass box extension. It’s time to call in the glaziers and get the job done.

...Or is it?

Before you start making any changes to your home, you need to check that you comply with any local planning laws – and that includes glazing. And just to make things a little more complicated, the rules can differ from council to council. What is permissible in one area may not be ok in an area of historical interest, for example.

To help you get to grips with the laws, let’s take a look at some basic general rules...

Is Planning Permission Needed When Replacing or Adding New Windows?

Putting new windows in does not require planning permission, and it’s also ok to install double glazing. However, there are a couple of provisos to be aware of; if conditions were placed on your property during the original planning permission, check that there is nothing that stops you replacing your windows. If your house is listed, there may also be conditions you need to be aware of.

If you are installing a new window (where there was not a window before), or replacing an old window with a larger one, you need to make sure the structural aspect comply with building regulations. This basically ensures the house remains safe and secure from risks such as fire or subsidence etc.

Planning Permission For Upper Floor Windows

If you’re thinking of putting a new window in upstairs, you won’t need planning permission, as long as any new windows on the side elevation use obscured glass and don’t open. The exception to this is if the window at a height of 1.7m or more above the floor. This is to maintain privacy for you and your neighbours.

Is Planning Permission Needed For a Single Story Extension?

Anything that sticks out form the original footprint is classed as an extension, including bay windows, porches, conservatories and glazed extensions. However, the good news is – if you follow these rules you won’t need planning permission:

  • The materials of the extension must match that of the original building
  • The extension is not in the front of the property
  • If it is within 2m of the property’s boundary, the height to the eaves must be no more than 3m and 4m height in total
  • An extension out the back can’t be more than 4m in depth on a detached house, or 3m on a terrace or semi-detached property
  • The width of a side extensions should be no more than half of the original building. In certain areas, side extensions are not allowed. Examples include AONB or Conservation areas.

Check out for a more detailed description.

Is Planning Permission Needed For a Rooflight or Skylight?

Installing a rooflight doesn’t require planning permission, unless they extend out from the front of the roof on the side that faces the road. But if they less than 15cm from the slope, this is permitted. If you live in an AONB or Conservation Area or similar, rooflights aren’t permitted.

Is Planning Permission Needed For a Porch?

Porches are the exception to the rule that says no forward-facing extensions are allowed without planning, as long as its lower than 3m, it’s not within 2m of the road boundary, and the ground area is less than 3m².

Of course, when it comes to any modifications to your property, there are always exceptions, and every council has slightly different variations. So, if in doubt, check it out!


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