2/17/2023

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Dormer's have been referred to in many different ways, Dormer windows, Dormer extensions, roof extensions, attic extensions.

A brief description of a Dormer would be an extension of an existing roof shape. Consider a most typical terraced property/town house where the roof would start at the gutters at the front of the house rising to the Apex, the ridge in the centre of the house, then falling again down to the gutters at the back of the house. This most typical roof shape does not usually produce a substantial habitable room, unless the house is unusually large. So with this type of roof structure, it would be advisable to extend the roof and create a Dormer (usually to the rear of the property.)

The size, shape and general design of this or any other Dormer can vary greatly. This type of conversion may also not require planning permission. Householders have what is known as a permitted development allowance. This permitted development allowance is usually measured in cubic metres. The amount allowed (cubic metres) varies from property to property. Generally, the allowance would be between 50 and 70 cubic metres or 20% of the overall volume of the property.

A Surveyor from AH Building Contractor can easily calculate the required volume for any dormer and whether or not this would fall within permitted development rights. Please note, there are further guidelines whilst trying to identify if your project would be allowed under permitted development rights.

These are:

  • No part of the new structure must rise any higher than the existing highest part of the roof at present (usually the ridge line.)
  • Looking down on a plan, no part of this new structure must exceed the current floor plan boundary.
  • The property must not be in a conservation area.

Again, as per roof line conversions, even if planning permission is not required, Architect's plans along with Structural Engineers calculations will be necessary to conform and to comply with the current building regulations.

If you are in any doubt whether your proposed project would require planning permission please do not hesitate to contact one of the Surveyor's at AH Building Contractors.

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It was really nice to receive such a friendly service. The workmen were great- very friendly and full of information and advice. The office staff were there for us every step of the way and we were made to feel special and valued. Our final result was the icing on the cake - it was great and my wife and I are thrilled.

Sam Livesey Stockport

One of our friend's had recently had an extension with AH Building Contractor and recommended them to us. It was the best recommendation we have ever had. AH Building Contractors built a two storey rear extension which was formed into a dining room and bedroom and the results were fantastic.

Mr Crowley Stockport

We called AH Building Contractor as we wanted to create extra living space, but we were unsure which way to proceed.  The advice and professional design options they gave us was unbelievable.  We would never have thought we could create so much space and blend it so well with the existing house.  We can't wait for the dinner guests to ask 'how did you do this'  'Did you use professional interior designers' - We certainly did they are AH Building Contractor of Manchester!

Mr & Mrs Holloway Manchester