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PLANNING
Do you need planning permission to turn your front garden into a driveway?
You can replace or install a new hard surface in front of an existing house without planning permission if the area is less than five square metres. For some small front gardens, that will be enough for a ‘wheel tracks driveway’ — i.e. one that has just two paved tracks for the wheels of your vehicle.
If you require a driveway larger than that, you can still avoid the need for planning permission by laying a permeable (or porous) surface, such as gravel, permeable concrete block paving, or porous asphalt — as long as the rainwater is directed to a nearby lawn or flower border to drain naturally.
If you are converting some or all of a front garden into a driveway, then you will probably need to drive over a pavement to get to it from the road. In this case you will almost certainly require a licence and/or planning permission for dropped kerbs from your local authority.
AIRTIGHTNESS
A blower door test is a way of measuring how airtight you have managed to make your newly built home. Airtightness is typically measured as air leakage — an uncontrolled movement of air into and out of a building — expressed as X m3/hr/m2@50Pa, or as the air change rate, expressed as X ach/ hr@50Pa. A higher amount of air leakage indicates poor airtightness, while a lower rate will prove your home is relatively airtight.
Measuring airtightness is an important part of a fabric-first approach to building. Fabric-first is all about building a house that has a decent enough level of airtightness so that space heating can be significantly reduced to little or, sometimes, none at all. Achieving this makes the finished home not only more carbon friendly due to less reliance on fossil fuels, but also cheaper to run.
The blower door test is all about measuring this to assess whether you have achieved a good level of airtightness, and if you haven’t, looking at where improvements can be made. Airtightness checks are also needed on new-build homes to be able to complete your ‘as-built’ Standard Assessment Procedure (SAP) for building regulations. You need to confirm that you’ve achieved the airtightness performance as set out in your design SAP.
What is a blower door test and does my self-build need one?
There are plenty of blower door test providers; some are solely air and ventilation testing firms; ot
