House Extensions
Extensions are more about creating space than adding value to your property, although it is of course an important consideration. It is often more affordable to extend your home than to move into a bigger one, especially if the difference in house price to the next size up is considerable.
Whether a house extension is possible is depends on your ownership of the land on which you wish to build, and on having your plans passed by Planning Permission and Building Regulations.
Extending your home can be quite stressful; rendering some areas of the property ‘no go’ and creating an unavoidable mess for a time. That said, it is often less hassle than moving house.
Costs:
Prior to starting work on your proposed extension there are costs to be considered. You will need an architect to draw up the plans, and fees will be payable to both your council for Planning Permission and Building Regulations approval. Costs in the design will naturally vary dependant on the size and type of your extension.
If your plans involve the need to knock down an exterior wall to extend the property you will require a structural engineer to calculate the size of RSJ – this is the beam that will support the wall across the newly created gap. A quantity surveyor is needed to work out the cost of the beam itself. Always remember that plans may be forced to change when things occur or are discovered after the work has commenced. It is advisable to set aside a level of contingency funds in case extra costs emerge.
Planning:
To gain Planning Permission and Building Regulations approval, your extension should blend with the existing property and the surrounding area. Material should be kept similar to the original building where possible, and the design should reflect both the existing scale and character. This continuation of the original building should be carried through to decorative effects and windows. Care should be taken that the extension does not overtake the property and dominate its appearance.
The proposed extension should not affect any neighbouring properties. It should not reduce your neighbour’s privacy or daylight, and should not negatively impact on their view. If it is inevitable that your extension will overlook your neighbours, for example with terrace houses, the windows should be at least 22 metres apart and use frosted glass to prevent loss of privacy. A wall or fence to obstruct the view can also be erected, or you can install high windows or roof lights. If the extension is at the rear of the property, it should not interfere with neighbouring properties whether by blocking light or view, evading their privacy or even by physically altering their property. This also applies to conservatories. Extensions at the front of the property are rarely allowed as they will inevitably affect the overall appearance of the street or neighbourhood. If a front extension is to meet approval, it must stringently adhere to the original design and form of the property and neighbourhood dwellings.
Considering the exterior of the property; an extension should not be created if it will reduce the number of parking spaces and thus cause problems with road traffic or safety. Any trees around the property should be left alone and remain unaffected by your development plans where possible.
The 45º Test:
According to the Building Research Establishment guidance which is endorsed by Councils, site design for a house extension should pass the 45º test when considering daylight access for neighbouring properties. Taking your house plans, draw a diagonal line at 45º from the highest corner point of the wall where your neighbour’s window is located. Then draw another line at 45º from this plan toward the window wall at the end of the extension. If the middle of this main window on the neighbour’s house lies on the extension side of both these 45º lines, the extension may obstruct light into the window. The test however, is just a measure of guidance and does not result on definite approval or denial.
