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Garage Conversions

Garage Conversions

One of the simplest ways to gain an extra room is by converting all, or part of, a garage. Most single garages these days are used for ancillary storage/utility purposes and have enough space to make, for example, a useful bedroom with en-suite facilities.

Where the garage is attached or integral, it already forms part of the dwelling and there is no element of change of use. This is not the case where the work is to a detached garage, in which case a larger part of the Regulations can be brought into play.

Where the garage is attached or integral there are relatively few requirements that need to be met. The principal areas where work will be required relate to thermal insulation, means of escape, structure and ventilation.

Dealing with these in the order they appear in in the Regulations, the main points to consider are as follows.

Part A (Structure)

Where the garage door is to be infilled, it is usual to use masonry, with a window inserted below the existing lintel. There may be no foundation across the original door opening, so a new foundation may be required, or suitable lintels inserted below ground level to support the masonry infill panel.

If a new partition is needed to subdivide the space created, it may be more appropriate to use a stud wall, in order that the existing floor does not need to support the extra load of a blockwork wall. This should likewise be considered if the existing external wall is of single skin construction, as the edge of the oversite is unlikely to be robust enough to support a masonry inner skin required to create a cavity wall. This may be more easily created with an insulated studwork lining.

Part B (Fire Safety)

If the room to be created is an inner room, then a means of escape will be needed from it. This may be in the form of an external door, or may be an escape window. This requirement will not apply if the room created is a kitchen, utility room or other non-habitable space.

Where part of the garage is being retained, the separation between that part & any room created should be half hour fire resistant. Any door leading to a garage from the dwelling should be a FD30s door.

Part C (Protection from Damp)

The existing garage floor is unlikely to have a damp proof membrane (dpm), and is usually at a lower level than the house floor level. As extra flooring is to be provided it is usual to incorporate a dpm as part of the construction. Any infilling to the garage door opening should be suitable weather resistant, and work undertaken to ensure that the existing walls are made weather resistant too.

Part F (Ventilation)

The room(s) created should have appropriate standards of ventilation by windows, background vents and extractors where necessary. A new en-suite bath or shower room, or new kitchen will need extract ventilation, as will a WC if it does not have an openable window. A utility room, used for laundry purposes, will also need extraction.

Part L (Conservation of Fuel & Power)

In order that the building is thermally efficient the new construction (garage door infill & new floor) should meet current standards of insulation. Elsewhere it may be necessary to upgrade existing construction to meet enhanced thermal standards, but these may be slightly lower than the standards required for new construction. If the existing construction already meets an adequate standard, referred to as a threshold standard, there may not need to be any upgrading. New windows should meet the current standard.

If the existing garage was attached, with its own roof, then insulation will be needed to the roof space. This can be problematical if the roof is flat, as it may not be easy to incorporate enough insulation & achieve cross ventilation of the void. Such problems may need to be resolved on site when the work starts.

Electrical work undertaken will be subject to Part P and should be carried out by (or tested by) an appropriately qualified electrician.

The work to convert a garage will require a fee to accompany the application. This will require an estimate of cost being submitted. This estimate will relate to what a builder would charge. The relevant fee can be calculated from Table 3 (Fees-Other) of the fee schedule.

Garage conversions can often be undertaken without Planning permission, but the Local Planning Authority, whether the New Forest District Council or the National Park Authority, should be consulted to ensure if this is the case.

Updated: 23 Oct 2014
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