A Garage conversion is usually on the whole a cost effective and viable alternative to building an extension, however, certain points must be taken into consideration before undertaking any work.


Is the existing garage of solid construction?

Most garage conversions are usually of the type that is already an addition to the main house, i.e. the garage is either built onto the side of the house or even part of it with living space over the top.

Should the garage be constructed of other material than bricks and mortar, different methods will need to be employed to bring the new space up to the required standard laid out by building regulations.

A cheap timber construction (basically a shed) may well need to undergo such radical alterations as to render the project financially unviable as it would be cheaper and easier to start again from scratch. Concrete sectional garages may also be deemed unsuitable due to the waterproofing needed, the need for a damp proof course, roofing regulations etc.

Buildings having corrugated tin roofs, again usually separate from the main building would need a complete new roof, this also brings with it cost implications.

If the walls are of brick/block/other masonry construction then adequate footings need to be in place as does the required specification of concrete floor slab i.e. hardcore/concrete. If not this will also need to be addressed.

Is the garage of sufficient size?

If the required floor area would need to be extended then planning permission must be sought prior to building commencing as extending any building increases its volume and so certain rules must be followed.

Should the existing ceiling height be under 2,4m from the existing floor consideration must be given to the fact that when insulating an existing concrete slab, the floor height will be raised by approximately 100mm or more and the ceiling may be lowered by 50mm depending on the type of insulation required. The walls may well need to be insulated on the inside by up to 100mm thickness so all these factors go together to determine the finished internal dimensions of the space.

What services will be required?

Electrical power is usually a must but if excessive power is needed e.g. sunbeds, showers, heating then consideration must be given to the amount of current the existing consumer unit for the main house has left to give. A domestic consumer unit is fitted with a 100 amp main fuse so may need an extra phase installing to power the garage requirements in extreme circumstances at considerable cost.

Heating of some description is usually a must also and if the intention is to tap off the existing central heating system then consideration must be given to the route the pipework has to take and whether any of it end up outside the building. Usually it is a simple enough job to ‘T’ off the existing through 1 wall and feed 1 or two radiators but in the case of microbore systems for example, each radiator must be taken from a manifold within the main building.

Should the space require bathroom/washing facilities then a domestic hot and cold water supply will be needed along with waste drainage and possibly soil drainage. Is there a suitable gulley available along the outside wall leading to a sewer? Rainwater gulleys leading to soakaways are not suitable. Where is the main soil drain? Does it even run underneath the garage? Are there existing services to be aware of? Sometimes the rising main water stopcock can be in the garage exactly where you propose to knock through into the main house. Moving it is possible but requires extra work. The main electrical supply may run underneath where you propose to dig the footing underneath the garage door as may the water and main sewer pipe. How far down are they? Will a change of direction be needed?

Is the proposed use for business purposes?

Should you be thinking of converting your garage into a shop or a hairdressing salon then planning permission for change of use will be required.

For more information please search the internet for approved documents relating to Garage conversion. Ultimate handyman no longer links to any Government website as they keep moving or deleting the pages which leaves us with hundreds of dead links on our site. We cannot put a copy of the approved documents on this server as the documents are regularly updated and so you could be viewing an out of date document.

Once you’ve thought through the project and are satisfied you have the required funds and permissions to carry out the work and obtain the required completion certificate from building control then its safe to crack on.