The Design Process

Initial Design Considerations

The process of designing your garage conversion is generally straightforward as the size is dictated by the existing structure.

However, we have included below a summary of areas that you will need to think about and decide on before you progress to the building stage.

It is important to be sure that you have looked at the options open to you and gathered as much information as possible before you proceed with a specific design. It will cost time and money to change your mind later on and, when all the work is completed, you should be satisfied that you have the best solution for your needs.

We would strongly recommend that you use an experienced architectural designer to carry out your initial scheme design as they will be familiar with the limitations that are imposed by building regulations and they will know how to make the most of the space available.

myhome mygarden can provide you with a comprehensive Feasibility Study for any garage conversion proposal that you are considering which is an excellent way of finding out what the possibilities are at your own home.

The main considerations you will need to think about at this stage are listed below.

A. Your Requirements

Often know as the 'Client Brief', your first task is to define what you actually require from the conversions.

These rooms are often multifunctional rooms and can be used as a place to relax and watch TV as well as a guest bedroom, perhaps using a sofa bed. Garage conversions are versatile and are also commonly used for gyms, home offices, kitchens and granny annexes (often by converting double garages).

If you have a double garage, you may consider a partial conversion, leaving one half still usable as a garage.

Most designers like to have a clear Client Brief from you so that they can help you to create the space you need and give you an idea of furniture layouts. If necessary, create a list of priorities, dividing it into essential works and desired, but not essential works.

 

B. Glazing

One of the main design decisions with garage conversions is how to deal with the existing large door opening(s).

Most projects involve partially bricking up the opening and installing a window that matches the rest of the property as shown in examples 1 and 2 below. It is easier to make the window he same width as the existing door opening but this may appear too large so it may look better to reduce the width of the opening.

You may wish to make more of a feature by including a bay or a bow window as shown in example 3.

You should also consider including a new window or door to the existing walls (to the side or rear) to improve light or access but make sure you have thought about furniture arrangements before you decide on this.

C. Access and Levels

You will need to decide on the access to the new room if you do not already have an internal door. If you do, it is likely to be a fire door with an external quality frame and you should consider changing this to a standard internal door and door lining.

The new room should be accessed off the main hallway if possible and we would recommend raising the floor level to match the house (garage floors are usually lower).

You may need to add or replace the ceiling and provide insulation if it is an external building. Try and make the new ceiling at the same level as the house if possible.

D. Meters and Services

Ideally you should consider moving the gas and electricity meters externally to new boxes as this will ‘declutter’ the new space. However, if budgets do not permit this, then they can be boxed into a cupboard.

There are often a number of service pipes and often the consumer unit (fuse box) in the garage so ensure that you know how your builder intends dealing with these and be specific about what is included in his quotation.  

E. Budget/Value Considerations

There is sometimes a reluctance to talk about budgets at an early stage, but this can often be the single most important factor that determines your final design.

Whilst you will be building the space for yourselves, we would always recommend that you consider the resale value that your conversion will add. It will need to blend in well with the existing and it may be worth asking a local estate agent about the potential increase in resale value.

You may wish to consider designing the room in a flexible way so that it could easily be converted back to a garage by a future purchaser.

Our section on Garage Conversion Costs provides lots of information on cost influences that you will need to consider.

We would always recommend that you allow a contingency (we would suggest 10-20%) for the unknown when working out your costs at the feasibility stage

F. Planning and Building Regulations

Once you have decided to proceed with the design of a project, you will need to finalise the design details and to obtain any formal approvals required.

Your designer should be able to advise you on this matter and, if planning permission is required, make sure you are aware of any local planning policies that may restrict what you can build.

Planning Permission

Under planning laws, most properties have Permitted Development rights which allows a certain amount of development work to be carried out without the need for planning permission. Further information on this subject is available in our factsheet on Permitted Development

In most cases, planning permission is not required to convert your garage providing that you are not extending the garage where it will be treated as an extension or your Permitted Development rights have been withdrawn. You may need planning permission if you are adding a bay window as this increases the floor area of the building.

We would always recommend that you or your designer checks with your local planning authority if planning is required. For added peace of mind, you could obtain a Certificate of Lawfulness which is a formal confirmation from the planners that you do not need planning permission.

If planning permission is required, it is a good idea to have an informal discussion with your local planning office prior to making any submission as they will normally be pleased to give you guidance that could save you time and hassle in the long run.

Your designer will usually deal with the application for you, acting as your agent and will ensure that the plans are to the correct scale and include additional information required for the planning submission such as a location plan, block plan and a design or access statement.

For  more information on this subject, please refer to our factsheet on Making a Planning Application

Building Regulations and Working Drawings

Garage conversions will normally require building regulations approval as the work is likely to involve forming a new foundation and external wall, upgrading the floor to ensure it is damp proof and insulated and making sure there is adequate ventilation to the new space.

The existing garage may have single leaf masonry walls with piers which will involve additional work to try to improve both thermal insulation and weather resistance.

If you are providing a new bathroom, you may need to include new drainage which will also need to be approved by the building inspector.

Your designer will normally prepare building regulation drawings and submit these for approval to the council or to an approved inspector.

The drawings that are completed for building regulations approval are commonly known as the working drawings and these will contain all the information needed to ensure your proposal meets with the current regulations. They also need to be clear and have sufficient detail for your builder to be able to use to accurately to carry out the building work.

Other Approvals

You may need to obtain other approvals for your proposal and your designer will usually help you deal with these. You may need to involve your solicitor to check if there are any restrictive covenants and a party wall surveyor if your proposal is close to another property. We have provided factsheets on these issues below.
The Party Wall Act
Restrictive Covenants

Specification for Works

Once the working drawings are complete, we would also recommend that a written specification is also prepared for your project as this will minimize misunderstanding between you and your chosen builder/supplier.

There are many aspects of your project that will not necessarily be shown on your drawings (e.g. type of ironmongery, floor tiles, etc) but these need to be defined so that a builder can properly quote for the works. The specification will also usually form part of your agreement with the builder when works commence.