How to successfully build on a large garden site
Key considerations include consulting neighbours and felling mature trees
Don’t lose the plot. The rules regarding how much space you can build on are not exact but, not surprisingly, a new house cannot take up all of the garden. Photograph: iStock
If you have a large garden with space for development, getting planning permission for a new home will significantly increase the value of your plot. Not only is developing your site a great way to maximise the value of what you have but if you decide to go ahead and build, it could provide a home for sale, for yourself or for a family member.
Building a second house on a garden plot is a particularly appealing option for downsizers. It allows them to downsize to a newly built, state of the art home without the upheaval of leaving the location and neighbourhood they have grown accustomed to. If you are thinking about this kind of development here are some of the key considerations:
How much space do I need?
There are no exact rules about the size of the plot needed to build on. But the private external space of both the existing and the new houses needs to achieve a certain minimum. In other words, the new house cannot take up all of the garden space.
There also needs to be enough space to allow clear, safe access from the main road and adequate car parking space for both the existing and new house.
If you’re thinking of developing towards the side of your home, then maintaining the look and rhythm of the houses on the street will be an essential consideration for the planners. One of the main reasons for garden plot schemes being refused planning permission is because they look too cramped on the site.
Do I need to match the existing architecture?
This is a subjective area and depends on the particular tastes of the planning department and in many cases, the individual planner dealing with your application.
The planners will look for a design that complements the existing architecture of the street or area. This doesn’t mean you have to copy the style of the neighbouring houses. In many cases, contemporary homes are welcomed by the planners, even in areas where period homes are the norm.
Run a planning search to see if you can find any similar applications in your area. Precedent is an excellent indication that what you are hoping to do will be approved. If a neighbour has already done something similar, your chances of being granted planning permission are greatly improved.
Are there any constraints regarding neighbouring houses?
Overlooking is frowned upon by the planning department. This means your new house cannot have windows that look directly into your neighbours’ windows or garden.
There are minimum allowances set out by the councils for separation distances between neighbouring properties.
In general, a minimum distance of 22 metres between opposing above ground-floor level windows is called for. A separation distance of 35 metres should be considered in the case of living room windows and balconies at upper floors.
There are design solutions to deal with many of these privacy issues. For example, orienting windows to avoid overlooking, or using obscure or high-level glazing to prevent or limit views.
Can I get rid of mature trees?
Many trees are protected by tree preservation orders which means that, in general, you need the council’s consent to fell them or even prune them.
If your home is in a conservation area, additional rules will apply. You will need to refer to the government planning guidance on tree preservation orders and trees in conservation areas.
If you are unsure about the status of trees that you intend to prune or fell, you should contact your local council. You will also need a tree survey as part of your planning application.
Even in cases where trees are not protected, cutting them down can cause problems for neighbours when developing a garden plot. Especially where the trees form part of an attractive streetscape or windbreak.
Working with a landscape architect to create a new landscaping plan is a worthwhile investment and in many cases can help to prevent any objections to the removal of trees on your site.
Should I consult my neighbours?
As with any kind of development to your home or site, it’s important to consult with your neighbours prior to making the planning application. Having the support of your neighbours from the outset will mean that you are more likely to avoid objections to the proposed work.
Avoiding objections is always desirable because not only will you maintain your good relationships with the people you live beside but you will also avoid the potential risk of lengthy delays to your project should it go to An Bord Pleanála.
Denise O’Connor is an architect and design consultant @optimisedesign