Extensions – The Wiggs guide to getting a home extension


Extensions – The Wiggs guide to getting a home extension


The Wiggs Guide to extending your home

Extending the footprint of your home is by far the most popular way to add space without having to move. In this guide the team at Wiggs will aim to  explain everything you need to know about extensions, from getting planning permission to potential costs and more.

Why Extend Your Home?

Perhaps the biggest advantage to extending and not moving to a larger house is avoiding stamp duty. Agents fees, the dreaded stamp duty and the stress of moving house can all be avoided by employing a trusted local builder to extend your home, and probably for a lot less than you might imagine.

Obviously it’s important to put a lot of thought into even the smallest of extensions, and we always advise our clients to make sure they’re benefitting from an extension as a financial investment as well as benefitting from the increased living space. Always consider what you’re looking to achieve with an extension and look at the impact the building work will have on everyone involved.

Look closely at the practical issues that are involved, even the ones that are not directly concerned with the construction process. Is access to the site easy? Will any additions to the house cause an impact for your neighbours? Consider everything closely before you instruct a builder and then use a builder with experience in your particular property. At Wiggs we have a huge amount of experience in extending and renovating properties in the Herts, Essex, Beds and Bucks areas – and as a result we can show you loads of examples of where we had to overcome difficult technical issues. Make sure your builder is experienced in dealing with your style of home and in your area.

How much do extensions cost?

Quite rightly, this is usually the first question our customers ask us and to be honest the answer is usually: It Depends! There are a huge number of variables involved that will affect the cost of your extension.

  • What is the soil type of the site? (This impacts the foundations)
  • Are you planning a single or two storey extension?
  • Will it be timber framed or brick and block?
  • What the extension will be used for?
  • How much glazing you plan to specify?
  • What level of fit and finish do you want internally?

Generally speaking, two storey extensions don’t cost much more per square metre than single storey, because, aside from the extra interior fixtures and finishes, you are only adding walls and floor joists — a roof and foundations are required whether your extension is single or two storey.

Will I Need Planning Permission for my Extension?

Generally speaking yes. However, under the Permitted Development Rights system a large number of home extensions can be built without the requirement of planning permission. But always speak to an experienced builder who will know and can recommend an experienced, trust worthy architect.

  • You can extend a detached dwelling by 8m to the rear if it’s single storey or 3m if it’s double.
  • There are height restrictions: A single storey extension not being higher than 4m in height to the ridge and the eaves, and ridge heights of any extension not being higher than the existing property.
  • Two storey extensions must not be closer than 7m to the rear boundary.
  • It must be built in the same or similar material to the existing dwelling.
  • Extensions must not go forward of the building line of the original dwelling.
  • Side extensions must be single storey, maximum height of 4m and a width no more than half of the original building.
  • In Designated Areas side extensions require planning permission and all rear extensions must be single storey.
  • An extension must not result in more than half the garden being covered.
  • You can only do it once and the original building is either as it was on 1st July 1948 or when it was built.

If your house is in a Conservation Area or a National Park, the amount of work one can do under Permitted Development is usually much reduced.

Extensions – Building Regulations

All structural changes to any property require Building Regulations Approval (MORE INFO HERE). These are essentially rules approved created by Parliament to ensure the minimum design and construction standards are achieved and adhered to. They cover everything from  fire and other forms of safety, through to insulation, drainage & sewerage and access.

In order to meet Building Regulations (often called ‘Building Regs’) you can either send a full plan submission to your local authority, or submit a Building Notice, which is essentially a statement to inform the Local Authority that you will be commencing building your extension and complying with the regulations in place. This must be done 48 hours before commencing. In this case surveyors will visit the site at various times to ensure you are complying with the regulations. This second option, although easier initially, comes with a significant risk as you will not have the benefit of an approved plan of works. It can be an expensive exercise if build problems are discovered that have to be put right. At Wiggs we nearly always recommend the full plan submission as it gives us and our clients the benefit of an approved plan to work from.

Extensions – Employing an Architect

All extension or alteration projects will benefit from the expertise of an Architect. Whether that is a fully qualified Architect or an Architectural Technologist will depend on the scale of the project. At Wiggs we have close ties with several local Architecture Practises that we have been working with for years, and thoroughly recommend. It is important that you find an Architect that is the ‘right fit’ for your project and who essentially gets exactly what it is you’re looking to achieve. Like many professions, you will find that some architects are better than others and importantly, some simply have a better understanding of what it is you’re trying to achieve. Our advice is to take your time finding an Architect or speak to us about who we recommend and why.

Further help

If you would like any further help with your project, please don’t hesitate to call or email us. We’re happy to talk to you about your project and will always give as much advice as we can. Good luck with your projects!



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