Building an Extension – What you need to know

Building an extension is often the best way to add some extra space without moving house.

It’s cost-effective and makes sense if you have the space on your site, but there are several factors you need to consider before you start. Follow our easy guide to building an extension and your addition is sure to give your home a new lease of life:

Will I need planning permission for my extension?

You probably won’t need planning permission if the extension you are building is at the back of the house, increases the original floor area of the house by less than 40m2, and does not increase the height of the house. When the extension is completed, the rear open space available solely for the residents’ use should still be at least 25m2. If the house has been extended before, the area of the existing extension combined with the new extension should not exceed 40m2. (There are also other height restrictions.)

If your project falls outside these criteria, you will need to apply for planning permission to the Planning Department of your local authority.

Your budget & how to allocate it

Prices vary hugely across the country, so be sure to shop around before you agree a quote. Don’t be tempted to cut corners, however, given that you may be living with this extension for the rest of your life. Based on recent figures, prices for an average 40m2 single-story rear extension with an apex roof finished to a good standard and ready to furnish start from €55,000(€62,425 incl. VAT) to €80,000(€90,800 inc. VAT,) but they can go up to €110,000(€124,850 incl. VAT).  Dublin averages are more expensive.

Getting the best price:

Get at least three quotes from three different contractors for the work. It is helpful at this stage to get an architectural professional to create a design and specification for you that you can present to prospective builders. List everything you want included in your extension, so that when you get the quotes back, you can compare the costs for each individual element. Ensure that VAT is included in the costs. Also bear in mind that the cost of a two-story extension will not differ much from a single-story addition because the foundations absorb most of the cost. Allocate an additional 10 percent for unforeseen costs.

Before you select your contractor, get references, qualifications, and insurance details.

Financing your extension

If getting a mortgage or a top-up loan from a commercial lender is not an option, try the credit union. Before you approach your lender, make sure you have detailed drawings of the proposed extension completed. Your architectural professional will help you with this.

You will also need to bring a copy of the planning permission (if required) and your building cost estimate from your architectural professional or quantity surveyor.

Keeping on Budget

Sign a contract with your builder to keep costs under control. The Royal Institute of the Architects of Ireland (RIAI) have a number of different contract types. Confirm a stage payment schedule with your builder that matches the drawdown schedule agreed with your lender. Get your professional to certify each claim/invoice as a reasonable reflection of the amount of work completed at a given date.

Your insurance provider

It’s easy to overlook your insurance, but it is important to inform your home insurance provider of your extension plans before you start. The addition will increase the rebuild cost of your home, which means the buildings cover may have to be increased. Building work also increases the risk of damage to the property, which is something your insurance company needs to be aware of and may increase your premium. If you don’t inform your insurer, and something happens, you may find that your insurance policy does not cover you. Make sure your builder has professional indemnity insurance to cover you in case of anything going wrong during the build.

Check out our resources page on our website for the Design Guide – 13 steps to planning a successful building project for homeowners

Your neighbours

Make life easier for yourself by keeping on the good side of your neighbours. That means you should inform them of your plans before you start—especially if planning permission will be required. You don’t want their first indication that anything is happening is a site or newspaper notice.

Are you considering a flat-roof extension? You will not be allowed to use that roof as a balcony with handrails because it could lead to overlooking and privacy issues.

Note on Party Walls

A party wall is a wall shared between two properties. In Ireland, party walls are covered by the Land and Conveyancing Law Reform Act 2009, which describes the rights of an individual proposing to carry out works and the rights of the person living next door.

Designing your extension

It is important to give as much information to your architectural professional as possible. Please refer to previous Blog Post on developing a brief. They will need to know everything you want your extension to do, as well as desired finishes and materials, your timings, and, of course, your budget. You will need to consider things like aspect: If it’s a kitchen extension, do you want it to face the morning sun, for example.

You will save money if you know which products you can source yourself. Sourcing your preferred windows, doors, kitchens, tiles, and other materials at the right price can take time, so deciding on these in advance will help the design process and keep costs down. Your architectural professional will be able to advise you.

As well as an architectural professional, you may need a structural engineer for specifying steel or other elements, and you will need a building energy assessor if you’re considering an energy upgrade.

Ready to get a start on building your extension? Talk to us at JS Design Architectural Solutions and we will help you create that extra space that will complete your home.