10 ways to cut the cost of your home extension

I am in the middle of building our family home extension in Dublin, oh boy it’s not that easy if your budget is tight. It can be very costly to build extension. Most prices range from €45,000 to €80,000 but they can go up as far as €130,000. Building costs have risen by 15 per cent in recent years. If your budget is tight to maximize value without compromising on quality check out this essential advice.

1.Pick a simple design. Curves, folds and complicated shapes are costly to build, so keep your extension as simple as possible. A square or rectangular footprint with a pitched roof will be cheapest. You can add roof lights to the pitched roof to help bring natural light into new space. Use a simple palette of materials: cast concrete for the sub-floor, concrete block work for the walls; brick, render or timber cladding; and a timber roof. Build away from trees and drains to avoid costly groundwork.


2. Manage the project. A builder will add around 20-40 per cent onto the total cost to cover their time for managing the project. You can save some of this by taking on the role yourself. This will mean dealing with your designer/architect and your local authority’s Building Control Dept.; finding and hiring tradespeople; directing the work and supplying materials; plus, organizing skips and scaffolding etc. It is time-consuming but can be rewarding.

3. If you can, DIY. Labour costs represent between half and two-thirds of the outlay for a typical extension-if you can do some of the works yourself, there is chance to make savings. The easiest tasks to take on are decorating and landscaping, followed by some of the “second fix” trades, such as kitchen fitting, tiling, coving and skirting boards, painting. Unless you are an expert, hire professionals for the skilled work where the results will always be on view.

4. Save on VAT. Most extensions work will attract VAT at 23 per cent on labour and materials, but if you use self-employed tradespeople who each turnover less than the threshold for VAT registration, you will not be charged this tax-saving on labour costs. Second-hand materials sold by private individuals on the internet will also be free of VAT.

5. Find the best trades. To avoid being ripped off, always tender for your project and ask at least three tradesmen for detailed quotes and references, advises, qualifications and insurance details. Agree payments at set stages. Only pay for each stage as it’s signed off by the certifier. Never hand over money for materials in advance-if a builder does not want to supply materials, buy them yourself.

6. Get the plans right before the start. Any extras must be fully priced by the builder and agreed in advance of execution on site. One way to avoid extras is to ensure that everyone involved is clear from the beginning what is required from the build. The old saying “draw four times, build once” is very true and wise. Get the plans right before the start. If you have a partner, make sure you are both in agreement on the fine detail and avoid the builder having to price work while on site. Even the most conscientious of builders love the word “extra” when they are in the middle of a job.

7. Work out your windows.Glazing is another area where you can compromise. This can be an expensive aspect of the build, so use a mixture of aluminium and uPVC cleverly. Bi-fold doors over a certain size should be aluminium, but windows can be uPVC to keep costs in hand. It’s key to be realistic with your budget, as glass is more expensive than traditional materials, such as bricks and block work, especially when working with large, bespoke sizes. If you’re trying to maximize the amount of glazing while keeping the costs down, look into openings and skylights that come in standard sizes. You’d be surprised at the effect a large roof window can have on your room, and, if finished well, it certainly doesn’t have to look like the budget option.

8. Negotiate trade discounts. Find out where tradespeople buy their materials and aim to get the same            wholesale/trade prices. Check if there are any discounts. Buying end-of-line deals will save you a fortune,            especially on items as tiles, carpets, units and appliances. Check the deals on Donedeal. Getting the best deal will often mean moving away from the brand names and finding equivalents without the price premium.

9. Reuse, recycle and repair. Existing materials can be reused or sold rather than thrown in a skip. Old                floorboard, doors, radiators, towel rails and kitchen units can all be revised and reused, cleaned up and              given new finish. Sell or trade what you can’t reuse.

10. Second-hand items. Buying salvaged materials can be a lot cheaper than buying new and will introduce instant character. Second-hand items that offer good value include roof tiles, bricks, internal doors, timber floorboards, kitchen appliances, cabinets. The best to get second-hand is on, Gumtree, eBay or Shpock.


I hope this helps some of you who are planning a house extension in the future whether you want to make more room for the children, kitchen, dining area, bathroom, or for a home office.