How Much Does It Cost For An Extension?

by | Last updated on January 24, 2024

, , , ,
Type of extension Highest average price Lowest average price
Single room


$78,000


$17,000
Same level $150,000 $40,000 Multi-level $350,000 $100,000

How much does an extension cost in Australia?

How much does a house extension cost? According to assessment experts and design architects Archicentre Australia, an extension to an existing building could cost from

$1,900 to $3,600 per square metre

.

How much does an extension cost Ireland?

Although building costs varied across counties and regions, build type and standard of finish, the survey revealed a national average home extension cost of

€1,064 per square metre

based on a single storey extension – up by 8% since we last reported in 2016.

Is it cheaper to build up or out?

When it comes to budgeting for your home renovation, it’s important to understand the range of costs involved in building up versus building out. B

uilding out is significantly less expensive than building up

. On average, it costs between $140 to $180 to expand your home’s footprint outwards.

Do I need an architect for an extension?


For a full planning application you will need professional architecture drawings, so the answer would be Yes

. Although Permitted Development applications require a sketch and letter of intent, an architecture drawing is better because from a sketch your builder could go over by 5cm, thus risking an enforcement.

Does an extension add value?

Single-storey extensions are most commonly used to extend kitchens and/or living rooms to increase the overall amount of general living space. With open plan living being hugely popular with homeowners in the UK, single-storey extensions are a popular choice and

can often add 5 – 8% to the value of your home

.

How can I extend my house cheaply?

  1. Stick to a simple configuration. …
  2. Use simple building materials. …
  3. Plan in standard fittings. …
  4. Don’t be lured by fashionable brands. …
  5. Keep the groundworks simple. …
  6. Party Walls. …
  7. Planning Permission.

What size extension can I build without planning permission?

The recent relaxation of permitted developments means that homeowners are now able to add extensions without needing planning permissions. You can add a home extension or conservatory

up to six metres, or eight metres if your home is detached

, without needing to apply for planning permission.

How do you pay for a house extension?

  1. Home improvement loan. A home improvement loan is one option for funding a house extension. …
  2. Savings. If you have some cash to spare, then using this to pay for your house extension can make sense. …
  3. Remortgage. …
  4. Borrow more from your current lender. …
  5. Credit card.

How far can you extend without planning permission Ireland?

Extensions smaller than 40 square metres

The floor area of any extension above ground level must not exceed:

12 square metres for terraced or semi-detached houses

. 20 square metres for detached houses.

Do I need an architect for an extension Ireland?


You can build an extension without an architect

, and there are many qualified builders and experienced companies who offer such services. One of the best ways of finding an architect is through personal recommendation.

What is the cost of a single story extension?

The cost of a single storey extension will depend on the scale of your project and whereabouts you live in the country. A basic extension will typically cost you

around £1,000 per square metre

, meaning a 3×5 metre single storey extension would set you back around £15,000.

Does a bump out need a foundation?

For bump-out additions that rest on the ground,

footers and a foundation wall must be built

. Soil is dug out by hand or with a small excavator.

Is it cheaper to build a 1 story or 2 story house?

Per square foot,

a one-story house is more costly to build than a two-story home

. There is a larger footprint, meaning more foundation building and more roofing materials. And because the plumbing and heating/AC systems need to extend the length of the house, you’ll need bigger (and costlier) systems.

Can you add a story to your house?

There are many ways that additions can happen without expanding the footprint of the house:

You can add another story onto a one-story (or even a two-story) home

. You can expand an existing top floor by installing large dormers in a pitched roof to gain useful living space.

How much do architects drawings cost for an extension UK?

The cost for architects to draw up planning drawings for planning applications starts from

£5,000

for extensions and £7,000 for small scale conversions and from £10,000 for small scale new build schemes.

How much does an architect cost for an extension UK?

On average, a traditional practice will charge between 5% – 10%. For example, let’s say you’re building a classic rear extension in London and it’s expected your project will cost around £75,000 overall. If you’re using a traditional practice, you’ll need to budget

between £3750 and £7500

for your architect.

How long does it take to add an extension to a house?

A good renovation contractor will be able to expediate this process and get the permits faster. Once you’ve got all the paperwork in order, you can expect a project time of

2-3 months on an addition of 1,000 square feet

.

Is a small extension worth it?

Even if your budget is small,

a well thought-through addition to your house can make a tiny dining area more usable or create extra space for a home office

. Extensions also can enhance natural light, link existing areas of the property, and improve the overall design, letting a space breathe a bit more.

Are conservatories cheaper than extensions?

What are the costs?

A conservatory is usually cheaper than a single-storey extension of exactly the same size

.

How much does it cost to extend a house UK?

Typical costs you can expect to pay:


For a small (15m2) rear house extension the cost is around £15,000 – £20,000

. For a medium (25m2) rear house extension the cost is around £30,000 – £40,000. For a large (50m2) rear house extension the cost is around £50,000 – £60,000.

Is a house extension worth it?

Generally,

extending your home will be a cost-effective investment that will pay back on itself when you eventually sell – but not always

. The location and demand of your property will usually guarantee that your extension will add value to your home when it comes to selling.

What size extension can I build?

If you are planning and designing a single storey extension, this means it can be

up to 6m from the original rear wall of an attached house (or 8m on a detached property) and up to 4m in height

. If your extension is to be within 2m of your property’s boundary, the eaves height is limited to 3m.

How much does it cost to add a bedroom to a house UK?

Expect to pay roughly

£1,000 to £2,500 per m2 for a single storey extension and £1,500 to £2,500-plus per m2 for a two-storey extension

. There are a number of ways to add a bedroom to a dwelling but not all are feasible or financially viable.

Do you have to notify Neighbours permission for extension?

The technical term for this is called serving notice. In short if you want to make your home bigger and are attached to (or are in close proximity to) another property,

you will most likely need to notify the neighbour(s) about your extension

.

How far can you extend the back of your house?

You can extend

up to four metres at the rear of a detached home, or three metres behind a semi or a terrace house

. However, the extension must not take up more than half of the outside space and the materials used need to be in keeping with the original house.

How far can I extend to the side of my house?


If you have a detached house, the side extension must not extend for more than 4m to the rear from your original house

. If you have a semi-detached or terraced house, it must not extend for more than 3m to the rear from your original house.

David Martineau
Author
David Martineau
David is an interior designer and home improvement expert. With a degree in architecture, David has worked on various renovation projects and has written for several home and garden publications. David's expertise in decorating, renovation, and repair will help you create your dream home.