15 two storey extension design ideas

Find inspiration for your own two-storey extension with our pick of the best design projects

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Considering a two storey extension and looking for design ideas? Adding two storeys will give you lots of space and value and could be a cheaper option than moving. In addition, a two storey extension proves particularly cost effective, which means it could be worth upgrading a planned single storey extension to one with two floors.

From traditional style oak framed extensions to glass box extensions and everything in between, find inspiration for your own two-storey extension with our pick of the best design projects. 

Want more practical advice? Don't miss our guide to planning and building a two storey extension.

1. Add a two storey, rustic oak frame extension

The owners of this stone-built farmhouse, located in a small town between Carmarthen and Lampeter in west Wales, tasked oak frame design-and-build specialist Arboreta with creating more space. The oak frame extension was designed to take in views with a sunroom downstairs and bedroom above. 

Lots of glazing was incorporated while maintaining a look that was sympathetic to the period style of the home. A similar oak-framed extension would cost around £35,000.

Find out how to build an oak frame extension and use these oak frame extension design ideas for inspiration.

Arborita extension

2. Choose a contemporary two storey glazed extension

If you're building down into a basement, a glazed extension will make the most of light – and will enhance the space, particularly if the extension overlooks a courtyard garden that could be bigger. If budget allows, choose wide expanses of glazing over detailed or heavy framing; this will maximise the light indoors and create a contemporary appeal.

Find out more about designing a glass extension in our practical guide.

Glazed extension by IQ Glass

Glazed extension by IQ Glass

3. Maximise a Victorian terrace with a two storey extension

Planning a two storey extension within a narrow terraced plot can provide challenges, with neighbours, quite rightly, able to contest any plans on the grounds of their right to light. This two storey extension skirts the problem, with the walls of the upper storey well clear of the boundaries on either side of the house. 

Find out more about how to extend a Victorian house in our guide.

Sarah barker Brown and Nicolas Brown extension

(Image: © Rick Mccullagh)

4. Build a gable end to create an extra bedroom

Think about the form of your two storey extension as you're planning it. A square extension is rarely pleasing to look at – and will be overbearing for your neighbours if it stretches from one party wall to the next. Instead, introduce a gable end on the upper floor to create a better looking roofline that still offers bags of interior space.

Inside-outside extension by Riach Architects

Inside-outside extension by Riach Architects

5. Keep the extension in keeping with the original house

A two storey extension is much more noticeable than a single storey extension, so it either needs to contrast sharply (like the glazed extension above) or it needs to blend seamlessly with your existing house. This two storey extension below takes the latter approach, being built in keeping with the original, 1950s house.

Find out how to add a two storey extension without planning permission.

Anne and Duncan Westland 1950s inside-outside two-storey extension

(Image: © Martha O'Shea)

6. Use contrasting exterior materials to make a statement

If you want a contemporary finish – and particularly if you have chosen a very contemporary shape and form for your extension – picking out exterior finishes that contrast both with each other and your original house can work brilliantly. 

Read our guide to cladding and renders to work out what to choose for your home's exterior.

Brickwork contrast extension by Lipton Plant Architects

Contemporary extension by AR Design Studio

7. Choose a contrasting brickwork

This has to be done with great care – and possibly with the consent of your local council, particularly if you live in a conservation area, but it can work. Here, the bricks are the same size as the originals, and the same tone, but their different colours cleverly define the old and the new.

More more stand-out statement extensions like this, see our design gallery.

]Glass box extension by IQ Glass]

Brickwork contrast extension by Lipton Plant Architects

8. Squeeze a two-storey glass box extension into a narrow space

Want to create views from upper floors and impact at garden basement level? The solution, especially in a narrow terraced space, is to build a galleried two storey glazed extension. It will allow the existing rooms to be flooded with light but give you more indoor-outdoor living space.

Glass box extension by IQ Glass]

Glass box extension by IQ Glass

9. Go modern with a minimalist two storey extension

Architect Your Home was chosen to design this extension (below) in keeping with the street scene for this house in Surrey. The owners wanted a modern style with white rendered walls and sliding doors. Built in place of the garage, the extension creates a home office, utility room and large kitchen that opens out onto the dining room and garden. Upstairs, two new bedrooms were created.

Minimalist extension by Architect your Home

The cost: In total, this project cost around £156,000

10. Create a sympathetic extension for a period property

If yours is a period home, particularly in a rustic setting, it's worth designing an extension that, from the outside at least, is entirely complementary to your existing building. This can be achieved with matched materials, a roofline that flatters that of the original house, and windows and doors picked to blend with the originals.

For more extension ideas for period homes, check out our design gallery.

Eco-friendly extension by Samuel Kendall Associates

Eco-friendly extension by Samuel Kendall Associates

11. Connect two buildings with a glazed extension

To connect the two distinct areas of their Swansea home, the owners commissioned this extension (below) in the form of a glass atrium from Apropos. The stunning double-height design mirrors the roof pitch of the main building sections, to bridge the two wings of the house. The light-filled space is used as an entrance hall and quiet living area that allows the garden to be enjoyed all year.

This is a solution that can please planners when you're looking to connect two existing period properties.

Atrium extension from Apropos

A similar structure would cost around £150,000 for design, planning permission, materials, manufacturing and installation

12. Create a two storey garden room

A desire for more living space led the owners of this Bristol property to contact Vale Garden Houses, which created an extension that adds a garden room off the existing downstairs living space and an enlarged kitchen-diner above; a roof lantern ensures the room is filled with natural light. Local stone was sourced to match the main building, with traditional timber used for the frame, incorporating decorative mouldings and classical columns. Sliding sash windows ensure continuity with the existing house.

Find out more about planning and designing an orangery style extension with our guide.

Garden room extension by Vale Garden Houses

Expect to pay £42,000 for a similar garden room extension from Vale

13. Choose a stand-out exterior cladding for impact

Using a metallic cladding will give even the most ordinary of two storey extensions a highly contemporary, smart finish. However, this needs to be done with caution – particularly because some finishes can be extremely expensive, and will give your house a distinctly different feel from others in the street. So, before you proceed, consult a trusted estate agent to find out if making your house stand out so strongly might damage its value.

Find out more about choosing the right exterior finish for your home to get yours right.

Metallic finish extension by Des Ewing Residential Architects

Metallic finish extension by Des Ewing Residential Architects

14. Be clever with a slim, two storey extension at the front of a house

It's not always easy to get planners to give you planning permission for an extension that's visible at the front of your house – and particularly a two storey extension. This clever clad contrast seems to have passed muster, though, giving the home it's attached to a contemporary update. 


Slimline extension by Waind Gohil

15. Two storey extension window know how

When you're extending upwards and outwards, it's easy to be distracted by rooflines and floorplans and not give quite enough thought to windows and doors. Bifold or sliding doors downstairs to merge the garden and the new extension are a given, but don't neglect to give lots of thought to the design of the windows upstairs, too. 

Here, the windows have been successfully designed to both flood the interiors with light and to create a visual impact from outside. 

Two storey extension with white render

16. Create a sculptural two storey extension

What to say about this striking two storey extension? It has bags of glazing, concealed upper windows and a sculptural appeal. Genius.

Sculptural timber extension by Paul Archer Design

Sculptural timber-clad extension by Paul Archer Design

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