Rear extension ideas for semi detached houses

a sEMI DETACHED EXTENSION - IMAGE: @samanthajonesathome

Layout idea for a sEMI DETACHED EXTENSION - IMAGE: @samanthajonesathome

If you’re looking for extension ideas for semi detached houses you’ve come to the right place. The potential to extend with a semi-detached house is almost endless. With only one adjoining wall, you’ve got the possibility to add a side extension, rear extensions, loft conversions or even wrap around extensions or garage conversions.

And the choices you make around your extension can add some serious square meterage to your property, open up new social spaces, create multiple new rooms or even just let some extra light into an expanded room. 

But of course, you have to work within the parameters of what is allowed under permitted developments or planning permission and the space you’ve got with your existing dwelling. So, we’ve gathered a whole range of extension ideas for semi detached houses to inspire the direction, style, shape and use of your extension project. 

A rear EXTENSION idea on a semi detached house- IMAGE: @no.fifty.two

1. Extend as far back as possible

If you’re lucky enough to have ample space at the rear of your dwelling, then extending to the back can create so much more, it could almost double your floor space.

We love how this extension has been done very tastefully so it blends in seamlessly with the existing dwelling and you can barely notice it.

This extension looks to have created at least two more substantial rooms which is quite impressive!

Idea for mATCHING AN EXTENSION TO YOUR semi detached property - IMAGE: @project_19x

2. Coordinate your extension

If there’s one sure-fire way to make a rear extension blend seamlessly with your original property, it’s by coordinating your roof and render.

The benefits of a coordinated extension are both practical and aesthetic and we’re wondering why this isn’t done more often.

It might mean taking on a larger renovation job but it’ll be totally worth it for the finished look.

semi detached extension ideas

Semi detached sLOPING ROOF idea for an EXTENSION - IMAGE: @thegirlbosshouse

3. Try a small sloping extension

When it comes to extensions, we’ve always got to work within the boundaries of the dwelling and land we’ve got. And sometimes budget or requirements means just a small extension will suffice.

We love how this home has extended their square footage amply but just extending backwards a couple of metres and coordinating the brickwork and roofing styles to the existing structure to create a small but significant addition. 

semi detached extension ideas


4. Let the light into your extension

This structure is simply fantastic.

We love how the homeowners have used the normal roof structure to recreate the feeling of being in a lofty open space and the heavy use of Velux windows works so well to let all that natural light in.

Putting the kitchen in the big space also makes a really nice change as it makes the whole space a hub in the home and opens up such a social opportunity for interaction. 

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semi detached extension ideas

semi detached LEAN TO EXTENSION idea - IMAGE: @aliceinscandiland

5. Make your extension a garden room

This kind of structure remind us of all the light and openness of a greenhouse but still has the secure structure of a home extension.

We love how this kind of extension really embraces building into the garden and welcomes in the best of the outdoor elements also it makes for such a great lifestyle change in the home.

The hidden bonus of this extension idea, other than opening up a semi-detached house, is that it tends to cost less than a bricks and mortar construction so can be more budget-friendly.

semi detached extension ideas

fULL WIDTH EXTENSION idea for a semi detached house - IMAGE: @no3_home_reno

6. Go full width with your extension

If your perimeters allow then choosing to build a full-width with your extension can create a huge amount of new floor space and doesn’t detract from the garden if you’ve got one big enough.

Taking up the full space you’ve got can double your ground floor square footage with a semi of this size and also makes for a nice contrast between architectural styles.

As a bonus, attaching a porch to the rear of your extension means you’ve got a great summer social space and expands your home even further.

semi detached extension ideas

semi detached PITCHED ROOF AND FLAT ROOF EXTENSION idea - IMAGE: @samanthajonesathome

7. Change up your roof shapes

If you’re going for a large scale rear extension across the width of your property then changing up architectural styles across pitched and flat roofing makes a profound effect visually.

This kind of extension design also means you can separate into two or more rooms and we love how this home has left the eaves of the pitched roof as a window to let extra light in.

an idea for a rear extension on a 1930s semi detached house - IMAGE: @edge_invested_properties

8. Try a rear extension in two parts

Rear extensions don’t need to be limited to just a single room.

Depending on the rear of your property, you can get so much more out of your extension by opting for two parts to your plan, working both a strip at the rear but also a larger room out to the side.

This looks amazing with a semi particularly because it looks like it simply blends in with the rest of the house.

semi detached flat roof extension idea - IMAGE: @no23andme

9. Extend with a simple flat roof

Sometimes a simple, flat roofed, single-room extension is all you need to transform inside your home.

These homeowners have made sure they avoid the common mistakes of this kind of room being dark by using big bifolds to make sure the light keeps streaming in.

We also love how they’ve coordinated with the existing dwelling to tie the whole thing together visually. 

semi detached extension ideas

L-Shaped Extension idea in a semi detached house - IMAGE: @newroad_newproject

10. Go long at the back

So many semi-detached houses have nice, lengthy gardens which make for a huge opportunity to build into.

This home has decided to go long-ways with a big L-shaped extension and created a huge amount of new space.

If you click through to the original post, they’ve totally transformed a small, old house and extended it into something so much bigger and it all blends in perfectly. 

Rendered 1930s rear semi extension idea

rendered 1930s semi rear extension idea - image: @royceson_country_renovation

11. Jazz up your exterior with render

Sure, we love the typical old red brick in a 1930s semi, but it can look absolutely smashing going with contrast for your rear extension.

The home pictured here has built a huge extension, spanning over two floors and really quite wide.

With something this big, you can mix it up the exterior finishes and create something new whilst it still looks at home with the original structure.

L-shape 1930s rear semi extension idea

L-shape 1930s semi rear extension idea - @renovatingthebroadway

12. Go wide and wrap around

With a semi, you’ve usually got a bit of space to work with at the side.

These homeowners have built out to the rear and wrapped around to the side so they’ve maximised the extra added floor space and still made it look stunning.

We also really like how they’ve used a hefty rear patio to work between the different ground heights to the back of the house.

Decked 1930s semi rear extension ideas

Decked 1930s rear semi extension idea - image: @growingchestnut

13. Use your extension to open out into the garden

When you’re building your own 1930s semi rear extension, you’ve got the perfect opportunity to incorporate larger, more expansive doors which can transform how you use your garden/

The home pictured here has fitted a deck which stretches back into the garden so they’re really extending the living and entertaining space, especially for the warmer months.

Bifolds really can work wonders in a rear extension!

Timber clad 1930s semi rear extension idea

Timber clad 1930s semi rear extension idea - image: @halstead_House_build

14. Timber cladding looks amazing

Brickwork? No. Render? No.

Go with some spectacular-looking timber cladding to make your rear extension quite distinctive.

This idea works really well with flat roof extensions and creates a nice contrast between the 1930s look of the main home and something contemporary in the extension.

Colourful 1930s semi rear extension

Colourful 1930s semi rear extension idea - image: @two_guys_at_glenlyn

15. Work with colour!

If you’re trying to figure out a way to tie your extension to your existing home but don’t want to re-tile the entire roof, consider working colour across the two.

The home pictured here has used this stunning shade of green to tie a long rear extension to the rest of their 1930s semi and popped a black timber section around the two, too.

This way, you don’t need to re-finish both buildings just to make them coordinate and it looks great!

Are you on your own semi-detached house renovation journey? Have you extended? What kind of structure did you go for? Or do you have big plans for your renovation? Let’s get chatting!

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