Two-Storey Extensions Liverpool

If you need more space upstairs and downstairs, a two-storey extension is the smartest investment you can make. You get double the floor area for roughly 40% more than a single storey extension, because you’re sharing the same foundations and roof structure across two floors. It’s the most cost-effective way to add both a large kitchen-diner on the ground floor and an extra bedroom or bathroom upstairs, all in one build.

At Glassar Projects, we’ve been building two-storey extensions across Liverpool for over 40 years. From the detached homes in Childwall and Woolton to the semis in Aigburth and Allerton, we understand the local housing stock and know how to design an extension that looks like it was always part of the house.

When Does a Two-Storey Extension Make Sense?

A two-storey extension is the right choice when you need space on both floors. The most common scenarios we see in Liverpool are:

Growing families who need an extra bedroom and a bigger kitchen at the same time.
Homeowners adding a master suite with an en-suite bathroom upstairs, and a utility room or home office downstairs.
Properties where garden space is limited, so building up makes more sense than building out.
Families who want to avoid moving but need significantly more space. A two-storey extension can add 40-60m² to your home, which is like adding two extra rooms.

How Much Does a Two-Storey Extension Cost in Liverpool?

Two-storey extensions are a bigger investment, but the cost per square metre is significantly lower than a single storey because you’re doubling the space without doubling the foundations and roof cost.

Extension Size	Typical Cost (inc. VAT)
Small (30m² total)	£55,000 – £65,000
Medium (40-50m²)	£65,000 – £85,000
Large (60m²+)	£85,000 – £110,000

For a detailed, fixed-price quote for your specific project, use our Quick Quote Calculator.

Our 4-Step Process

1. Design & Planning

Two-storey extensions almost always require full planning permission, so getting the design right from the start is critical. We produce detailed architectural drawings and submit the application to Liverpool City Council. We also handle the structural engineering calculations and Building Regulations application.

2. Foundations & Structural Work

Two-storey extensions need deeper, more robust foundations than single storey builds. Our groundwork team excavates and pours the foundations, then builds the ground-floor walls and installs the steel beams that will support the first floor.

3. Build & Fit-Out

The first floor is constructed, the roof is built to match your existing roofline, and all windows and doors are fitted. Our plumbers, electricians, and heating engineers run all the first-fix services on both floors. Then comes insulation, plastering, and second-fix work.

4. Finishing & Handover

We complete all decorating on both floors, fit any kitchens, bathrooms, or en-suites, and carry out a thorough clean. We walk you through everything, hand over all certificates, and make sure you’re completely happy.

Planning Permission for Two-Storey Extensions

Unlike single storey extensions, two-storey extensions almost always need full planning permission from Liverpool City Council. The key rules are:

The extension must not be closer than 7 metres to the rear boundary.
The ridge height cannot exceed the existing house.
Materials should match the existing property.
The extension must not overlook neighbouring properties (obscure glazing may be required on side windows).

We handle the entire planning process for you, including producing the drawings, writing the design and access statement, and liaising with the planning officer. Our approval rate is excellent because we design extensions that planners are happy to approve.

Neighbourhood Spotlight: Woolton

Woolton is one of our favourite areas to work in for two-storey extensions. The generous plot sizes and mature gardens mean there’s usually plenty of room to extend without getting too close to the boundary. The 1930s and 1950s detached and semi-detached houses in Woolton Village, along Menlove Avenue, and around Woolton Park are ideal candidates. A typical Woolton two-storey project gives the family a large kitchen-diner downstairs with a new master bedroom and en-suite above. The result is a home that feels twice the size, without losing the character that makes Woolton properties so desirable.

Frequently Asked Questions

1. Do I always need planning permission for a two-storey extension?

In almost all cases, yes. Two-storey extensions do not fall under Permitted Development in the same way single storey extensions do. You will need to submit a full planning application to Liverpool City Council. We handle this entire process for you.

2. How long does a two-storey extension take?

A typical two-storey extension takes 16-24 weeks from breaking ground to completion. More complex projects with high-spec finishes may take longer. We provide a detailed week-by-week programme before we start.

3. Can I build a two-storey extension on a semi-detached house?

Yes, absolutely. Two-storey extensions on semis are very common in Liverpool, particularly in Childwall, Allerton, and Aigburth. The key consideration is the 7-metre rule (distance to the rear boundary) and ensuring the extension doesn’t overlook your neighbours.

4. Will a two-storey extension add value to my home?

A well-designed two-storey extension typically adds 10-15% to your property’s value. In Liverpool, where average house prices range from £180,000 to £350,000 depending on the area, that could mean an extra £25,000-£50,000 of value, on top of the extra living space.

5. Can I match the brickwork to my existing house?

Yes, and we always aim to. We source matching bricks and roof tiles so the extension looks like it was always part of the original house. For older properties in Mossley Hill or West Derby, we work with specialist suppliers to find the closest match.

6. What about the staircase? Do I need a new one?

In most cases, we extend the existing landing to connect to the new first-floor rooms, so you don’t need a new staircase. The upstairs layout is designed to flow naturally from your existing landing.

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