Double Storey Extensions
Maximise your home's potential with a two-storey extension, adding bedrooms, bathrooms, and living space in one transformative build across Stockport and Cheshire.
Double the Space, Double the Value
A double storey extension adds significant space on both floors in one project. For a modest additional cost over single storey, you gain an entire extra floor, one of the most cost-effective ways to transform your home.
Why Go Double Instead of Single?
20m· new space
From 35,000
1,750/m
40m· new space
From 55,000
1,375/m
Double storey extensions offer a lower cost per square metre because foundations and roof costs are shared across two floors.
What You Can Achieve on Each Floor
A double storey extension gives you the flexibility to create completely different rooms on each level. Here are the most popular layouts our clients choose.
The most popular ground floor use, a large, open kitchen, dining, and living area with bi-fold doors to the garden.
A separate, spacious living or family room, ideal for play areas, TV rooms, or a cosy second lounge.
A dedicated ground-floor workspace or a utility room with laundry facilities, storage, and a WC.
A large master bedroom with a luxury en-suite shower room or bathroom, the most requested first-floor layout.
One or two extra bedrooms for growing families, guest rooms, or renting, significantly increasing property value.
A new full-size family bathroom or shower room to complement the additional bedrooms on the upper floor.
The Engineering Behind Two-Storey Builds
Double storey extensions involve critical structural engineering that requires specialist expertise. The additional weight of a second floor places greater demands on foundations, walls, and steel support structures. This is where our 20+ years of experience makes a real difference.
Two-storey extensions require deeper, wider strip or trench-fill foundations to support the increased load, typically 1m+ deep depending on ground conditions.
Structural steel beams (RSJs) support openings in load-bearing walls and transfer the weight of the upper floor. We work with chartered structural engineers on every project.
Full cavity wall construction with 100mm insulation cavities, wall ties, and DPC to achieve thermal performance beyond current Building Regulations.
Careful tying-in of the new roof structure with the existing property, matching ridge lines, valleys, and tiles for a seamless finish that looks original.
Planning Requirements for Double Storey Extensions
Unlike many single storey extensions, double storey extensions almost always require full planning permission. Here's what you need to know.
Full Planning Required
Most two-storey extensions exceed permitted development limits and require a full planning application. We prepare and submit all planning documents, drawings, and supporting statements on your behalf.
Key Restrictions
Two-storey rear extensions must not extend more than 3m from the original rear wall. They must be at least 7m from the rear boundary. No first-floor side-facing windows overlooking neighbouring properties without obscured glazing.
Neighbour Considerations
Double storey extensions have greater impact on neighbours' light and privacy. We design to minimise objections, address overlooking concerns, and manage the planning process to maximise approval chances.
Building Regulations
All double storey extensions require Building Regulations approval covering structural stability, fire safety, thermal insulation, sound insulation between floors, drainage, and staircase design.
How Much Does a Double Storey Extension Cost?
A double storey extension in the Stockport and Cheshire area typically costs between 55,000 and 120,000+ depending on size, specification, and complexity. Here's a breakdown of typical costs:
We provide a detailed, fixed-price quotation after our free site survey. No hidden costs, ever.
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Double Storey Extension FAQs
Answers to the most common questions about two-storey extensions.
How long does a double storey extension take?
A typical double storey extension takes 16 to 24 weeks from breaking ground to handover. This includes groundworks, structural build, roofing, first fix, second fix, and finishing. Larger or more complex projects may take longer. We provide a detailed programme of works at the start.
Can I extend to the side as well as the rear?
Yes, many of our double storey extensions combine rear and side elements to create an L-shaped or T-shaped extension. Side extensions on the first floor must comply with specific planning rules about proximity to boundaries and windows overlooking neighbours. We design to meet all requirements.
Will the extension match my existing house?
Absolutely. We source matching bricks (or the closest available match), use matching roof tiles, and design the roofline to integrate seamlessly with your existing property. The goal is for the extension to look like it has always been part of the original building.
Do I need to move out during the build?
Most of our clients stay in their homes throughout a double storey extension. We carefully phase the work to maintain access to bedrooms and essential facilities. However, for very large extensions or where existing bedrooms are being significantly altered, a short period away may be more comfortable.
How far can a double storey extension extend?
Under current planning rules, a two-storey rear extension must not extend more than 3 metres from the original rear wall, and must be at least 7 metres from the rear boundary. There is no prior approval route for double storey extensions, full planning permission is always required.