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Basement & Cellar Conversions

Transform dark, unused underground space into stunning living areas, cinemas, gyms, offices, or extra bedrooms built to the highest standard across Stockport and Cheshire.

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Unlock Hidden Space Beneath Your Home

Many older properties in Stockport and Cheshire have basements or cellars sitting unused. A professional conversion transforms this dark, damp space into a fully waterproofed, insulated, and habitable room, adding valuable square footage without any external building work.

No garden or external space used
Fully waterproofed & damp-proofed
Significant property value increase
Unique, high-spec living spaces
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Modern basement conversion with light well windows and contemporary interior

What Could Your Basement Become?

Underground spaces offer creative possibilities that other rooms simply can't match.


Home Cinema

The perfect naturally dark environment for a premium cinema room with surround sound, tiered seating, and acoustic treatment.

Home Gym

Heavy equipment on solid concrete floors, full-height mirrors, ventilation, and sound insulation, the ideal gym environment.

Wine Cellar & Bar

A temperature-controlled wine cellar with custom racking and a built-in bar area for entertaining guests in style.

Music Studio

Basements are naturally soundproofed. Add professional acoustic treatment and you have a recording or practice space.

Home Office

A quiet, distraction-free workspace completely separate from the main living areas, ideal for focused work.

Games & Entertainment

A pool table, gaming setup, or entertainment room that keeps noise and activity away from bedrooms and living rooms.

Basement waterproofing membrane installation during conversion

Why Waterproofing is Everything

The single most important aspect of any basement conversion is waterproofing. Without a properly designed system, moisture will destroy finishes, cause mould, and make the space unusable.

Type A, Barrier Protection

A waterproof coating or membrane applied directly to internal walls and floor. Suitable for dry basements with minor damp issues.

Type B, Structurally Integral

The structure itself (reinforced concrete) provides waterproofing. Usually only for new-build basements.

Type C, Cavity Drain (Most Common)

A studded membrane creates a cavity between the wall and the new internal surface. Any water that penetrates is channeled to a sump pump and removed. The gold standard for existing basements.

The Basement Conversion Process

Converting a basement is a specialist project. Here's how we approach it step by step.


1

Survey & Assessment

We inspect the basement's condition, measure headroom, assess damp levels, and determine the best waterproofing system for your property.

2

Design & Structural Engineering

Architectural drawings prepared, structural calculations completed (underpinning, floor lowering if needed), and building control application submitted.

3

Structural Work

Underpinning or floor lowering (if required) to achieve full head height. This is the most labour-intensive phase and is carefully managed to maintain structural integrity.

4

Waterproofing

Installation of the chosen waterproofing system, typically a cavity drain membrane with sump pump. This protects the space permanently against water ingress.

5

Fit-Out & Finishing

Stud walls, insulation, electrics, plumbing, plastering, flooring, lighting, and decoration. Your basement is transformed into a finished, habitable room.

Basement Conversion Costs

Basement conversions are more complex than other conversion types, but the results are transformative.

Basic cellar conversion (existing headroom)£25,000 - £40,000
Full basement with underpinning£50,000 - £80,000
High-spec finish (cinema, gym, bar)£60,000 - £120,000+
Typical value added25 to 30%

Every basement is different. We provide a detailed fixed-price quotation after our free survey and structural assessment.

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Cheadle Construction team assessing a cellar for conversion

Basement & Cellar FAQs

Essential answers about basement and cellar conversions.


Do I need planning permission for a basement conversion?

Converting an existing basement or cellar within the existing footprint usually doesn't require planning permission. However, if you're excavating to create a new basement, extending the existing one, or adding light wells, you may need planning approval. We check this for every project.

How long does a basement conversion take?

A simple cellar conversion takes 8 to 12 weeks. A full basement conversion with underpinning or floor lowering takes 12 to 20 weeks. Complex projects with high-spec finishes (cinema, gym, bar) may take longer. We provide a detailed programme at the start.

Will the conversion be damp?

Absolutely not. Our waterproofing systems are fully guaranteed and designed to handle the specific water conditions of your property. A properly waterproofed basement is drier than most above-ground rooms.

Can I add light to a basement?

Yes. Light wells, sun pipes, and carefully designed LED lighting can make a basement feel bright and airy. Many of our conversions receive more natural light than you'd expect, especially with front or rear light wells.

Is my cellar deep enough to convert?

You need a minimum of 2.4m floor-to-ceiling height for a habitable room. If your cellar is shallower, we can lower the floor level (underpinning) to achieve this. We assess feasibility during our free survey.

Ready to Unlock Your Basement?

Book a free basement survey and get a specialist quotation. We'll assess your space and tell you exactly what's possible.