Loft Conversions
Stunning Loft Conversions in South London.
Family run craftsmanship
We're a family business and involved in every project from start to finish so you always have a friendly team on hand and a quality finish.
End to end support
We work on the project from idea and planning through scaffolding and plumbing all the way to the final finishing touches.
Fixed Quote & timeline
Workmanship you can rely on. We'll provide a fixed quote and timeline that gives you peace of mind every step of the way.
Why do a loft conversion
Big Space, Smart Spend, Zero Moving
More Room With Out Moving
Turn unused roof space into a master suite, office or two kids’ rooms—no chain, no stamp duty, no stress.
Adds Real Value
A well-designed loft can lift resale value and buyer appeal—often its one of the best £-for-£ upgrades you can make.
Fast and Low Disruption
Built from the roof down with a tidy-site policy. Most projects complete in weeks, not months.
Guaranteed Workmanship
Manufacturer warranties plus our own guarantee for real peace of mind.
Why do a loft conversion
Big Space, Smart Spend, Zero Moving
Mansard
The biggest loft conversion you can add to a property, it gives the most space and ultimately adds the most value. The key difference is that the slop of the roof is changed to be near vertical, giving the most usable floor space of any loft conversion.
Dormer
A comfortable middle ground, dormer conversions are easy to install and add a lot of additional floor space as well as fantastic windows bringing in a lot of light to your loft rooms. They are straight forward and quick to install making them an easy choice in most circumstances.
Velux
The quick and easy way to turn your loft in a light liveable space. This type of conversion does not change the roof line so requires very little exterior work, making it the fastest and cheapest option for a conversion. If you do a Velux on one side of your roof you can still have a Dormer or a Mansard on the other.
How we work
Design & build, made simple
At Construct Group Alpha, we design, plan, and build loft conversions across South London. We take care of things end-to-end. One team, one timeline, one clear price.
Reliable team of skilled staff
End to end support
Clear pricing and timelines
Got Questions?
Frequently asked questions
If you have questions about our work or how we can help you, get in touch.
Do you do fixed price work?
Yes, we'll give you a fixed price and timeline based on the scope of your project.
Do I need planning permission?
This depends a lot on what you're looking to achieve and how you own your home. You can do a lot of loft conversions under permitted development. Get in touch and we'll determine what you need to complete your project.
Will a loft conversion add value?
On average loft conversions add 20% to a properties value. This changes a lot based on area, existing property size and similar factors but it is a safe bet that it will add value to your property.
Velux (Roof light conversion)
The Quick, Cost-Smart Upgrade
Velux (rooflight) conversions keep your existing roof shape and add roof windows for natural light and ventilation. Minimal structural work, minimal disruption — the quickest way to turn your loft into usable space.
Best for: Home office, nursery, Guestroom
Planning: Often Permitted Development (No planning needed), but we'll advise.
Build time: Typcially 4 - 6 weeks
Value: Most cost effective loft conversion
Dormer
Serious Space, Sensible Spend
A dormer projects out from the roof, giving you full-height ceilings where you need them. Great for a master bedroom with storage or an ensuite. Clean exterior look, big interior gain.
Best for: Master suite, kids’ bedrooms + storage
Planning: Often Permitted Development (size/placement dependent)
Build time: Typically 6–10 weeks
Value: Excellent space-to-cost balance
Mansard
Maximum Room, Maximum Value
Mansards alter the rear roof slope to a near-vertical face, creating a full-width room with the feel of a natural extra storey. The go-to for period terraces when you want the most space and design flexibility.
Best for: Large master suite, two bedrooms + ensuite, studio
Planning: Planning Permission often required (we handle it)
Build time: Typically 8–12+ weeks
Value: Highest space gain and long-term resale uplift
How It works
Hello to Handover. Easy as 1, 2, 3
1
Plan and Quote
We start on site to understand how you live and what you want to change. We measure, check services and structure, and talk finishes so the budget’s real—not guesswork.
Discuss scope and options
Provide Itemised quote
Drawings and specifications
2
Build
Your programme is locked in before we start. A dedicated PM keeps trades moving and updates you by WhatsApp/email so you always know what’s happening.
Site care throughout the whole project
Quality & compliance
Change Control taken care of
3
Handover
We finish cleanly and make sure everything works exactly as agreed. Then we stand by it. Snag free finish, with all certificates provided.
Snag free finish
Documents and certifications
Aftercare
Where we work
Design and Build For South London
We’re based in South London and focus our teams locally so we can start faster and keep sites well managed.
We cover:
Clapham
Brixton
Twickenham
Sutton
Richmond
Lambeth
Southwark
Croydon
Lewisham
Greenwich
And many more - if you don't see your area just get in touch.
MEET THE FOUNDER & CEO
Work We've Done
Balcony. Saville Road
Renovation of Victorian property on SW2 5UY on the brixton clapham boarder. Turning a subprime rental property into a stunning home, blending old and new beautifully. ...more
Portfolio
October 15, 2025•0 min read
Bathroom and pre-market touch up. Solon Road. Sergio & Lynseydsey
Renovation of Victorian property on SW2 5UY on the brixton clapham boarder. Improving a beautiful family home so that it was ready for the market. ...more
Portfolio
September 20, 2025•0 min read
Victoria Flat Renovation Clapham
Renovation of a ground floor Victorian flat in Clapham ...more
Portfolio
September 20, 2025•0 min read
Complete Flat Renovation. SW2 5UY. Richard
Renovation of Victorian property on SW2 5UY on the brixton clapham boarder. Turning a subprime rental property into a stunning home, blending old and new beautifully. ...more
Portfolio
September 20, 2025•2 min read
Balcony. Saville Road
Renovation of Victorian property on SW2 5UY on the brixton clapham boarder. Turning a subprime rental property into a stunning home, blending old and new beautifully. ...more
Portfolio
October 15, 2025•0 min read
Get a quote for your project
Obligation free initial consultation to see how we can support your project.
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