Second Storey Extensions in Weymouth, Dorchester, Portland & Wareham: Everything You Need to Know
If your family has outgrown your home but you love where you live, a second storey extension could be the answer. Rather than facing the upheaval, cost and stamp duty of moving house, building upward lets you add valuable space — an extra bedroom, a home office, a family bathroom or a bigger living area — without losing an inch of your garden.
At Dorset Extensions Group, we build second storey extensions across Weymouth, Dorchester, Portland, Wareham and the surrounding Dorset area, helping homeowners get more from their existing property with a build that’s finished to a high standard from start to end.
In this guide, we’ll walk through what a second storey extension involves, how planning and building regulations work in Dorset, and what to expect from the build itself.
What Is a Second Storey Extension?
A second storey extension involves building a new floor above an existing single-storey structure, such as a ground-floor extension, garage, or even part of the original house. It’s a popular choice for homeowners who want to add significant living space without extending the footprint of their property — ideal for homes with a smaller garden or tighter plot in towns like Weymouth or Dorchester.
Common reasons homeowners choose a second storey extension include:
- Adding one or more extra bedrooms as the family grows
- Creating a home office or study
- Adding an additional bathroom or en-suite
- Increasing overall living space and property value
- Making better use of an existing single-storey extension or garage
Do You Need Planning Permission?
In most cases, yes — extending upward typically requires full planning permission from your local authority, unlike some single-storey extensions which may fall under permitted development rights. Requirements can vary depending on your property, its location, and whether it sits within a conservation area, so it’s always worth checking early in the process.
For homeowners in Weymouth, Dorchester, Portland, Wareham and the wider county, planning applications are handled by Dorset Council’s planning department, and general guidance on when permission is required is available via the Planning Portal.
Our team can guide you through the planning process from initial concept to submission, including preparing drawings and liaising with structural engineers where needed. If you’ve already got planning permission in place, we’re happy to review your existing plans and give you a clear idea of build costs.
Will My House Need Underpinning?
One of the biggest myths around second storey extensions is that every project needs underpinning. In reality, many homes can support a new upper floor using their existing footings, once these have been properly assessed. We’ll work with building control to establish whether your current foundations are suitable, or whether some reinforcement is needed.
Even where underpinning is required, it doesn’t automatically mean your project is unaffordable — it’s usually far more manageable than homeowners expect, and we’ll always talk you through the options and costs involved before any work begins.
Scaffolding, Materials & Roofing
Every second storey extension needs scaffolding for the safety of our team and anyone nearby — something we organise as part of the project, so you’re not left juggling multiple contractors.
When it comes to materials, we’ll usually recommend matching your existing property — brick to brick, or block if your home is rendered — to keep the finish consistent and costs sensible. From there, we work from your structural drawings and building regulations to select the right construction method for your extension.
Once the structure is complete, we finish the roof to match your specification, whether that’s a traditional tiled roof or a flat roof finish, so the whole project is handled by one team from foundations to final fix.
Second Storey Extensions Across Weymouth, Dorchester, Portland & Wareham
Every property in Dorset is different, and so is every second storey extension. Whether you’re in a period terrace in Dorchester, a coastal home in Weymouth, a property on Portland, or a house in Wareham with room to grow upward, our team has the local knowledge and building experience to manage your project properly — from planning through to the finishing touches.
We also cover the wider Dorset area, so if you’re just outside these towns, get in touch and we’ll be happy to discuss your project.
Why Choose Dorset Extensions Group?
- Local team covering Weymouth, Dorchester, Portland, Wareham and surrounding Dorset
- Support with planning applications and structural drawings
- Honest advice on underpinning and foundations before you commit to costs
- Scaffolding, materials and roofing all managed as part of the build
- Fully insured, with an insurance-backed warranty on our work
- One dedicated team from first site visit to completion
A second storey extension is a significant investment, and having a builder who manages the whole process — planning, structural work, scaffolding, construction and roofing — makes all the difference to how smoothly the project runs.
If you’re also considering other ways to add space, it’s worth looking at our loft conversions and extensions pages, or browse our photo gallery to see examples of our recent work. Once your new floor is built, our team can also help with fitting a new kitchen or bathroom, or finishing the space with new UPVC windows and doors.
Get a Free Quote for Your Second Storey Extension
If you’re thinking about a second storey extension in Weymouth, Dorchester, Portland, Wareham or anywhere else in Dorset, we’d love to help. Our friendly team offers a no-obligation site visit and quote, so you can find out exactly what’s possible for your home.
Call us today on 01305 310 310
Email info@dorsetextensionsgroup.co.uk Or contact us online to get started
Dorset Extensions Group — Unit 5 Basepoint, 15 Jubilee Close, Weymouth, Dorset DT4 7BS.
Proudly building extensions and garden rooms across Weymouth, Dorchester, Portland, Wareham and the surrounding Dorset area.