Garden Room Vs. Extension: Which Adds More Value To Your Home?
Everything You Need To Know…
A self-build garden room is an easy, budget friendly, and beautiful way to expand your living space. Whether you’re creating a home office, a home gym, guest room, or a creative studio it’s a great way to reach the full potential of your outdoor space. Our wide range of self-build garden rooms are easy and quick to assemble thanks to our easy installation panel design, and are fully insulated garden rooms, meaning you can use them all year round. Plus, usually you don’t need planning permission so you could have your dream garden room in less than 4 weeks!
Adding electricity to your garden room can give you limitless possibilities for your space, but it’s important to understand what you need and spend some time planning.
The Cost Comparison
A traditional single-storey extension in the UK typically costs anywhere between £30,000 and £80,000, depending on size, location, and specification. In London and the South East, that figure can climb even higher. This is before you factor in architect fees, structural surveys, planning applications, and the inevitable contingency budget for what gets uncovered once the builders are in.
A garden room, by comparison, typically sits between £6,000 and £40,000 for a quality, fully insulated build with electrics included. At Pent Haus, our rooms are designed and built to a specification which means they work as intended all year round, not just in the summer months.
The Hidden Costs Of An Extension
The headline build cost is only part of pricing up an extension. Most homeowners going through an extension project will also need to budget for:
- Planning permission applications (typically £200 to £500, plus the time and uncertainty that comes with waiting for approval)
- Architect or architectural designer fees, which can add 10-15% on top of the build cost
- Temporary accommodation or storage if the work affects a significant part of the home
- Redecoration and finishing once the builders have left, which is rarely included in the original quote.
What’s Included with a Garden Room
A garden room installation is a far more contained process. There are no structural surveys, no party wall agreements, and in most cases no planning permission required at all. The price you are quoted is much closer to the price you pay.
It is also worth noting that a garden room does not eat into your existing living space during the build. Pent Haus installations are completed within a matter of days, with minimal disruption to daily life.
If you have any questions, please take the time to read through our FAQs, designed to answer any queries you may have.
How Long Does Each One Take To Build?
A typical single-storey extension will take anywhere between three and six months from breaking ground to completion. Factor in the time spent finding and appointing an architect, waiting for planning permission, getting quotes from builders, and you are realistically looking at the best part of a year from decision to completion. That is assuming everything runs to schedule!.
The Reality Of Living Through An Extension
It is worth being honest about what that timeline actually looks like from the inside. For several months, your home becomes a building site. If the work is significant enough, some families choose to move out temporarily, which adds cost and disruption on top of everything else.
How Long Does A Garden Room Take?
A Pent Haus garden room follows a very different timeline. Once your order is confirmed and the base is prepared, most installations are completed in 3 days. The structure arrives ready to build, and by the end of the week you have a finished, usable space.
From your initial enquiry to the moment you unlock the door for the first time, the typical Pent Haus journey takes around four to eight weeks. There is no planning permission delay to wait on in most cases, and no sequence of different contractors to coordinate.
Want some inspiration? Check out our garden room ideas!
Planning Permission Questions
For a lot of people, planning permission is the part of any building project that feels the most out of their hands. You submit an application, and then you wait (sometimes for weeks) to find out whether you can proceed. For extensions, that uncertainty is almost always part of the process.
Extensions and Planning Permission
The majority of single-storey extensions require full planning permission, particularly if they extend beyond the rear of the property by more than three metres for a terraced or semi-detached home, or four metres for a detached. Larger projects, side extensions, and anything that affects the roofline will almost certainly need an application regardless of property type.
While the process itself is not complicated, it takes time and carries no guarantees. Local authorities can request amendments, impose conditions, or in some cases refuse permission.
Garden Rooms and Permitted Development
Our garden rooms are designed with permitted development rules built into the process from the start. We have a full guide to planning permission that walks through exactly what applies to your situation, so you are never left guessing.
Which Adds More Value to Your Property?
A well-built extension will almost always add value to a property. Adding a bedroom, a larger kitchen, or a dedicated living space increases the functional footprint of the house in a way that estate agents and buyers understand clearly. For that reason, extensions have traditionally been seen as the safer bet when it comes to return on investment.
However, the picture has shifted.
What the Numbers Say
Property experts generally agree that a well-built, high-quality garden room will significantly contribute to your home’s value. Estimates vary by location and specification, but a well-designed, fully insulated garden room can typically increase property value by between 5% and 15%.
On a £300,000 property, that is a potential uplift of £15,000 to £45,000.
Where The Garden Room Holds Its Own
The key advantage is the ratio of cost to return. A full extension might add more in absolute terms, but at a build cost of £30,000 to £80,000 plus fees, the margin is considerably tighter. A quality garden room delivers a meaningful uplift at a fraction of the outlay.
It is also worth considering how buyers view a finished, usable outbuilding. A dedicated home office, studio, or gym is no longer a novelty. For buyers who are working remotely, it can be a genuine deciding factor.
As we cover in more detail in our guide to garden rooms and property value, the return is not guaranteed and will always depend on build quality and location.
If you want to add a genuinely usable, year-round space without the cost, the disruption, or the planning uncertainty that comes with an extension, a garden room is hard to beat. Faster to build, simpler to approve, and with a return on investment that stacks up well against the alternative.
At Pent Haus, we build garden rooms designed to be used every day, in every season. If you are ready to explore what is possible for your space, please contact us! We would love to help.
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