Most people start with the same question. Do I need an insulated garden room, or will a summer house do the job?
Both are timber buildings. Both sit at the bottom of the garden. From the outside, they can look very similar. The difference is what happens inside the walls, and that changes how you can use the building through the year.
Here is a simple guide to help you choose.
What is an insulated garden room?
An insulated garden room is built to be used all year. The walls, roof and floor are packed with insulation, then lined on the inside so the space feels like a room in your house rather than a shed.
At Poultons, this is the build we use for garden offices and studios. The walls hold 100mm Earthwool insulation, the roof is insulated in the same way, and the floor has polystyrene under 18mm interlocking chipboard. Inside, the walls are lined with 16mm tongue and groove boarding. Doors and windows are double glazed.
The result is a wall that works about as well as 300mm of solid timber. In plain terms, it holds heat in during winter and keeps the worst of the summer heat out.
What is a standard summer house?
A summer house is a single-skin timber building. There is no insulation in the walls and no internal lining, so you are looking at the back of the cladding from inside.
Our summer houses come in named designs such as the Woodham, Pelham, Farnham and Mersea Chalet, plus corner cabins that tuck neatly into an awkward corner. They are lovely spaces for reading, hobbies, garden furniture and long summer evenings.
They are just not built to hold heat. On a cold January morning, a summer house will be roughly the same temperature as your garden.
Side-by-side comparison
| Insulated garden room | Standard summer house | |
|---|---|---|
| Insulation | 100mm Earthwool in walls and roof, insulated floor | None |
| Internal lining | 16mm tongue and groove boarding | None, cladding is visible inside |
| Glazing | Double-glazed doors and windows | Single glazed |
| Comfortable months | All twelve | Roughly April to October |
| Best for | Home office, studio, gym, guest space, therapy room | Relaxing, hobbies, garden bar, storage of soft furniture |
| Heating needed | Light heating only, and it stays warm | Heating escapes quickly |
| Framing | Heavy-duty 38 x 75mm timber | Lighter timber frame |
| Cost | Higher to buy, cheaper to run | Lower to buy, dearer to heat |
| Adds usable space to the home | Yes, works like an extra room | Seasonal extra space |
Build quality is where the money goes
It is hard to judge a timber building from a photograph, so it helps to read the actual specification.
Compare our standard apex shed specification with our heavy duty apex shed specification and the pattern becomes clear.
The standard build uses 38 x 50mm planed framing, 16mm floor boarding and Supershed mineral felt. The heavy-duty build steps up to 38 x 75mm framing, 22mm floor boarding, deeper roof purlins and Glastex SBS felt. Both use 19mm shiplap cladding, so the visible timber is the same. The difference sits in the bones.
An insulated garden room is built on that heavier frame, then insulated and lined on top. That is why it costs more, and why it lasts well under daily use.
Which one suits your plan?
Ask yourself one question. Will you use it in December?
Choose an insulated garden room if you plan to work from it, run a business from it, use it as a gym, put a desk and computer in it, or have guests stay. Anything with power, screens or people sitting still for hours needs warmth.
Choose a summer house if it is a warm-weather space. Somewhere to sit with a coffee, pot up plants, keep the garden furniture dry, or set up a garden bar for the summer.
One more thing worth knowing. People often buy a summer house, love it, then want to use it in winter and find they cannot. Retrofitting insulation later costs more than building it in at the start.
Running costs
An uninsulated building loses heat almost as fast as you make it. Put a heater in a summer house in February, and you are heating the garden.
An insulated garden room holds the warmth, so a small electric heater or panel heater is usually enough. Over a few winters, that difference adds up.
Planning permission
Most garden buildings in England fall under permitted development, which means no planning application is needed. There are limits on height, position and how much of the garden you cover. The official rules for outbuildings are set out on the Planning Portal, and they apply to sheds, summer houses and garden rooms alike.
If your home is a flat, a listed building, or sits in a conservation area or national park, check with your council first.
Not sure which you need?
Send us your postcode and what you want to use the building for. That is all we need to point you in the right direction, tell you what will fit, and give you a realistic price.
We have been building timber garden buildings in Danbury, Essex since 1951, so we would rather steer you to the right building than sell you the wrong one.
Not ready to talk yet? Have a look through the price list brochure and take your time.