Insulated garden rooms
Insulated Garden Rooms, Priced as a Choice
Every LouMil garden room can be insulated and plastered. We just don't hide it in the headline price. Select the insulation & plastering package and your prefabricated room is lined with 100mm insulation, foil-wrapped under the floor and plastered inside — ready to heat and use in January.
Garden rooms from £9,000 inc. VAT. The package is priced per square metre and shown before you commit.
4m x 3m Composite Garden Room – Stafford — insulated, plastered and wired
What the package includes
Insulation & plastering, item by item
100mm insulation in the walls and ceiling
Fitted between the studs and joists of the prefabricated panels before the room is lined.
Foil-wrapped floor
A reflective foil layer under the floor deck to reduce heat loss into the base.
Plastered internal finish
Boarded and skimmed ready for decorating. Painting is a separate option, or many customers do it themselves.
Pairs with the electrical package
Insulation keeps the heat in; the electrical package with its wall-mounted heater puts the heat there in the first place.
At 16ft × 13ft the insulation & plastering package adds £2,691 and the electrical package adds £1,740. Calculated live from current pricing.
What it adds to the price
Base price vs insulated price at real sizes
Because the package is priced per square metre, the uplift grows with the room. These figures include VAT, delivery and installation and are generated by the calculator's pricing engine.
| Size | Base specification | With insulation & plastering |
|---|---|---|
| 12ft × 10ft11.1 m² | £8,764 | £10,643 |
| 16ft × 13ft19.3 m² | £10,121 | £12,812 |
| 20ft × 13ft24.2 m² | £10,976 | £14,140 |
| 26ft × 13ft31.4 m² | £12,156 | £16,028 |
Do you need it?
When insulation is worth selecting — and when it isn't
You will use it in winter
An uninsulated timber building follows the outside temperature. If the room is an office, gym or studio you use every week, insulation is the difference between using it and avoiding it from November to March.
You want a plastered, room-like interior
The plastered finish is part of the package. If you want the inside to look like a room in your house rather than a shed, this is the option that delivers it.
You are heating it
Heating an uninsulated room is expensive and slow. With insulation, the wall-mounted heater in the electrical package brings a typical room up to temperature quickly and holds it.
You might not need it
A summer studio, a covered bar for warm evenings or a store for garden furniture may be perfectly happy as the base specification. That is why we sell insulation as a choice rather than build it into every price.
Insulated and finished
Insulated garden rooms we have installed
Rooms where the customer selected insulation & plastering, photographed after handover.
Insulation questions
Insulated garden room FAQs
Are LouMil garden rooms insulated as standard?
No — insulation & plastering is a selectable package. The base specification is a weather-tight prefabricated building with cladding, an EPDM roof, French doors and two full-height windows. Choosing the package adds 100mm insulation to the walls and ceiling, a foil-wrapped floor and a plastered internal finish.
How much does an insulated garden room cost?
The insulation & plastering package is priced per square metre, so the uplift depends on the size of your room. The table on this page shows the base and insulated price side by side for four common sizes, calculated live from our current pricing. The calculator gives the exact figure for your size.
Can I use an insulated garden room all year round?
Yes, provided it is heated. Insulation slows heat loss; it does not create heat. Most customers pair the insulation & plastering package with the electrical package, which includes a wall-mounted heater, lighting and sockets.
Does the insulated package include flooring and decorating?
No. Laminate flooring is a separate option and decorating is a separate, deliberately premium option carried out once the plaster has dried. Many customers choose to paint the room themselves.
Does insulation affect planning permission?
Insulation itself does not change the planning position. Many garden rooms fall under permitted development, but the rules depend on height, position, use and whether your property is listed or in a conservation area. We advise on your specific situation before you commit and, where an application is needed, we tell you before you order.
What guarantee applies?
The structure and EPDM roof carry our 10-year guarantee. Doors, windows, electrical fittings and other components are covered by their manufacturers' warranties.
Useful next steps
Where to go from here
See your price
Choose your size and specification in the calculator and see the full price including VAT.
Read moreGarden room prices
What the base price includes, what the options cost and worked examples at real sizes.
Read moreBest insulation for garden rooms
How insulation works in a timber garden room and what to look for.
Read moreYear-round garden rooms
What you need for a room that works twelve months a year.
Read more