Garden Room Insulation – How well insulated is a Green Retreat?

What are our garden room insulation values?

insulated year round garden room infographic

When researching your new garden room project, one of the main areas of concern for customers is how warm the building will during the coldest winter months. Our insulated garden rooms are a world away from damp sheds and log cabins, and we work hard to ensure that our garden room insulation values (also referred to as u-values) are engineered to the highest standard. This is to ensure that you can use your space all year round; as a garden gym, office or relaxation space – really, for almost anything you like!

winter insulated garden room

Truth be told, a garden room from Green Retreats is a lot more like a room inside your house. Our construction techniques mirror those of Scandinavian house builders, a tried and tested construction model in climates far harsher than ours.

About our garden room insulation materials:


Floor & Roof

We use structurally insulated 60mm roof panels and 80mm floor panels in our garden buildings. These panels provide decades of life expectancy, outlasting EPDM rubber and felt roofs that are often used by our competitors. Our floor and roof panels also add to our unrivalled levels of insulation for a garden room, which slot and bolt together quickly, meaning we are on site for less time and you can start moving into your new space.


Our walls are designed to be both thermally and space efficient to ensures the best u-values and maximum internal space. Our wall thickness is 100mm, which includes 45mm of Rockwool insulation and a scientifically developed thermal vapour barrier called Photonwrap. This allows moisture to escape and it also reflects heat back into your garden room in the winter months.


Double glazing like you’d find in a residential house in our doors and windows complete the puzzle. We have partnered with Clear Edge uPVC, who are based on the same business park as our Buckinghamshire showroom and factory. Clear Edge and Green Retreats have worked tirelessly to manufacture doors and windows using state-of-the-art machinery and uPVC materials. This partnership allows us to create market-leading double glazing units for our garden rooms, offices and studios.

Heating Included!

An wall-mounted radiator (is supplied to you as standard, already included in the price of every building. Due to our superior wall cavity insulation, this oil-filled radiator is more than sufficient to heat your garden room in the winter. Effective engineering of our materials means that our buildings are efficient without having to meet costly building regulation standards.

We also offer optional upgrades of underfloor heating and even air-conditioning for complete temperature control.

U-Values – The Science of our Garden Room Insulation

The u-values of our garden rooms can be found below. Our manufacturing page contains even more information about our construction methods:

  • Glazing: U-Value 1.2
  • Walls: U-Value 0.31
  • Roof: U-Value 0.35
  • Floor: U-Value 0.23

The lower the u-value the better a material is at reducing thermal transfer, so keeping the heat in and the cold out! We have these measurements for our individual materials to give you an idea of just how efficient our buildings are! Each building is custom made to your specification (size, number of windows etc) so the total u-value of each building will differ. However, because we use premium materials to keep our buildings insultated you won’t need to worry about feeling the outside elements.

Interested in designing your year-round garden room? Get in touch today!

If you would like to talk to us about your garden room project, why not book a free site survey & design consultation with one of our friendly and knowledgeable on-site consultants?

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Building Measurements

You can get a great idea of how your new garden office will look by using the 360 degree rotating viewer.

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Design Your Building

Start designing your garden room today using our online Visualiser tool. You’ll be able to choose your style, size, finishes and get an accurate cost.

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