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What is a U Value

What is a U Value in its simplest term?

A U Value is a calculation that helps measure how fast heat escapes from your garden building through the roof, floor, windows and how effective your chosen insulator is. When choosing a Log Cabin, the lower the U Value, the better!

Why do we use Polyisocyanurate?

We use Polyisocyanurate as our insulator rather than others available such as rockwool, polystyrene or even bubble wrap. We use Polyisocyanurate because we truly believe it offers the best insulation so your cabin doesn’t lose heat. Due to its effectiveness as an insulator, NASA used it as an insulator for the external fuel tank.

According to Polyisocyanurates.org, Polyisocyanurate foam boards are lightweight but strong, are easy to install and maintain their insulative qualities for as long as your building stands. A 2019 article on Globepanels.com explored the difference between Rockwool and Polyisocyanurate. In the article, they explained that it would take 80mm of Rockwool to match the insulation qualities of just 50mm of Polyisocyanurate.

What is a U Value? Polyisocyanurate Log Cabin Roof Insulation Option

If you’re looking for a Log Cabin, Garden Office or any Garden Building you intend to utilise throughout the year, you need to be looking for this insulator. Any other is simply not going to be as effective.

The benefits of Polyisocyanurate insulation are well known and widely reported, the articles quoted above are just a few of them. Spend some time researching insulators, or call our sales team on 01234 272 445, who will be happy to answer any questions you may have.

*All measurements are approximations.

The Other Option

What is a U Value? Our Warmalog features pre made panels with insulation


If you are looking for a Log Cabin that has a better thermal performance then typical timber, we offer Warmalog cabins. These are insulated Log Cabins which have a 62mm thick sandwich of timber and polyisocyanurate. This reduces your U Value number to just 0.69 W/m2K.

To put this into perspective, our 70mm thick timber walls have a U Value of 1.41 W/m2K. If you wanted to achieve the same results without insulation, you would need to find 140mm thick walls.

If you have fallen in love with another model in our Log Cabin range, then you will benefit to know that our Log Cabins comes with the option to add floor and roof insulation.

Our floor insulation is 25mm thick, dropping the U Value of your cabin from 2.81 W/m2K down to 0.77 W/m2k, saving on heating costs and ensuring you are toasty warm all year round.

Heat rises so naturally you will need a powerful insulator in the roof to retain the heat best you can. Our roof insulation features a sandwich of 10mm MR P5 which is chemically bonded to 25mm Polyisocyanurate. This reduces the U-Value from 3.49 W/m2K down to 0.76 W/m2K*.

Our Log Cabins have various customisation options, including the choice of wall thicknesses (28mm, 45mm and 62mm). Whilst all of our walls offer protection from the elements, the thicker the timber you choose, the lower the U Value and the less heat loss suffered.

We understand that thinking about U Value can be a little confusing, which is why our sales team is standing by ready to answer any questions you may have. Call them us 01234 272 445 or, alternatively, fill in one of the call back forms on our website and they will call you at a convenient time for you.


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