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Dunster House Ltd.
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Understanding U-Values
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What is a U-Value?

A U-Value is a measure of heat loss found within building materials used for walls, floors and roofs. U-Values are always measured in W/M2K (Watts per Metres2Kelvin). The higher the U-Value of a material is, the worse it performs in relation to retaining heat. So materials with a low U-Value have high levels of insulation.


Why should you insulate?

Good insulation will help protect you from paying large heating bills. For this reason, you should always look at the U-Value of the materials used within the construction of a garden building. As the majority of a building's heat is lost through the roof, walls and floor, insulating these areas is important.


Delivering quality, reliability and value with better insulation

We believe our excellent insulation provides you with a reliable garden building of superior quality at better value for money. Keeping your garden building insulated helps you to control its environment, which protects it from damage. This means you get a garden building which you can use all year round, that is built to last and one that represents a fantastic investment.


All round Insulation: walls

As a rule, timber isn't as good an insulator as materials like polyisocyanurate, which are designed for insulation. For example, a log cabin with a 70mm wall has a U-Value of 1.41. But our best insulated walls, the 145mm TripleTherm™ walls, have a significantly lower U-Value of just 0.28. The reason for this is that we fill the cavity of these walls with 70mm of polyisocyanurate insulation.



u-value graph


This first graph displays the U-Value of timber walls according to thickness. The red bars in the graph display materials used within the construction of our garden buildings. Whereas the blue bars display other materials that we don't use.


All round insulation: roof

Heat rises, so a poorly insulated roof will let out a lot of heat. Although U-Values for roofing are typically higher, the method of measurement is the same. Our roof insulation includes an 10mm MR P5/25mm Polyisocyanurate sandwich panels on top of our 19mm roof boards. This offers excellent roof insulation, compared to standard roof boards, and a U-value of 0.67.



approximate u-value graph


All round insulation: floors

When it comes to insulating a building, the floor is all too often forgotten. Unlike some of our competitors, we don’t forget and offer two different types of underfloor insulation. The first is a 25mm polyisocyanurate sheet suspended below our 19mm or 28mm floor boards, which provides a U-Value of 0.40. Whilst the second is a MR P5/Polyisocyanurate SIPS sandwich panel, which offers a U-Value of 0.77. In comparison the typical 19mm timber floor board has a U-Value of 2.81.


approximate u-value graph


Brickwork comparison graph

Some of you might be thinking "how does the U-Value in the timber used by Dunster House compare to the brickwork of my home?" Well, as you can see our TripleTherm log cabins beat the insulation value of traditional Brick/Cavity/Breezeblock walls used in house construction. In fact, it even has a similar value to the brickwork found within modern house construction, all at a fraction of the cost!


approximate u-value graph


Typical House Construction - 102mm Brick Wall / 50mm Air Cavity / 100mm AAC Blocks / Mineral Wool / 12mm Plasterboard

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