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Is Mineral Wool and Multifoil a good combination for Insulation?


As far as interior spaces are concerned, the ideal is to have a place that is warm in winter and cool in summer. This does not only save money in terms of heating and cooling expenses, but it also adds to the comfort levels inside a home. When it comes to temperature control during the different seasons, there are certain things that work incredibly well. The combination of Mineral Wool and Multifoil is one of them. Let’s take a look at this combination and whey it is such an effective insulation solution 


Multifoil is one of the best ways to insulate roofs, walls, and floors. Our standard SF19+ has a high Thermal R-Value of 2.49 (in a roof). Generally speaking, 40mm thick multifoil has the same insulating performance as 120mm thick fibre insulation. This is because they reflect heat back into a building as well as prevent heat from entering a building.   

Installation of multifoil is incredibly easy and it is also relatively affordable when compared to conventional insulation methods.   

Mineral Wool 

Also called rock wool, mineral wool is a dense and high-quality material that is used for insulation, similar to fibreglass. It is easier to handle than fiberglass, and you can easily cut it to fit your wall or roof spacings. It will also keep its form over time, so you don’t have to fasten it to the side planks or the back of the wall. Mineral wool is, therefore, a much better insulation option than fibreglass, but it is more expensive.  


One of the most effective insulation options is to use mineral wool in combination with multifoil. 120mm of mineral wool on its own may give a U-value of around 0.24. When you add a layer of multifoil such as SF19+, this U value improves to around 0.18 helping you to achieve typical retrofit building regs easily. This solution also has many additional benefits that aren’t achieved by using a traditional approach, for example by adding the multifoil you will also significantly improve air tightness. Draughts in your home can make the room much less comfortable and the “wind chill” factor typically requires up to 3 degrees higher room temperature to combat. Compared to foam board solutions there are also significant cost savings in terms of both materials & labour with a mineral wool & SF19+ solution coming in at around £10 per sqm vs 125mm PIR at around £20 per sqm.


Multifoil Insulation has many great benefits over traditional insulation, their radiant barrier properties can reduce solar heat gain during the hot summer months and keep the interior heat inside during winter. They can also be used to minimise the effects of cold bridging by timbers and offer an airtight solution to help reduce draughts. Mineral wool is a very cost effective way to insulate provided you have enough space and has many additional benefits such as its acoustic performance helping to reduce noise pollution.

Both mineral wool and multifoil are great insulations in their own right. By using them together in a “combi” system you can take advantage of both insulations best qualities to improve overall efficiency at a reduced cost making sure you get great value for money and can rest assured your home is insulated to the highest standard.

There are numerous options available for effective insulation whether your working on a new build, extension or loft conversion so when your working on your next project give this solution a shot and you may just be surprised at how effective it really is.