Frequent question: What is the best roof insulation UK?

What is the most effective roof insulation?

Spray foam insulation

One of the most common and effective ways to insulate your roof is with polyurethane spray foam.

Which type of loft insulation is best?

What materials should I use for my loft insulation?

  • Pros of mineral wool: Has excellent thermal and acoustic insulation, is easy to install and offers great fire resistance.
  • Cons of mineral wool: Mineral wool will compress if you put weight on it and can irritate bare skin.

What is the best insulation for rafters?

Mineral wool offers the best all-round thermal, fire and acoustic performance when compared to rigid foam boards to insulate between rafters. Mineral wool friction fits between rafters, providing an optimum seal and preventing gaps associated with rigid foam boards, which can otherwise lead to unwanted heat loss.

How thick should loft insulation be UK?

The recommended depth for loft insulation is 270 millimetres for glass wool, 250 millimetres for rock wool or 220 millimetres for cellulose.

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How do I choose roof insulation?

R value is a measure of the insulation’s ability to resist heat flow. The higher the R value, the better the resistance. Insulation with a lower R value tends to cost less, but lower R values aren’t suitable for all climates and circumstances. The best ceiling insulation should have an R value between 3.5 and 5.0.

Should I insulate the underside of my roof?

Air flow helps to stave off the formation of various wood eating molds and mildews. Just packing R-30 insulation against the underside of your roof deck will insulate it but do nothing to dissipate the inevitable moisture that will be trapped within the insulation.

Should I remove old loft insulation?

If it’s fibre glass or rock wool, for example, there is a risk that you could breathe in the fibres. If the fibres are the reason that you want to remove it (to prevent any inhalation whilst you’re in the loft) then it’s really a job best left for the professionals.

Can you put too much insulation in attic?

It is possible to over-insulate your house so much that it can’t breathe. The whole point of home insulation is to tightly seal your home’s interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That’s when mold starts to grow.

Can you put new insulation over old?

According to ENERGY STAR®, you can put new insulation over old insulation, “unless it is wet. … The vapor retarder on top of or between layers of insulation can trap moisture. Any existing batt or roll insulation in the attic should have the facing against the attic drywall floor or no facing at all.

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Should I insulate between rafters?

The general advice we give is that you should always insulate between and above the rafters (warm roof) or between and under the rafters (cold roof).

How thick should rafter insulation be?

Make sure the insulation is 50mm below the actual roof, which can be done using the battens as your measuring gauge for the breathable area between the roof and the insulating material. Depending how deep your rafter is you may be able to fit two layers of 100mm thick wool insulation.

Can you put too much insulation in loft?

As long as you ventilate your property properly, you can have as much insulation as you like within reason. The trick with loft insulation is to balance the amount of insulation you have with the amount of ventilation necessary to prevent damp. As long as you get that balance right, you should be fine.

How much does it cost to insulate a loft?

A minimum R-value of 6.1 is recommended for loft floor insulation, but ideally it would be up to 7.0. Use the table below to work out how the depth of your existing loft insulation translates into an R-value. This is just for glass mineral wool insulation – the most common and popular material.

The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.

Roofs and roofing