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It isn’t difficult to recommend Earthwool roof insulation – it is considered to be the softest and least itchy of all the popular glasswool insulation brand, and is backed by a 50 year warranty. Available in R-Values from R2.5 and all the way through to R6.0, you can be certain that there is an R-Value to suit your home wherever you should happen to live.
A note about Ceiling Insulation and How it Works
If you’ve done some research on ceiling insulation, and find yourself inundated with confusing and even contradictory information, don’t lose heart – the fundamental principles of ceiling or roof insulation, why you need it, and how much you need, are actually very simple and basically amounts to the following:
- Without roof insulation, a huge portion of your indoor heating and cooling is going to waste, escaping through the ceiling
- Installing a layer of ceiling insulation stops this unwanted heat transfer in its tracks
- Most roof insulation types, including Knauf Earthwool – are classed as ‘bulk insulation’
- The secret behind bulk roof insulation’s thermal insulating properties lies in countless tiny airpockets found in the insulation batts.
- A thicker piece of Earth wool insulation will generally have a higher “R-Rating” – which is a measurement of “Resistance” to heat transfer
- How much insulation you need in your ceiling will largely depend on the climate. Very hot or cold climates generally require higher R-Values.
- With it’s huge, exposed surface area, the roof space is by far the most important part of your house to insulate, as it accounts for the most heat gain and loss.
- Whereas the maximum R-Value in walls and underfloors will often be restricted by the depth of the the studs or joists – you can generally install as much roof insulation as you need or like, without special consideration to the thickness of the ceiling insulation.
Single or Double Layer of Roof Insulation
Roof insulation can be installed in one or more layers. While it is by far the most common practice to install roof insulation as a single layer, between the ceiling joists, some home owners choose to go a level up, and add a layer of insulation, perpendicular to the direction of the joists. This approach has both downsides and benefits, so make sure you consider the following before deciding for the two-layer strategy.
There are two main benefits of the double layer
- It effectively seals up any gaps which might have been missed when installing the first layer
- It negates almost entirely the effect of thermal bridging
There are also two main disadvantages with the double layer option
- It takes longer two install (though probably not twice as long)
- It makes it extra tricky to access your roof space, as the supporting joists are not completely hidden from view.
Following are all the available R-Value’s for the Knauf Earthwool Roof Insulation range. We recommend you keep the above points in mind when deciding whether to double up on your ceiling insulation or whether to install a single layer.
- R2.5 Earthwool Thermal Ceiling Batts – 125mm thick
- R3.0 Earthwool Thermal Ceiling Batts – 145mm thick
- R3.5 Earthwool Thermal Ceiling Batts – 175mm thick
- R4.0 Earthwool Thermal Ceiling Batts – 195mm thick
- R5.0 Earthwool Thermal Ceiling Batts – 210mm thick
- R6.0 Earthwool Thermal Ceiling Batts – 275mm thick
Why Are Earthwool Insulation Bags so Heavy?
If you’re used to working with glasswool roof insulation but are installing Earthwool for the first time, you may be excused for thinking that the bag is water-logged. The compact bags can weigh up to 18kg, but this has nothing to do with moisture, but rather with the compression technology used to pack the insulation in the poly bags. One bag of Earthwool roof insulation contains up to twice the square metres of insulation compared to many other common brands, which for the installers means fewer bags to lug into the roof-space!
R2.5, R3.0, R3.5, R4.0, R5.0, R6.0
90% of the m2 ceiling space