Generally un-insulated roofs can be responsible for about If you’re looking to insulate your house as I have been recently you’ll be confronted with quite a wide array of solutions. Personally I’ve been trying to aim for 2010 building regulations so looking to insulate the loft to .016 U. The U value describes how well a building element conducts heat, effectively the lower the U the better it is.

The main types of insulation types I’ve found are PIR Boards, Mineral Wool, Natural Fibres ( sheep’s wool, cellulose) and multifoil. All have their pros and cons with respect to performance, cost and sustainability ratings. I’ve created a brief synopsis for the categories below:


Rigid polyisocyanurate boards are exceptionally thin and achieve very good U values. Oil manufactured so not too hot as a sustainable product. You lay boarding over the backof it once complete and use the actual loft space. Ozone depletion potential (ODP) = 0 , scoring very well here and Global Warming Potential = 3 (GWP), industry standard set at 5 so coming in well below that also. Generally a more expensive option.


Is a non metallic, inorganic product manufactured from glass or rock. The rock wool fibres are created from Volcanic heated and spun rocks to create the fibres, glass fibres are manufactured from glass. The products save more energy in use that is expended in manufacture. However they are also not classed as sustainable products. The end product gets good ratings, ODP = 0 and GWP = 0. Cheaper end of the scale although rockwool will cost more.




Totally environmentally/Human friendly product and usually treated with human friendly products to achieve flame retardancy . One thing should be noted when addressing the product’s sustainable manufacturing potential, in that Sheep (and other grazing animals) account for a large proportion of methane emissions. So if the wool used in the insulation is a by-product of animals going to slaughter then the environmental footprint is minimal, however if the sheep are breed purely for that purpose then things are very different. It has to be said that the vast majority of the wool used here is a by-product of the slaughtered animals so scoring well on the sustainability front and achieving ODP = 0 and GWP = 0. Certainly not the cheapest option in the pack but wholly sustainable.


100% recycled paper insulation product. Largely sourced in the UK, so definitely a highly sustainable product. The material is in a loose state, to install the product you literally tip the contents of the bags out in the loft and spread it out over the rafters very easy to do, its also the cheapest of the bunch. Although you’ll have to make sure no moisture can get into the loft as it will cripple the ability to insulate. Also very good in old buildings with difficult areas to reach or shape rolls or boards.



Multiple layers of foil which are bound together with foam to create air pockets. This material is certainly one of the most efficient on the market and achieves a particularly high U value with minimal depth. Each layer of foil reflects back the heat until the actually heat loss is incredible low. Certainly one of the newest to enter the foray. Again the product generally has good sustainability ratings and as its so thin transport costs are massively reduced, further reducing its carbon footprint. On the cost front this seems to be some place in the middle.

I’m leaning towards sheep’s wool with multifoil coming in second. As you can see there are many options and avenues to pursue.
Does anyone have experience in using these types and what in your opinion do you think is best?
For me personally the conundrum I’m presented with is which really does the best job?
What are the pitfalls of using any particular types do people have any information?