*probably.  

We use 200mm as standard and your house may have as little as 25mm; or maybe nothing at all. If your house has a low energy performance certificate - fill in our 'funding bundle' wizard and we can apply for a reduced cost igloo on your behalf. 

*By volume. PIR is polyisocyanurate, a more ridgid and water resistant type of polyurethane. To reduce costs further in the future we will be making our own PIR because there are only two ingredients; Polyol and Isocyanate. 

The Polyol our supplier use come from recycled polyester; bottles, food packagaing, clothing and shoes cannot be recycled mechanically like other plastics; because they may contain germs these plastics are dissolved in strong solvents, alcohols; and this mixture is called polyol. 

Polyol reacts with Isocyanurate and causes it to expand. We are also experimenting with reducing the embodied carbon in the shell structure; at the moment silicone, kevlar and carbon fibre is never from recycled sources and unfortunately there is not a supply chain in place to recycle it. We have been experimenting with coir; make from cocnuts; your welcome mat is probably made from coir. This will be ready in 2026 after weather testing is complete. PIR is recyclable, but EPS (styrofoam isnt) and we don't use it as it makes up 30% of landfill. 

Here is carbon fibre; very strong in compression. We use rebar in tension much like reinforced concrete. 

We use only the thinnest amount of fibreglass both siica and aramite (kevlar).  This is what we call a win, win, win. Low haulage and storage costs. Low labour costs, and low material cost. 

This means we can forgo steel in compression, think of thick I bars and such. Further we can forgo carbon intensive forms of cladding, such as aluminium. 

All our 32 designs, and any custom builds.  Are inspired by the humble eskimos igloo. It is An igloo naturally ventilates though 'stack effect ventilation' used in passive housing. The small and low opening draws in high density air; any heating element be it an IR heating panel, an IR generating electronic device, or a person will create a density gradient; and the low desnity unclean air ventilates from the opening at the top. 

This is another reason why you shouldn't build a flat roofed garden room. Or have excessively large windows all the way to the ceiling.  It is true that large windows are good for solar gain, but here in the UK the passive house standard prioritises small windows on the north side, rather than the large windows on the south side that the original Spanish passive houses had. 

The primary reason for not building with a flat roof is the surface area to volume ratio; the igloo shape (albeit not so useable at a small scale) is the zenith of passive house design as a low surface area to volume ratio means there is less material, and more resistance against thermal conduction. Our barrel shaped igloos, are built with this in mind too. The lowest possible SA/V is a sphere; sa/v = 1