Diary Of An Eco-Builder

Oak bark sounds like the appropriate insulation for tree house, but we need something better

I've been dreaming of insulation for months, but last week we finally fitted the first pieces into Tree House. Grabbing the opportunity of a dry day between the storms, all hands were on deck - the roof deck - to build the thick layer of insulation between the roof's plywood sheathing and the plastic rainscreen that will support our solar power station. By the end of the day the job was done, and the roof was covered in a bright blue tarpaulin just in time for the next downpour.

Our super-insulated roof is not graced with any of the materials alluded to in my dream: hemp, sheep's wool, cork and recycled newspapers. These are all excellent insulants, but - although cork (the bark of the oak Quercus suber) would perhaps be the most fitting choice for Tree House - our roof and floor are in fact being packed with a synthetic product, Kingspan Insulation rigid phenolic boards (www.insulation.kingspan.com).

The key issue with all insulation is to select the most appropriate material for the task. Bark may be all that a tree needs to protect its living tissues from the extremes of the elements, but our "zero carbon" house needs something more substantial. We have chosen rigid phenolic boards for the roof simply because they keep the heat in (or out) better than any other material on the market.

The most important characteristic of any insulant is its thermal conductivity, so always check the value of this when making comparisons. The thermal conductivity of a material is the rate at which heat flows through it when the temperature on one side is greater than the other. This is standardised as the rate of energy flow (in watts) through one metre of material for one degree difference between inside and outside (in degrees Kelvin - the same scale as Centigrade, but starting at absolute zero). Typical values are 0.034 W/mK for mineral wool, 0.037 W/mK for sheep's wool and 0.022 W/mK for phenolic board. The lower the conductivity, the more effective the insulation.

Beyond this bottom line, there are lots of other issues to consider in choosing insulation, such as the size and shape of the space; moisture and fire risks; and the potential for poor installation to undermine effectiveness. For example, we will be spraying Warmcel 500 recycled newspaper (www.excelfibre.com) into our walls because the nooks and crannies of our "I beam" wall studs would not be adequately filled using only rigid boards.

Synthetic insulation materials have often been dismissed by eco-builders because of the blowing agents used in their manufacture. These were originally ozone-depleting CFCs, subsequently replaced by marginally less nasty HCFCs and HFCs. Happily, Kingspan Insulation now produces all its insulants using pentane, which has minimal impact on either the ozone layer or global warming, and any energy used in manufacture is rapidly off-set by its energy-saving performance once installed.

For advice about the insulation in your walls, wall cavities, floors, loft or roof, see the Energy Saving Trust website (www.est.org.uk) or phone 0845 727 7200.

In years to come, our super-insulated roof will keep us cool in hot summers as well as warm in cold winters, so we should sleep soundly beneath it. With any luck, my dreams will be more peaceful too, with all those giggling right-wing sheep long since chased into the wilderness.

Discover more property articles at Homes and Property
Voices
Lucerne’s Hotel Château Gütsch, one of the lots in our Homeless Veterans appeal charity auction
charity appeal
Arts and Entertainment
Tony Hughes (James Nesbitt) after his son Olly disappeared on a family holiday in France
tv
Arts and Entertainment
The Apprentice candidates Roisin Hogan, Solomon Akhtar, Mark Wright, Bianca Miller, Daniel Lassman
tvReview: But which contestants got the boot?
Arts and Entertainment
Jim Carrey and Jeff Daniels ride again in Dumb and Dumber To
filmReview: Dumb And Dumber To was a really stupid idea
PROMOTED VIDEO
News
people

Jo from Northern Ireland was less than impressed by Russell Brand's attempt to stage a publicity stunt

Sport
Scunthorpe goalkeeper Sam Slocombe (left) is congratulated by winning penalty taker Miguel Llera (right)
football
Life and Style
A woman walks by a pandal art installation entitled 'Mars Mission' with the figure of an astronaut during the Durga Puja festival in Calcutta, India
techHow we’ll investigate the existence of, and maybe move in with, our alien neighbours
Arts and Entertainment
Sir Ian McKellen tempts the Cookie Monster
tvSir Ian McKellen joins the Cookie Monster for a lesson on temptation
News
i100
Travel
Tourists bask in the sun beneath the skyscrapers of Dubai
travelBritish embassy uses social media campaign to issue travel advice for festive holiday-makers in UAE
Arts and Entertainment
Jennifer Saunders stars as Miss Windsor, Dennis's hysterical French teacher
filmJennifer Saunders and Kate Moss join David Walliams on set for TV adaptation of The Boy in the Dress
Life and Style
tech
Sport
Nabil Bentaleb (centre) celebrates putting Tottenham ahead
footballTottenham 4 Newcastle 0: Spurs fans dreaming of Wembley final after dominant win
Voices
Jimmy Mubenga died after being restrained on an aircraft by G4S escorts
voicesJonathan Cox: Tragedy of Jimmy Mubenga highlights lack of dignity shown to migrants
Life and Style
Sebastian Siemiatkowski is the 33-year-old co-founder and CEO of Klarna, which provides a simple way for people to buy things online
tech
Property search
Property search
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Ashdown Group: Helpdesk Analyst

£25000 per annum: Ashdown Group: An established media firm based in Surrey is ...

Ashdown Group: Java Developer - Hertfordshire - £47,000 + bonus + benefits

£40000 - £470000 per annum + bonus: Ashdown Group: Java Developer / J2EE Devel...

Ashdown Group: Head of Finance - Financial Director - London - £70,000

£70000 per annum: Ashdown Group: Head of Finance - Financial Controller - Fina...

Recruitment Genius: Business Development Executive - Nationwide - OTE £65,000

£30000 - £65000 per annum: Recruitment Genius: This small technology business ...

Day In a Page

Jeb Bush vs Hillary Clinton: The power dynamics of the two first families

Jeb Bush vs Hillary Clinton

Karen Tumulty explores the power dynamics of the two first families
Stockholm is rivalling Silicon Valley with a hotbed of technology start-ups

Stockholm is rivalling Silicon Valley

The Swedish capital is home to two of the most popular video games in the world, as well as thousands of technology start-ups worth hundreds of millions of pounds – and it's all happened since 2009
Did Japanese workers really get their symbols mixed up and display Santa on a crucifix?

Crucified Santa: Urban myth refuses to die

The story goes that Japanese store workers created a life-size effigy of a smiling "Father Kurisumasu" attached to a facsimile of Our Lord's final instrument of torture
Jennifer Saunders and Kate Moss join David Walliams on set for TV adaptation of The Boy in the Dress

The Boy in the Dress: On set with the stars

Walliams' story about a boy who goes to school in a dress will be shown this Christmas
La Famille Bélier is being touted as this year's Amelie - so why are many in the deaf community outraged by it?

Deaf community outraged by La Famille Bélier

The new film tells the story of a deaf-mute farming family and is being touted as this year's Amelie
10 best high-end laptops

10 best high-end laptops

From lightweight and zippy devices to gaming beasts, we test the latest in top-spec portable computers
Michael Carberry: ‘After such a tough time, I’m not sure I will stay in the game’

Michael Carberry: ‘After such a tough time, I’m not sure I will stay in the game’

The batsman has grown disillusioned after England’s Ashes debacle and allegations linking him to the Pietersen affair
Susie Wolff: A driving force in battle for equality behind the wheel

Susie Wolff: A driving force in battle for equality behind the wheel

The Williams driver has had plenty of doubters, but hopes she will be judged by her ability in the cockpit
Adam Gemili interview: 'No abs Adam' plans to muscle in on Usain Bolt's turf

'No abs Adam' plans to muscle in on Usain Bolt's turf

After a year touched by tragedy, Adam Gemili wants to become the sixth Briton to run a sub-10sec 100m
Calls for a military mental health 'quality mark'

Homeless Veterans campaign

Expert calls for military mental health 'quality mark'
Racton Man: Analysis shows famous skeleton was a 6ft Bronze Age superman

Meet Racton Man

Analysis shows famous skeleton was a 6ft Bronze Age superman
Garden Bridge: St Paul’s adds to £175m project’s troubled waters

Garden Bridge

St Paul’s adds to £175m project’s troubled waters
Stuff your own Christmas mouse ornament: An evening class in taxidermy with a festive feel

Stuff your own Christmas mouse ornament

An evening class in taxidermy with a festive feel
Joint Enterprise: The legal doctrine which critics say has caused hundreds of miscarriages of justice

Joint Enterprise

The legal doctrine which critics say has caused hundreds of miscarriages of justice
Freud and Eros: Love, Lust and Longing at the Freud Museum: Objects of Desire

Freud and Eros

Love, Lust and Longing at the Freud Museum