25 kg bag of cement

CO2e: 25kg (16 days 15 hours)

Mark Brinkley gives the price of a 25kg bag of cement as £2.77 in September 2005.
(http://www.housebuildersupdate.co.uk/2005/09/building-materials-price-update.html)

1kg  cement causes about 1 kg CO2e so if carbon taxes applied the following prices would hold

CO2 tax in £/t Bag of cement in £
0 2.77
10 3.02
40 3.77
100 5.02

Bulding Construction (York College)

45,000 tonnes CO2e (8000 years)

This is the new building for York Colleges. It is approximately 29,500 sq meters.
Assuming 650 kgs of CO2e per square meter (similar to BEDZED ?) gives 19,175 tonnes of CO2e

Part of the funding for the new college depends on planning permission for 350 new houses.
No doubt these will be ocnventional build c 65 tonnes CO2e per dwelling, giving 22750 tonnes CO2e.

Add 10% for surrounding works, gives an estimate of 45,000 tonnes of CO2e

Using environmentally friendly building materials, such as Hempcrete, could have made the construction of this new college and housing carbon negative.

Three Bedroom Flat

CO2e: 65 tonnes (433 days)

“Construction Materials Report for the Beddington Zero (Fossil) Energy Development” from BioRegional, http://www.bioregional.com, discusses embodied CO2 in BEDZED

This gives the embodied CO2 for BEDZED as 650 Kgs CO2 per square metre.  That’s 65 tonnes of CO2 for a 100 m2 flat.