A Plan for York

Different construction methods can be applied to the range of housing types e.g. A detached house with bricks and mortar construction, a concrete framed flat, a wooden park home. MS Copilot compiled a list of 33 housing type/construction method combinations for homes with areas of 90m2.

Brick houses were highest in embodied carbon. Using more timber and less brick cut embodied carbon.

Some construction methods store carbon rather than emit it during construction (e.g. when hempcrete is used). They are often carbon negative when biogenic carbon storage is taken into account. The term biogenic carbon storage is used for the storage of carbon in building materials.

Some argue that biogenic storage should be discounted because, at the end of the dwellings life, the stored carbon is likely to enter the atmosphere e.g. when the dwelling is demolished, and wood & etc will be burnt. This assumes future generations will be as careless of climate change as we have been. If that’s true humanity and the natural world really are doomed.

MS Copilot gave this table for construction methods and embodied carbon for a 3bed 90m2 dwelling.

Construction method.	Gross upfront embodied. kgCO₂e/m²	Biogenic storage. kgCO₂e/m²	Net total for 3 bed (90 m²). tonnes CO2e
Brick and mortar	450–550	~0	40–50
Timber frame + brick façade	300–400	80–150	18–29
Timber + hempcrete	180–260	220–350	−15 to +4
Straw bale + timber	120–200	260–420	−27 to −5
CLT + solid timber	250–350	200–350	−9 to +14

As mentioned above, the world’s remaining carbon budget is critically low. The budget left for 8.3 billion people works out at 16 tonnes CO2 per person. It is irresponsible to emit tens of tonnes of greenhouse gas into the atmosphere to build a house.

The cost of building varies across construction methods and types. The cost of building a timber-framed with brick facade averages about £180,000. The construction cost of a wooden park home averages less than half of this.

Since prefabs and park homes are typically single storey, they may be able to use screw-in foundations reducing cost and carbon footprints.

Many of the construction methods are relatively new. Their costs may decrease in the future.

City of York Council has explicitly required and integrated embodied carbon measurements in its own public housing developments and flagship eco-projects However, City of York Council does not currently make the measurement or reduction of embodied carbon a strict, mandatory requirement at the planning stage for standard private developments.

However, City of York Council can ask for the estimated embodied carbon of a building to accompany planning applications. (Under their climate emergency response and local plan frameworks, the council requires developers to detail the sustainability and whole-life carbon impact of their schemes.)

Sadly, under current planning law in England, City of York Council cannot legally make the estimation of prospective residents’ personal consumption footprints a mandatory condition or validation requirement for planning approval.