[tadd]

Originally Posted by jyl

Looks like the printing is of the foundation forms and then part of the wall structure. Everything else - including roof and floors - is built conventionally. That determines the maximum amount of time and money this process can save. If foundation and walls are 20% of total “hard” house construction cost, and printing is 80% cheaper than conventional methods, then hard cost can be reduced by 16% (just a made-up example).

The reduction in total house cost may be much less than that, because printing doesn’t affect the “soft” costs (financing, permitting, selling, overhead) or the land cost. For the typical single family house in the US, soft and land costs can be comparable to hard costs. In other situations, that may not be so.

Concrete is not exactly an environmentally benign construction material. From an environmental standpoint, it may be better to use wood - renewable resource, sequesters carbon.

The ability to create curved and complex shapes is cool, but maybe of limited use for most housing.

Also, I am unclear on whether the void between the inner and outer walls has to be filled with rebar and poured cement, or if you can print an internal structure to the wall.

The CO2 expensive bit is making the quick lime. That could be captured. But what is interesting is that fresh concrete will reaborb 40-50% of what it took to create it in jst a few years. Process slows down as the CO2 has to go deeper into the slab or structure. Some design studies using a patterned or porous concrete suggest almost 90% could be readsorbed.