So, in this episode I’m going to take a bit of a departure from the usual line that I go down in looking at the different issues, and actually look to the future. There’s so many exciting new developments in construction that are taking place, that really have the power to revolutionise how we build buildings and create buildings that really without that sort of technology, we wouldn’t be able to produce otherwise.

One thing that’s really caught my eye is 3D Printed Construction and its ability to create buildings that you really couldn’t create otherwise from bricks or blocks or timber frame panels – very curved buildings, domes, all sorts of different shapes that really can be quite challenging to produce.

So why would you 3-D print a building? Well, the technology has the power to remove a lot of the vagaries from building sites. Your 3-D printer doesn’t turn up one morning with a bad back or having been down to the pub the night before and be a bit off, and all the crazy things that happen on construction sites across the UK certainly. It will work 24/7. It simply needs to be fed with the right feed stock for printing the building, so the various different materials that it can use, and it produces very precise buildings. There’s virtually no waste with it, other than the small amount of waste that’s left in the pipe between the pump and the printer effectively, and it can produce very strong, very structurally sound, buildings using effectively very small amounts of material.

So the 3-D printing is done by a 3-D printer and that seems to take the form of various guises. Currently there are various different companies producing 3-D printed buildings. Some are actually printing them on site, so some are laying a layer of insulation such as foam glass, that kind of material, an aggregate. Printing a foundation over the top of it, which is then backfilled with concrete and then continuing on to print the ground floor walls, which are printed over the top of the foundations. Coming up to the top of the ground floor walls, a first floor structure is built, potentially pre-fabbed off site and literally just craned on.  And then the second floor can be added through 3-D printing, all the way up to eaves basically. That’s essentially where it finishes.  As far I can tell, currently there aren’t any companies that are printing any roof structures. Those are largely pre-fabbed off site and then craned into position on site to create a weather tight shell.

Some of the other companies are looking at putting down a ground floor slab. So basically a reinforced slab and then just coming straight up off of that. But there’s a whole plethora of different companies doing slight variations on essentially the same theme.

3-D printing is also called ‘additive manufacturing,’ and it basically involves using a computer-controlled print head and when you’re building buildings the print head is obviously quite large, but it’s very similar to how you would ice a cake with a piping bag. It basically has a computer-controlled print head which is fed with a continuous feed of fast setting concrete and the computer moves the print head around and effectively prints a continuous sausage of the cement and slowly that’s built up in layers until you reach whichever height. The walls tend to be made up of an internal and an external skin which are formed by printing these layers and then in between you have a latticework structure, much like a truss beam kind of structure.  And this makes for a very strong structure vertically and horizontally, but of course being made of cement, thermally it’s not really that good. It’s better than solid concrete or concrete block, but it still has significant thermal bridges between the interior skin and the exterior skin.

In addition to that, you are of course using cement concrete, so whilst you’re being much more efficient with how you use it, you are still using something that is relatively polluting. However, in Italy there is a company who are working and doing very well with printing with clay. I think they’re largely targeting the third world in what they’re doing, but they’re sieving soils, local soils, mixing them to a fairly precise consistency and then using a screed pump to pump that through to the print head and force that out through the nozzle in exactly the same way that people are doing with cement.

Obviously because it’s earth, the main difference is speed. You certainly can’t print with earth as quickly as you can with cement because the setting time is as long as it takes to dry as opposed to half an hour or an hour with the fast-settin