We’re going to build a new house, out of giant polystyrene lego blocks. It will have an early-1500s medieval manor vibe.
Several people at my work have built houses in this way. Most people just render the polystyrene, and some put stone veneer on it. That’s what we’ll do, as it helps with the medieval look.
You can buy the stone veneer commercially. As a cost-saving measure, we’ve decided to make our own.
We’ve imported some rubber moulds from the US and we have started casting our own stones from concrete. We’re still at the stage of experimenting with colours. We have 14 standard moulds; each makes 3-4 rocks about an inch thick. We need to do this every day for a long time.
Some of the moulds produce stones to go around corners – they take a little more effort, and the results are good. We have 4 of the corner moulds; in theory we only need 2 for the right proportion, but got extras so that we shouldn’t notice duplicates.
The concrete gets a base colour, and then we paint them with some “face dye” (cement + colouring oxides). That gives it a more natural variation, and we’re still experimenting with application techniques.
Our friend Mog has lent us a concrete mixer, to help us work out what size mixer we need. His is not really big enough, so we’ve ordered a bigger one on-line (cheap, so we hope it lasts). Each mix uses a bag of cement, two big buckets of aggregate, colouring oxides, and various additives. The good news is that two mixes fill all our moulds quite neatly.
The moulds are quite heavy, and there’s much lugging of packets of cement and buckets of concrete. We’re getting a regular workout, and for about the cost of gym memberships we’ll get the rock for our house.