We have recently decided to venture into casting concrete numbers and letters after being asked to make some 3D letters for a customer in a concrete finish. At the time we ended up making the letters in a different material and painted them up to look like concrete. They were used on a shop sign fixed onto a masonry painted rendered wall. Concrete letters were too heavy for using shop sign as they were 400mm high and 50mm thick.
After some research we came up with a solution for the production of concrete letters and numbers in a selection of fonts and heights.
At the moment we have made numbers 150mm high, 50mm thick, we should be able to cast characters at 100mm high in a couple of fonts and cast larger characters up to 300mm high at 25mm thick. The stroke thickness of the characters must not be less than 25mm.
The characters may be reinforced with metal rods for extra strength and the concrete will have extra binders to increase frost resistance and increase strength.
The numbers are supplied with brass fixings on the back for fitting onto walls or they could be supplied without any fixings for cementing direct onto stone or brick walls.
The letters should last for many many years.