We have been doing a lot of test pours to figure out how to pour concrete for the lower ceilings in the tiny cottage. The above mold made of 1/2″ pink foam that has a plastic sheet coating is the basic form we use for this test. That part works.
This test was 1/4″ of white concrete which was allowed to cure for a week. Then we poured 1.75″ of grey concrete on top of that. What we should have gotten was a tile that was white on one side and grey on the other. The idea is to use less of the expensive white concrete and then use the grey for the structural element.
Unfortunately the dark color, the iron oxide in the grey concrete, bled down through the white. The resulting tile was quite ugly. Back to the drawing board. Perhaps with a thicker layer of white cement this would have worked.
I may end up just pouring white concrete for the entire thickness of the ceilings. It will be more expensive but fortunately the tiny cottage is small. This is just for the loft, attic and utility room which are the ceilings of the front room, bedroom and bathroom respectively. The miser in me does not want to waste so much good white cement but I really don’t want a ceiling that looks like that.
I’m also toying with various impression techniques such as hay, leaves and various edge moldings.
Outdoors: 76°F/44°F Mostly Sunny
Farm House: 76°F/61°F
Tiny Cottage: 62°F/68°F East Insulation, Pillar Caps