Ultra Grind was contacted to look at a job earlier this year. The client wanted to use concrete as her choice of material as her main reason for this was because the kitchen bench top sat high up in their new penthouse 8 stories high, with the only access was using a lift. That obstacle meant no other suppliers or materials could provide them with a one piece/seamless finish with no joint at all. We took on this job knowing it had never been done before and with our only way we could get 40mpa concrete up to the 8th level was by wheel barrow. The hours of operation that we could work was only during 10:00 am thru to 5:00 pm. this left not many hours to work each day. The bench top measured a whopping 8.8 meters long by 1.55 meters wide and both ends that had a return of 1.1 meters long and returned in 400mm more. The leading edge thickness is 100mm thick, but one of the key points I tried to achieve was to lessen the weight of the overall bench so I filled the base using compressed foam at 50mm thick so this left 50mm of concrete coverage left. One of the other key reasons for doing this was it meant less concrete we had to get upstairs using only the barrows and less chance of allowing the concrete to form a cold join. The formwork took 4 days in total which included the steel work being welded together. The waterfall ends were formed up using steel braces, this bench wasn’t moving at all and we work to very fine tolerances this way. We provided one top mount kitchen sink provision and also a channel underneath that allowed for LED strip lighting.
Pour Day
So far so good, on this day we had 8 guys. 1 working the lift full time. 2 guys below running the wheel barrows from the concrete truck parked out the front 30 meters from the lift itself. Two guys upstairs running the wheel barrows from the lift to the bench top and pouring using buckets then back again. This left the other 3 of us, placing the concrete, vibrating the bench and then screeding it flat. What a mission! After all this we had to wait before we could steel trowel the top with a very tight burnished finish late into the night hitting it several more times all the way until 2:00 am before we were completely happy with the final surface. And tired too! Before we called it a night we formed a hothouse to allow the concrete to dry over the next 7 days before we returned to strip the formwork and polish. Our sealer of choice we used as all ways is Trinics SB1 sealed using 10 coats which took over two days to seal. The owners of the penthouse loved the concrete bench so much and the overall wear and tear they also love. It is the main feature point of their whole apartment and certainly the talking point too! This just goes to show that there really is nothing that can’t be done using concrete without a little pre planning.
