In the Aggregate

The delivered pile of crushed ashfield stone.

The floor for the dining hall is a very large cement slab. It will have the benefit of radiant heat and will be very durable - and important feature which will last through the many muddy boots of young farmers that are expected to tread over its surface. However, in chosing a concrete floor we also wanted to ensure that it had an asthetic appeal matched the majestic timberframe overhead and that made it more than just a giant gray monolith.

raw material from the Ashfield Stone quarry

After much research and discussion, we made the decision that grinding the surface of the floor was the way to go. This is a process that uses diamond abrasives to grind off the top surface of the cement floor after it has hardened. This grinding reveals the stone that is part of the concrete mix - commonly referred to as the aggregate. The result is polished, glassy-smooth floor that is surprisingly not slippery, and one that has an interesting pattern of stone revealed - similar to terrazzo floor. The effect is a beautiful, interesting floor that is also incredibly hard and resistant to scratching, stains or other kinds of wear.

To customize this floor and get a color that is appealing, one can dye the concrete to different shades, but more importantly, choose an aggregate matches color and shapes that you want. This aggregate is hand-cast over the cement after the floor has been poured, and then troweled smooth - leaving the chosen aggregate near the top and ready to be revealed.

In our case, we chose ashfield stone for its cool gray color as well as the local connection of Ashfield Stone which is located just a couple miles up the road and whom we consider a neighbor of Apple Valley. By this time, we were anxious to get a supply (about half a ton) in time for the concrete pour which was happening soon. Thus launched an interesting process to get the stone we needed.

The size of the stone was the first consideration. We wanted what is called “half-inch-minus” which refers to crushed stone that is…. you guessed it, half an inch or smaller. Ashfield Stone does not carry a crushed version of their quarried stone, but I was able to find Tonlino & Sons in East Otis, Massachusetts where they had a crusher and were willing to do a custom crushing for us. Johanna Anderson-Pratt, owner of Ashfield Stone helped me arrange for the supply of their cut-offs and pieces of stone that we could crush. A few phone calls later to Kyle Canepari to arrange trucking, and we were in business.

The aggregate before washing with all the dust and smaller material

Now we have a pile of crushed ashfield stone that will be perfect for our floor. It needs to be washed, as there is still a tremendous amount of dust and smaller particulate that we don’t want to include. However, that is a relatively simple process. Once washed, you can see the individual pieces with all their beautiful characteristics that are so unique to ashfield stone.

what the washed aggregate looks like

Mike Frost from Vermont Eco Floors will come down for the pouring of the floor by Valley Concrete and hand broadcast this aggregate across the floor along with a small amont of limestone to create some white contrasting. The concrete is being pre-dyed a cooler shade of gray to provide an appropriate color background. Some weeks later, Mike will return with his crew to do the grinding, and our floor will be revealed.

Whew! Lots of coordination, participation, advice and logistics. But in the end I think we will end up with a really special floor that is not only pragmatic, but a gorgeous complement to our new dining hall space.