The next stage, in order to pour our first countertop, was prepping the dry ingredients the night before. We wanted to have as much time as possible the next day to devote to the time-sensitive process of making the concrete countertops. We had six slabs total to make: a small corner piece to the right of the stove, a large slab that needed to accommodate the sink, one for the window area, and one for the island (with two more for the waterfall sides). Spencer and I created the smallest countertop first – as more of a “if we mess this up, at least it’s not a huge amount of material wasted”.
Again, there were dry and wet ingredients… but we could measure & prep the dry ingredients beforehand.
What does each of these ingredients do?
– The sand is a typical ingredient of concrete, “sieve 30” refers to the granule size.
– Alto-pozz: a few great characteristics are that it improves strength & density and also reduces shrinkage when drying & concrete permeability.
– Black Iron Oxide adds color.
– Portland Cement is a typical ingredient of concrete.
– PVA Fibers help strengthen the concrete & “disappear” in the visible surface layer.
– Glass Fibers help strengthen & add tensile reinforcement to the concrete.
Countertop dry mixing tools:
– thick “cleaning” gloves, respirator, goggles
– 20.9 gal. large concrete mixing tub (x2)
– 10 gal. small concrete mixing tub (x2)
– various small buckets
– colander, trowel, hoe
First, we needed sieve 30 sand… this is a certain grain size. Unfortunately, no one knew what we were talking about when we asked around at supply stores. So, we decided to do something in order to get reasonably close: we sifted a regular bag of all-purpose sand with an inexpensive colander.
We next measured out the alto-poz and black iron oxide.
Weighing the black iron oxide:
Mixing the sand, alto-pozz, and black iron oxide.
(We needed to use multiple tubs because the mix wouldn’t fit in just one):
The first three ingredients mixed and ready!
Because they were also dry ingredients, we took the opportunity to measure out both amounts of PVA fibers and Glass fibers… and also the Portland Cement (even though we would be adding them later with the wet ingredients).
- thick "cleaning" gloves, respirator, goggles
- 20.9 gal. large concrete mixing tub (x2)
- 10 gal. small concrete mixing tub (x2)
- various small buckets
- colander, trowel, hoe
- sieve 30 sand
- Portland cement
- Black Iron Oxide
- PVA Fibers / Glass Fibers
I highly recommend doing these measurements before the day of the pour. Being careful and making sure the components are measured accurately is important and, because this step took a few hours, it was nice to be able to get started the next day knowing this part of the job was already done.
Next up, a pretty long blog post about actually making our concrete countertops!
Here’s a list of all of our concrete countertop posts:
Part 1) Materials and tools needed
Part 2) Making the templates & forms
Part 3) Preparation for the pour
Part 4) The first stage: spraying the beauty coat
Part 5) The second stage: compacting
Part 6) finishing: grinding, sanding, coating
Part 7) installation day
Part 8) the reveal