Monday, the excavation/foundation company, Palo Alto Concrete came out to stake and string the where things would be so that that they could know where to dig. Pink strings, Orange strings, wood stakes, pink and orange ground marking paint, all the tools of the trade. I haven't figured out the color coding yet…
|Palo Alto Concrete staking
|Stakes, string, colors… tell them where things are.
There was one other identifier that I noticed when I walked the site at the end of the day:
|Oops, have to be careful of shadows.
What is a stitch pier, you ask?
Well, since we are building a very big basement (1500 sq. feet and 10 foot 2 inch ceilings) and a very thin lot. During excavation, there is a lot of dirt that is going to be removed and the hole is going to be very close to the edges of the property. So that the houses next to us don't slide into the hole, we have to spend some considerable effort shoring up along the property lines. That is where the stitch piers come in…
Every 3 feet along the property, where the cut was within a certain amount of the property line, a very deep hole is drilled and then filled with rebar and concrete. Those are the stitch piers.
It all started around 10:30 as I watched from home:
|Attaching the auger
In all, 24 holes were drilled. Their final depth? 22 feet. Final width? About 14" but I did not get close enough to actually measure the diameter.
The guys who run the operation are amazing. They did one run of the holes with the regular bit. Started on one side, finished on the other side. Then they attached the extension to the bit and that allowed them to get 22' deep. They started on the last hole they dug and then did the order in reverse (VERY efficient). They were in some places about 6-8 inches from the fence and they did not even nick the fence. They had to drill right next to a cedar tree and they hardly upset a branch. It was amazing.
Here is the progression.
|Drilling the initial hole. Did not even nick the fence.
|My favorite part: cleaning the auger.
|Sample finished hole.
|Adding the extension to the bit.
|Filling the hole with concrete.
|The finished pier. Rebar embedded, concrete poured.
|Juan, the master pier maker!
Some random thoughts from the day:
- Memories of playing with Tonka trucks came flooding back and it was cool… but I have to say, life-size trucks are so much fun to watch too.
- Machetes are scary powerful. While they were drilling, some of our old landscaping edging got in the way. In one swoop, 3" solid plastic edging was cut away. Advice: if someone comes at you with a machete, run fast. There is no such thing as a nick from those things.
- Not sure why folks who work in construction are sometimes called "unskilled workers". Even the guy just shoveling is skilled in making the process work efficiently and effectively. And the machine operators? Those guys have mad skills.
- The sound of concrete, falling 22' to the bottom of a hole is a pretty impressive rumble.
I have videos from the day once they are on YouTube, I will link to them.
Today they finish the last of the piers and then they start digging the basement. Yoohoo!