While I was still trying to get my head around the scope of this project I figured I could get under the house and start digging the holes for my new piers. The engineer spec’d 2’x2’x1′ deep. With the help of my neighbor I dug the first hole and built a form for it. I did the same for the other site. I called the county to come and inspect my forms, which they did and said they were fine and they passed my concrete form inspection.
Later I decided that I didn’t like the fact that I couldn’t remove the entire form after the pour. I also thought that 12 inches deep wasn’t deep enough, so I dug them out another 12 inches.
I put about 4″ of gravel in the bottom of the hole, then put four 8x8x16 concrete blocks around the perimeter of the hole. This brought the depth of the hole back up to 1 foot deep to the top of the concrete blocks. I pounded some rebar into the ground to hold the blocks in place then attached some rebar horizontally and finally built a wire cage so I could attach my 14″ J bolts. The engineer didn’t call for any reinforcement, but since I needed something to attach the J bolts to, I decided to put it in. Also, I happened to have a bunch of rebar sitting around my garage that needed to be used. The J bolts go thru an 8 inch solid concrete block that sits on top of the pier and the jack base plate is attached to the pier with the J bolts. The J bolts are attached to the rebar in the pier and are sitting in 5 inches of concrete. Like many things in this project I’m building above spec for piece of mind.
Once my forms were built I double checked my J bolt placement and began mixing concrete. Rule number one for mixing concrete is to have extra help on hand. Since I didn’t have any help, I went ahead and got started. Each hole took about eight 80 lb. bags of concrete. Once you start mixing you’re not stopping until you’re done with the pour. I mixed the concrete a bag at a time in a large tub then shoveled it into the forms, making sure that it was settling in properly. About half way through the second one, I realized that I forgot to take pictures. D’oh. Sorry, no pictures of the new holes or forms. Suffice it to say they were glorious. Just kidding they were stupid holes in my crawlspace. Once I was to the top of the form, checked the J bolts then screeded and finally troweled a relatively smooth coat. Finally, I covered them with plastic and cured them for 3 weeks before removing the forms. After the concrete had cured, I put on my 1’x1’x8″ solid concrete block through which I had drilled 4 holes for the J bolts. The solid block let me use a shorter (higher capacity) jack. After the blocks were installed over the J bolts, I wrapped the new piers with some extra plastic that the radon remediation contractor and taped them up. They are now underneath my vapor barrier and everything is sealed back up and working as designed.
Here are the pictures of the piers after they were poured. The first one is the pier under the kitchen floor being test fit with the jack before wrapping.
This is the footing under the dining room all wrapped up The screw part of the jack installed.
This isn’t the first time I’ve worked with concrete, but building these took a lot more planning, effort and time than I thought it would. Mad props to people who work with concrete for a living. Having said that, I feel much more comfortable planning my next concrete project which will be pouring a slab behind the garage.