Saturday, our kids each had soccer games, one after the other. Each of my boys won their games (3 to 2 and 5 to 3). By the time the games were over, it was mid afternoon, we dropped them off with their grandparents and headed out to survey the basement. We were using a builders level that I rented, again. We had to do the job again because all the previous stakes were dug up during the excavation. Well, I should say most were dug up. Sherri had run some extra stakes further out so that we could re-establish the location of the center of the house. The excavators had been careful not to disturb those markers.
When we got there, it was kind of cool to be able to drive up our new driveway… Its the little things ;^)
We started with the long line that Sherri had marked out before the excavation. We tied some masons line between the stakes that she had placed 50ft on either side of the center (the excavation was about 60 ft across). We tied a plumb bob to the mason’s line at the middle point and let it hang into the excavation. The sand was also very soft and rough, so I spent some time flattening the area, especially around the hanging plumb, with my 10” tamper. I then positioned my marked concrete paver (90lbs) centered under the plumb and lined its etched angles up with the mason’s string overhead. Then we setup the builder’s transit over the paver (I finally have that setup process figured out after three rentals). Again, I used the overhead string (and the lines etched on the paver) to orient the transit. It took us about an hour of setup before we placed our first stake, but once we did, the rest went fairly straight forward. Since most of the key points for this design are positioned radially from the center, we just needed the transit for the angles and a measuring tape for the distances. This marked out the centers of the edges, then we offset these stakes by one foot (half the width of the footing) to get the true outer corners. In one corner, we use some Pythagoras (3-4-5 triangle) to square things up. We also put a lot of “extra” stakes in to make the curved shape clearer and topped it off by tying string along the perimeter of the footings. We actually had brought surveyors paint, but it didn’t work well on the sand.
The pit had not been excavated far enough and I had to do some manual digging along the way. The soft sand was easy to dig (I did all the work barefoot and pretended I was at the beach) but as I dug, the sandy wall would cave in and give me more to dig. I couldn’t throw the dirt out of the hole, so I tried tossing it “out of the way”. But I didn’t put it “out of the way enough” and I had to dig some of the same dirt again when I got to the next stake. Sherri thought that was funny. There were a few areas that had so much sand I just gave up and stuck the stakes in about where they would be. We called the excavator to come back and widen the excavation. That was a bit disappointing because it meant we would need to delay the start of the footings. Anyway, we got it all staked out by 9:20 PM (just before it got dark), but it was probably closer to 10:30 PM before we completed the long drive back and picked up our kids (an hour and a half later than planned), so we appreciate that my in-laws were merciful and hope they will still help us out next time ;^).
Hopefully the Excavator will go back and take care of the over-dig without disturbing these stakes or the centerstone marker (paver) too much and we can get to work on the footings. I found out that my footings guy uses a “Total Station” builders transit. It has a computer that does all the trig for you. We will let him stake it out next time. I just need to figure out how to transfer my drawings into the right format.
Friday, I met with the building inspector (Dale) to discuss his notes, especially about the footings and “special 3rd party inspections”. I also wanted to discuss the alternative to the step footings that my concrete footings guy wanted.
Dale started the meeting by saying that he had read my email (which included a detailed description of “frost protected shallow footings” and all the codes related to them) and that frost protected shallow footings were fine. I guess the plans simply had not been detailed enough to show that they were “frost protected”. Great. We got thru his other notes just about as quickly. I told him I would happily do the concrete encased electrodes, but since my footings should stay dry, I would also be putting in conventional grounding rods. He said, “of course.”
Then we discussed the “special 3rd party inspections”. He simply didn’t feel qualified or comfortable signing off on those parts of the construction. These included things like my precast concrete ribs, the rebar in the vaults and the shotcrete. He wants me to hire a 3rd party engineering company to certify that these are built correctly. Of course, this will be additional expense for me.
I tried to explain that I had already paid the engineer a lot of money to certify the design of the rebar and that it was normal to trust the strength of the concrete from the mixing truck. All the building inspector had to do was compare the engineers instructions with what we did. The inspector was not quite convinced, but said I could hire my previous engineer to help him with the inspection. Unfortunately, my original engineer (Ken) has closed his practice. I did try contacting Ken anyway and he told me he couldn’t do it. My inspector gave me two other large engineering companies to contact. The first, PSI USA, told me they wouldn’t work on a residential project and the other (SME USA) has simply not got back to me (it has been more than a week as of this writing). I asked my architect for suggestions and he gave me a name, but I have not managed to call that engineer yet (I have been traveling for work myself). I spoke with my shotcrete guy (Nate) to find out who he had worked with. He said that building inspectors never have trouble inspecting his pools. My inspector had already said this is different because the pool is up against earth, the water has no where to push the concrete. In my house, the earth is trying to push the concrete down onto peoples heads. Nate said that special inspections are sometimes done for large commercial jobs, but it would really cost me, both for the inspection and for his crew to make the test panels (tested destructively).
The notes Dale made on my plans also included a list of “additional” inspections. These were additional inspections that he wanted to do because my construction was so unusual. They included inspections when I set the concrete ribs, added the waterproofing umbrella, etc. I got the impression that I would not be charged for these, but maybe I am naive. I will ask directly the next time I get a chance.
Last, but not least, I asked about Doug’s plan to change the step footings into doweled footings over fill. Dale said he didn’t like footings specified by the engineer because they had a sloped bottom. He said footings should always be flat on the bottom (which does make reasonable sense even if sloped footings are actually approved by civil engineers.) He said Doug’s plan was fine, but I needed to extend the lower footing out by a foot and put a pilaster on it to better support the doweled footing. I asked about the fill and he said the footings could span a 2ft section of fill, but any more than that and I would need the fill to be “engineered”. I guess I will need to get that done, hopefully it is not to expensive. At least my sand should be easy to compact.
In the end, I updated my model to facilitate communication with my footings guy (Doug, sounds more like the name of an excavator doesn’t it?). I hope to meet with Doug tomorrow to come up with a plan of attack. I have agreed to start with just the basement footings and get the basement walls up and backfilled before working on the other footings. It changes my schedule a bit, adds an additional concrete pump rental and an additional footing inspection, but it does seem easier than trying to work around that sloped sandy excavation. Including that basement in the design really has complicated things. I will ask Doug about doing the garage footing at the same time so I can start on that Quonset hut sooner.
Buying the land, hiring the architect and getting all my permits were each big steps toward this earth sheltered home. But, digging a huge hole makes those other steps pale in comparison. Things are now very serious. Where I once had a nice green rolling hill, I now have what appears to be some sort of ecological disaster… Actually it looks a lot like a sand quarry. I look forward to restoring it again as soon as possible. There is no way to turn back now, I have to push through.
Prep
We only had to excavate the partial basement portion, just over one third of the site. The shape of the basement is like a half circle with a few bumps on it… Sherri and I started the day by staking out the perimeter of the footings. Then I had a chat with the excavators (Roe Brother Excavation). I had invited the footings guy (Doug Dysert of Dysert Concrete) to join the conversation so that the excavation would be done according to his needs. Since my footings are curved, he had already told me that he would rather have the excavation down to the bottom of the footings (easier to build curved forms on the ground rather than dig them out). But now I wanted his input on how he planned to create the step footings that would transition from the full depth basement footings to the slab on grade footings and how that would affect the excavation plans…
Doug said he didn’t like engineers “sloped” step footings. He said, “Maybe that’s how the specify it on government jobs, but that is not how we do things around here.” He would prefer that we build the basement footings and walls first and then back-filled before working on the slab on grade footings. I was concerned about building footings over fill and about making any changes that the inspector wouldn’t like. Doug said I should make sure the inspector likes those footings and everyone agreed my sand would compact very nicely. Doug also sketched me his plan for connecting the basement footings with the slab on grade footings. The next day, I took those to the inspector, more about that in a separate post.
Anyway, back to the excavation… Doug didn’t want a sloped excavation, but I was concerned about needing slope for the footings specified by the engineer. We agreed that a “double over-dig” would be OK. We would over-dig 4 ft around where the footings would go, and then step up 4 or 5 feet and then over-dig a second 4 ft out from the first. I figured it would give the shotcrete and waterproofing people space to work and would allow me to easily excavate for sloped step footings if I needed to. Even if it crumbles, it is essentially a 50 % slope, so it should be OK. Doug sprayed the 4 ft offset line (curving) around my original basement footing stakes so everything was marked out.
My favorite quote of the day (paraphrased)… “The problem with dirt is that is is all in the wrong place. For instance, here we have some dirt where there should be a hole. Some times you have dirt where there should be water. An excavators job is to fix these mistakes.” I would add to that every earth sheltered home owners fear… “Some times there is water where there should be a hole”, fortunately, that is probably not going to be an issue for me on this sandy hill site.
Dick Roe (an original Roe Brother) got thinking about how to approach the dig (you don’t want to dig your self into a corner) and Marty (a Roe Son/Nephew) got busy on my drive way. Meanwhile Sherri did the smart thing and quietly added center-line stakes well beyond the excavation area.
Lesson learned
We had made things hard on ourselves by outlining the curved project with curved offsets. Once the excavation got started and the stakes were dug out of the hole, it got harder and harder to remember what was going on. I couldn’t visualize it anymore and I have been staring at the plans for years, so I am sure my excavator had no chance. The hole ended up looking somewhat like an amoeba as the excavator tried to dig just the right amount, but not too much. It was also a challenge to deal with the growing piles of dirt around the hole
My excavator was kicking himself for not laying out the overdig with a rectilinear shape (like a trapezoid) around our curved plan. He would have been able to stake out the overdig easily and then dig it out with much less time spent scratching his head. Make sure to tell your excavator “the footings may be curved, but the excavation is all straight lines.”
The Excavation!
Here is a video of Sherri and I laying out the basement stakes and then the digger getting to work.
With the extra head scratching and time spent on my driveway, etc., they didn’t manager to finish the excavation on day 2. They came back the following morning and took care of it. By the second day, the excavator had decided that the site was too sandy for stepped sides and put in a slope for most of the way around (which is what I had originally asked for). He also added a ramp to make it easier for us to get in and out of the hole. He said that if Sherri and I found it was too small, he would come back and make some final adjustments.
We started with the long line that Sherri had marked out before the excavation. We tied some masons line between the stakes that she had placed 50ft on either side of the center (the excavation was about 60 ft across). We tied a plumb bob to the mason’s line at the middle point and let it hang into the excavation. The sand was also very soft and rough, so I spent some time flattening the area, especially around the hanging plumb, with my 10” tamper. I then positioned my marked concrete paver (90lbs) centered under the plumb and lined its etched angles up with the mason’s string overhead. Then we setup the builder’s transit over the paver (I finally have that setup process figured out after three rentals). Again, I used the overhead string (and the lines etched on the paver) to orient the transit. It took us about an hour of setup before we placed our first stake, but once we did, the rest went fairly straight forward. Since most of the key points for this design are positioned radially from the center, we just needed the transit for the angles and a measuring tape for the distances. This marked out the centers of the edges, then we offset these stakes by one foot (half the width of the footing) to get the true outer corners. In one corner, we use some Pythagoras (3-4-5 triangle) to square things up. We also put a lot of “extra” stakes in to make the curved shape clearer and topped it off by tying string along the perimeter of the footings. We actually had brought surveyors paint, but it didn’t work well on the sand. 
Hopefully the Excavator will go back and take care of the over-dig without disturbing these stakes or the centerstone marker (paver) too much and we can get to work on the footings. I found out that my footings guy uses a “Total Station” builders transit. It has a computer that does all the trig for you. We will let him stake it out next time. I just need to figure out how to transfer my drawings into the right format.
