Posted by Simon

Footings, Day 3, First Concrete

Today was day 3 of the footings… Our first day pouring concrete on the site.  The actual work was really all done in about 2 hours, half an hour if you just count the concrete pour time, so it is hard to call it a day.  The inspector, Dale, needs to check the footings before the pour and his MWF 10 to noon schedule meant we couldn’t fit this into Monday afternoon like the footings guys wanted.

Here is today’s timelapse video;

Thunderstorms were predicted for 1:00, so I called the building inspector to see if he could put me early on his rounds.  He agreed and put me first.  I texted Doug Dysert by 8:30 and hoped that would be enough lead time to move the pour earlier…

The inspector arrived just after 10 AM.  Keep in mind, this was my first inspection, so I was a little bit nervous.  The first thing he did was check out my posted permits.  Then he went down into the excavation and gave the forms a good look.  The inspector was actually very friendly and said the design was a “work of art” and the execution was “very well done”.  He found a couple spots where the rebar was a bit too close to the boards (there is supposed to be at least 2” between the rebar and the forms) and told me to sort that out before the pour.   We chatted a bit and then he handed me my “Inspection Notice”, with “approved” written on it.  He left by 10:15.

I texted Doug to say we were all ready for concrete, but it turned out that the concrete was scheduled to come at noon anyway.  Two of Doug’s guys (Don and Chris from the previous day) arrived at about 11:45.  The concrete mixers (two of them) and the pump truck all arrived around noon. It was pretty awesome to see the pump truck extend its huge feet and then unfold its 135 ft arm.  I wish the timelapse camera had been angled to catch it.

PumpTruck_Cropped

The concrete pump truck was pretty huge.  Its 400 horsepower Cummins diesel motor powers 4 powerful pumps that push the concrete at 4800 psi.  The operator told me that he could pump up to 210 yards per hour, but he had it set on the slowest possible setting for my small job. I got my order slip from the driver to confirm that it was 2500 PSI concrete with a slump of 5 inches.  It had the ¾ inch natural stone aggregate (6A) along with sand and fly ash.

Fly ash is what Charles Dickens would have seen coming out of the smoke stacks of dirty coal factories before they started capturing it.   Trapping that pollutant it in concrete is a good thing.  It is also pretty much free (waste product) and replaces some of the Portland cement, which has high embodied energy (and cost).  Its tiny particle size increases workability (think tiny ball bearings) of the concrete, so the water content can be reduced, which increases strength and durability… It is really a win-win additive.

 

Then the clouds parted and the sun came out.  The concrete got pumping and things went pretty fast after that.  They pumped out most of the 23 cubic yards of concrete in about half an hour.  I don’t think the crew had enough people to keep up like they would have preferred.  I jumped in to help with the screeding.  Even the pump truck operator helped moved the concrete pipe around when he got tired of waiting.  The concrete was pretty thick with ¾ inch stones.  None of the footings blew out, but it did bulge in a couple spots, which used up more concrete than we were expecting…

For footings, they just screed, they don’t trowel or float.  Since the tops of the forms were already level, screeding was just a simple process of “sawing” a board back and forth over the top of the form to level it out.

 

We ended up needing to use the concrete that was in the bottom half of the long pipe to fill in the last bit of the forms.  The pump driver basically dumped it on the sand at the top end of the driveway and we had to bucket it over and down to the footing.  Don was using a 5 gallon bucket and I was using a 2 gallon bucket (only other bucket available), but I joked that at least I was filling mine up all the way.

With the last bit of concrete, I built myself a 5 gallon bucket rocket stove.  I made the inner form out of cardboard (the night before) and wrapped rope and saran wrap around it to “spiral” the flow.  My hope is that it will make a little flame tornado that will push even more heat into the concrete and increase the draft further.  I’ll make a separate post on that if it works. This concrete wasn’t exactly designed for high heat so it may not last long.

Then the rain came down again.  It was actually a line of storms, hundreds of miles long, all lined up to pass over my site, and nowhere else. They guys thought it would blow over soon and decided to wait it out in the truck.  I got in with them and asked how long we would be able to push the vertical rebar dowels into the concrete.  They told me not to worry about it, we had “hours”…

Well, nearly an hour later, and the township tax assessor called and asked me to drop off a copy of the plans.  The assessor had been out to view the site while we were not there and was totally confused by my footing.  She was only about 2 miles away, and I wasn’t doing anything right then, so I took the plans over to her.  I hope she devalues the home as much as my bank’s appraiser does.  Unfortunately, she seems to like it.

When I got back, Doug was on the phone.  Understandably, He didn’t want his guys to sit there waiting any more.  He said they could just drill the rebar in later (for ~60$/hr).  As I hung up with him, the rain stopped.  We went down to check out the concrete and found it was already too stiff to hammer the rebar into anyway.  It wasn’t my plan, but now I will have more time to carefully mark the position of the dowels, so it may be for the best.

Not sure if it was just the dollars talking, but Doug really didn’t like idea of the PVC tubes as rebar receptacles.  He pointed out that they would be a weak point in the connection between the footings and the rebar.  They do not have the strength or the grip.  I was more interested in the convenience because I don’t think I need strength or grip in that location.  Perhaps we were thinking about different locations.  I agree drilled rebar will be critical for the pillars under the concrete ribs.  Not sure if we will use the PVC when we get to the main footings, but I have 250 of these things cut and ready to go.

 

The rain washed off the concrete “crème” and left an exposed aggregate look.  I kind of like it and I think the shotcrete will stick to it well.  Another “day” done.

I still haven’t seen the bill (or paid anything).  In order to get a reasonable bid on this unusually complicated project, I had to get the bid based on “volume and materials”.  I thought that was safer than “time and materials” because at least the volumes were calculated beforehand.  Basically, I agreed on the cost per cubic yard for forming and pouring as well as the cost, per ton of rebar, for placing and tying the rebar.  But I do not yet know what he will charge for the materials (such as the wood, rebar, and concrete) or the total cost of the pump truck, or how the over-orders of material will affect the bill.  I am a tiny bit nervous about that.

Footings, Day 2. Level and Rebar

Today was day 2 of the footings.  We needed to level them and get the rebar in and ready for inspection.  Here is the time-lapse video for the day;


I figured we would be able to get it done in just a few hours, so I booked the inspector to come during his next available slot, 2 days away.  They Dysert Concrete guys usually work in a bigger town near by and didn’t realize that my township only has one inspector and that he only inspects for 6 hours a week.  They assumed they could finish the rebar, call in the inspector and still pour the same day.  Fortunately, we talked about the plan at the start of the day.  Some quick phone calls were made to stop the concrete trucks and then they got to work unloading the rebar and other equipment from the truck. Doug Dysert didn’t make it out today (so I still haven’t been able to give him a check or see a bill).  Baudilio, who I worked with the most on Friday, returned, but with two new guys; Don, a more experienced (20 year) veteran and Chris, the younger guy (9 years experience, but only one week with Dysert) who got the less pleasant jobs.

DysertTruck_40

Bau got to work on adding stakes around the footings while Don got to calculating the volume for the next days pour (I wasn’t surprised that his number was half a yard higher than my computer model predicted).  Chris, the new guy was unloading the truck.  I was just standing around without much to do.  So, I asked if I could use the motorized tamper.  It was kind of fun, as long as I didn’t try to back up.  I went around the “track” a few times until I felt like I was wasting time.

Talking to Doug on Friday and he mentioned that these motorized tampers are pretty expensive if you buy them new.  He said that the motors don’t last long, but the base lasts forever.  He always looks for an old one that doesn’t run, buys it cheap and then replaces the motor.  Good as new for less than half the price.

 

Then the more experienced guys got to work leveling the footings using a rotary laser level and a sensor on a measuring rod.  They set the rod on the top of the footing and the sensor beeps to indicate if it is higher or lower than the laser.  Fast beeping meant they footing was too high and needed to be lowered until they got a steady tone.  Slow beeping meant it was too low and needed to be raised.  Either way, they would screw the forms to the stakes at the correct height and continue on to the next section.

While they were doing that, Chris was cutting “rebar chairs”.  These keep the rebar at the right position in the concrete and out of the sand.  I “helped” by suggesting that he could probably cut thru more than one at a time.  I like to think I increased his productivity by 600% ;^)   Again, without much real work to do, I tried to keep myself busy by distributing the rebar chairs around the site.

After the forms were leveled, there were some gaps under them, particularly where they had been lifted up by several inches.  Again with nothing else to do, I got to work backfilling behind the forms with dirt so they concrete wouldn’t just leak out.  It turned out that I had not back-filled nearly enough and Chris went around behind me and did a lot more.

ConcreteSawMeanwhile, the other two guys finished leveling and switched to bending and placing rebar.  They had brought a manual rebar bender/cutter, but never used it.  Instead they used a concrete saw with a 12 inch grinding wheel for cutting (caution, that rebar is still hot for a long time after). All the bending was done “freehand” as needed.  They did have a rebar tie gun that is RebarTieGunsupposed to make the job easier, and it probably did, when it wasn’t messing up, or running out of energy, and it sure used a lot of tie wire (several reels worth).  I looked up the specific gun they were using and it costs $3,385 to $3,865 depending on the specific model.

Warning to anyone who wants to come out and help me: I think I will tie the rebar in the walls and ceiling with manual rebar tie hooks that use the little pre-cut and looped pieces of tie wire.  I wonder if an 8 year old and a 10 year can handle that?

The #4 rebar is pretty easy to bend, but not very easy to “curve” into the right shape, especially once you mess up.  I tried a few curves and decided I was hurting more than helping, so I stuck to the straight pieces with the simple bends.

The experience with free hand curving rebar was enough to convince me that such an approach would not be acceptable when I am working on the rebar for the vaults.  I will look into getting the rebar “factory” curved, or else build some sort of jig out of stakes to try and come up with a more precise method.

 

BGroundingRebarefore heading out there, I had looked up the coordinates where the “concrete encased electrode” would be.  This is basically using the rebar in the footing as an additional grounding rod.  So I set that up, complete with the rebar grounding clamps.

Lastly, I helped position some tubes in the footings so that we will have bleed holes, holes for the radon pipes and an exit to the septic system later.

We were done in just over 4 hours.

Next up, inspection to check our work and then we can pour the concrete.

Footings Day 1

Today was the first day of installing the footings on our Earth Sheltered Umbrella home. You can find the video here.

PlanCAfter the initial excavation, we tried to stake out the basement but the hole wasn’t big enough and we had to call back the excavators to dig a little bit wider (see the last post).  When I showed up on Friday (after a nearly a week off the site), I found that it was excavated well enough most of the way around, except on the north east side. On the west side, they had to excavate past the side of where the garage footing would have gone. The plan B had been to setup the footings for the basement and garage at the same time, but the over excavation cut into dirt under the garage, so we will need to save that for after the excavation. Plan C was to just form the basement footings and consider that practice for the rest later.

The crew from Dysert Concrete arrived on site around noon. There was a range of experience from one who had worked with Doug Dysert since they were both children, to the new guy who had started that week. No one on the team had ever done curved forms before, but they were all up to the challenge.

At one point, Doug sent the new guy to get the majibulator from the front of his truck. The new guy scrambled up out of the hole and got half way to the truck before Doug called him back and told him that there was no such thing as a majibulator.

 

FormLumberDoug had brought 12 inch lap siding for the curved portions of the form and 2x12s for the straight parts. My computer model had made it pretty easy to estimate how much of each material we needed, but due to the change of plans (not doing the garage), I ended up with some extra materials on site. The lumber yard was out of stakes Doug bought 1x4s and sharpened them on site.

The team decided that Sherri and I had done a good job on the stakes (within a quarter inch and enough extra ones to capture the shape) so they used them directly and started forming within a few minutes.

Doug had brought his copy of my plans and we referenced it regularly. It was a bit of a hassle because the plans incorrectly showed the footings as 1.5 ft wide in the main view (the more detailed views correctly showed 2 ft). This caused at least one mistake where we made one of the piers 6 inches wider than it needed to be. The plans also did not include the extra footing bits that the building inspector wanted, so we had to remember to add those.

FootingPlan
Doug had to leave part way through the afternoon for another appointment (so his crew will have work all summer), which left me responsible for the layout. Along the way, I made several mistakes that I realized right after the boards were cut and nailed into place. Some could be easily undone (such as the east pier where I just cut a board too long for where I intended it, but it still fit perfectly in the next spot. Other mistakes were not worth fixing and just added a little volume to the piers. The other guys (Baudillio and Jose) were pretty patient with me and only chucked a little when I would say, “No, wait, thats not right.” When I slowed down I made fewer mistakes. In total, I figure my errors only added about 4 cubic feet to the 18 cubic yards needed for the footing. That is less than 1 percent. (total concrete volume of the basement footings is 18 cubic yards (486 cubic feet) or about 73000 lbs).

I was very careful to place the inside boards so that each would only have 1 side and 1 end against concrete. This will make it much easier to remove them later.

 

The north east side of the site (top right corner of the scene, mostly off camera) was not excavated far enough and the guys had to dig it out manually… They ended up re-digging it numerous times because they didn’t throw the dirt in the right place (twice) and because the sand wall behind kept caving in and dumping more sand in the area. In the hot sun, it became a “laugh so you don’t cry” sort of thing, but we managed to get that last footing in and everyone left by 5:00 PM.

I noticed that when the guys wanted to keep their water jugs cool, they buried it in the cool earth. They didn’t build a little wooden box around it. Just sayin’

I also noticed that a couple of the guys put oats in the bottom of their water bottles… I wasn’t sure if they were eating those as a snack while they drank or had some other reason. The “new guy” asked about it and the others laughed and asked him if he ever had oat meal. “Same thing”, they said.

 

The laser level Doug brought was not working, so we just put the forms in for now and will need to come back next week to level them and add the ton (literally) of rebar.

When it was done and the guys were packing up, they said, “At first we thought the curves would be harder, but it all went pretty easy.” They all took pictures. I assume they don’t think most of their jobs are photo worthy.

If I did it again, I would use a saw table to make straighter cuts for the boards. The free hand cuts were pretty sloppy and made it harder to get the 90 degree angles for the piers. I guess it was good enough for footings work, but I don’t think it would have been any harder to make the more precise cuts and may even have made it easier to assemble and level. The hardest part would have been getting the table and power down into the hole.

 

Monday is rebar day, and hopefully I can get the building inspector out there on Wednesday so we can still pour this week… Now I need to think of what to do with the extra concrete. Any ideas? I am thinking a bucket rocket stove could use up a little.

 

 

Staking out the Basement

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 ;^)

IMG_2252_Basement_SitingWe 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 ;^).

TotalStation_BuildersTransitHopefully 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.

Meeting with the Building Inspector

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.

FrostProtectedShallowfoundationDale 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.

2011-03-sloped-vs-stepped-footings1

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.