The Video:
The Story:
These things usually start early in the morning… This morning, we were all ready to get these footings poured without any of the usual last minute running around. Three concrete mixing trucks were waiting at the bottom of the drive way as a dozen guys from Dysert Concrete arrived. The concrete pump truck arrived and while it setup, the guys were walking around and scratching their heads about my strange layout. Some were even taking pictures with their cell phones.
I showed some of the guys where the garage formwork had been done incorrectly and they started figuring out what to do. I was nervous because the first few guys clearly had no idea how to mount the groove form… But then a guy showed up who clearly knew what he was doing and took over organizing that work while some of the other guys got to filling the other forms with concrete.
The concrete mixer trucks dump their concrete into the back of the pump truck. The pump truck comes equipped with powerful pumps that can push the heavy concrete thru its 135 ft boom. The operator has a remote control box and walks around with a few of the of the concrete guys to control the movement of the boom and the flow rate of the concrete while they guide the end of the pipe along the form. It is quite something to hear that concrete falling down thru the pipe. For a big job like this, the pump truck really is worth the money. The alternative would have been trying to position the mix trucks around the site and push or wheelbarrow the concrete to the inner parts of the forms…
Initially, they overfilled the forms. The thin lap siding formwork was not strong enough and started to give way and lean out. I guess there were not enough stakes in the soft sand to hold back that much pressure. And after that, they filled the forms only half way and gave it some time to stiffen up a bit before coming back for a second pass. After the forms are filled up, they simply screed them off. It was amazing how the weight of the concrete pushed out even the 2×12 boards.
Meanwhile, the larger group were still working to properly finish the groove forms for the garage.
By the time the form for the garage was ready, they had already finished pouring the footings for the rest of the house. They started by filling the perimeter of the garage footing. They gave that a little bit of time to stiffen up because this was 18 inches thick and even more likely to blow out. While they waited, they pushed in vertical pieces of rebar along the middle of the floor to mark the floor slope.
Eventually, they started filling up the slab area, but quickly ran out of concrete. Another whole truck arrived and they dumped it out, but it didn’t go too far either. Along the way, they were screeding off the surface with long poles and leveling the concrete against the side of the forms and the rebar pegs in the middle. On the right side of the below picture, you can see the power screed that they used.
I noticed a slight bulge were my radiant floor pex tubes went under the concrete. I pointed it out and they said that it must be floating up. They said I should have tied it down every 8 inches… I thought that they (as experienced professionals) should probably have checked that before starting. Anyway, since we were waiting for the next concrete delivery to come anyway, they just gave the concrete a little time to stiffen and then pushed the pipe under (using long sticks) and pulled concrete (screeded) over it. I was still very nervous that it was still too close to the surface, but they told me it would be fine. I didn’t think until later that I could have put a piece of that 6×6 inch welded Wire reinforcement over the pex pipe to make sure that it stayed down…
Another truck load of concrete arrived and was pumped out. This time my concern was that the 6×6 WWR (Welded Wire Reinforcement) had been stamped down too much, especially at the front of the garage. Like the rebar, this welded wire reinforcement needs to be fully encased within the concrete to do its job. It doesn’t do much if it is trampled down under the concrete. I had been pestering the guys to try to pull up WWR elsewhere, and they made some halfhearted attempts upon each request, but at the front of the garage, where the slab sloped to the full 18 inches thick, it was so trampled down that I concluded it would be hopeless to ask them to pull it up… Instead, I waited until they got the got concrete in, and then I brought over two more big pieces of WWR and laid them on top before they guys had a chance to screed things over… Hopefully, these additional pieces stayed within a few inches of the surface where they could do their jobs.
With only one little corner left to go, they sent the pump truck home and we waited for the last concrete mixer truck. Most of the crew left also, except for two guys who were going to hang around and do the finish work on the slab.
After the last couple yards of concrete were in place, the senior guy used a power trowel to work the surface. The younger guy got busy working on removing the wood that held the groove form in place. Since things were now setting up quickly, my family and I rushed to press our hands into the stiffening concrete.
They took the power trowel over the surface 4 separate times and did a pretty good job there and on visible edges of the slab.
All in all, the footings and garage floor took 78 yards of concrete. The guys put down about 1300 lbs of rebar in the footings and I added another 530 lbs in the slab floor. That is just shy of a full ton, not including the fourteen 16×8 sheets of 6×6” WWR.
They came back the next day to remove the forms and cut grooves in the concrete… However, they didn’t want to cut up in the area where the radiant pex tubing had floated near the surface.
Mistakes:
On the whole, the footings turned out pretty well, and I appreciate that Dysert concrete was even willing to take on this job (many other companies didn’t even call me back after seeing the plans).
However, as a first time General Contractor, I made some mistakes here (just like every other phase of construction).
- I should have checked those forms better. As the rule of thumb goes, “put as many stakes as you think you need, and then add a couple more.” We didn’t have enough stakes in many places, especially on the bedroom side where the sand is softest. The bulges are a bit ugly, and they wasted concrete (more volume than needed). In one spot where the form leaned out, it actually affected the surface level of the footing and may give me a bit of a headache later… Oh well, at least these footings will be buried and never seen again. They don’t need to be pretty to do their jobs well.
- I did ask one or two guys if the pex tube that I placed looked right, and they just gave me a nod and a grunt… I should have got someone to check my work more closely. Then they would have seen my mistake (not tying them often enough). Things would have been more secure and I could have properly cut the slab to prevent cracks… As it is, I have 3 long (thin) cracks across the uncut portion of my slab…
- I should have complained about the level for the grove form. I saw that the east side sagged a bit in the middle, but I thought it would float up or be taken care of some other way… I didn’t say anything and now I need to deal with water pooling in that area. It won’t matter when I am finished the Quonset and grout the groove, but in the meantime, it is annoying. If that water freezes, it could cause damage. It could also rust the bottom of the Quonset steel before it is grouted…
Generally speaking, you need to speak up about concerns and get them addressed before the concrete gets poured… It is too easy to get swept up in the frenzy when there are so many things happening on the site.