Gunite Shooting Part 1

   Wasting no time, Joe and his crew came today for the first of two or three gunite shoots for the pool shell.  Late last week, they dropped off equipment and left a few trucks in prep for the shoot this week.  We had the skid-steer, gunite mixer/shooter, and some kind of generator or air compressor sitting on the pullout of the driveway over the weekend.  The skid-steer moved the machines to the back yard to be closer to the pool site.

   Here's the shooting in operation.  The machine in the middle would take bags of concrete in one hopper and the skid-steer would race to the front yard where they dumped the sand and bring up a bucket to dump it into the main hopper.  The corkscrew lift would mix the two and water connected via hose would add moisture.  The mix would dump into another hopper at the end of the lift and from there it would run out the large diameter hose to be shot at the pool.  The bags of concrete on the left are labeled "Saint Mary's Cement Type IL Portland limestone cement".  The internet says that IL Portland cement uses more limestone content than normal Portland cement.  The bags on the larger stake are labeled "Onecem type IL Portland Cement" so they're both IL cement, which is supposed to have a lower carbon footprint than normal Portland Cement.  I'm sure there are other cement-based science differences for IL Portland cement, but it's probably not relevant to this pool.

   Here's another look at the equipment used for gunite shooting.  You can see the large Doosan 750 portable air compressor in the background near the house.  It has a large hose that connects to the gunite mixer, but I think it's just for the actual shooting of the material.  The gunite mixer itself has a gas powered engine to power the mixer and lift.

   Here's a shot of the pool from the deep end at the end of day 1.  The gunite was shot up most of the side of the pool, with the remaining portion to be completed the following day.  That second day shoot will require a little more accuracy since it will entrap all the stubs and skimmer boxes.  The left side of the pool saw some erosion behind the metal so they slipped a piece of the plywood behind the metal to reduce the amount of extra gunite needed to fill the void.  Since there's a water return penetration at the space, it will eventually be excavated for plumbing access and backfilled, so I'm not worried about the ground integrity when it's all done.  Also, this curve will feature a small planting bed so the soil will need to be amended anyways.

   Here's a shot of the deep end with the Eclipse pool drain installed.  There are disposable caps on the round and center section which are used to block material and protect the drain.  These caps will stay in place until pool start up.  As predicted, the whole drain pipe channel was shot with gunite, encasing the pool drain pipe.  The gunite was troweled for shape but it's not a super smooth surface, which will come later from the plaster finish.

   The skimmer box areas saw forms placed around the whole assembly, using the wood structure installed by Eli as a guide.  It looks like the entire skimmer box will be encased in gunite, but the finished paver surface will sit on top of this concrete block.  The preinstalled drain pipe from the skimmer still exist the rear of the box form and is currently buried. 

   Some excess gunite was shot in the swim out step area, but the steps themselves haven't been formed yet.  The underlying shell needs a little bit of hardening before those are shot and formed.  I spoke briefly with Joe before they started work in the morning.  He requested the color plans so he could use them as reference, and said that the shoot will pretty much adhere to the plans.  The plans call for two steps, and while there's no code for riser height, he said he likes to make them about 8-10 inches in height, so there will be two swim out steps.

   Just like the swim out steps, the sun shelf hasn't been shot yet.  The bubbler remains uninstalled, but it looks like they left a notch in the gunite they did shoot to allow for pipe passage.  The plans call for three steps coming off the sun shelf, with the sun shelf itself being about 8 inches deep.  Joe said that the depth of the sun shelf will be dependent upon the coping stone because you don't want to have a really high step coming out of the pool.  Typically, sun shelfs are 8-10 inches deep and loungers that sit in sun shelfs can be 2.5 inches thick, leaving 6 inches of your siting area in water with your legs and most of your torso out of the water.  So three steps plus the sun shelf at 8 inches per step puts us at 40 inches, which is 3 feet 4 inches for the beginning of the shallow end of the pool.

   One of the skimmer boxes was installed at height and the other remains to be installed.  You can see how they cut the rebar around the box, and this one still needs the rest of the box forms installed.  The stub pipes were placed a bit below the water level and were cut through the form to be jammed into the dirt.  Eli said the gunite shoot should be take a few days to complete and afterwards, we would need to water the pool every day to control the speed of drying.  Online instructions state that the gunite should be watered at least 3 times a day for at least 14 days, especially if the weather gets hot.  The gunite should absorb much of the water sprayed on it and help with the curing.  Since concrete curing is exothermic, spraying water keeps it cool and prevents cracking.  I might need to get a sprinkler on a timer to handle the mid-day watering since I can't work from home every day for the next few weeks.

   Here's the thickness of the pool being shot.  It looks like the metal structure sits a couple inches below the gunite shell and there will be another half inch of plaster on top of that.  When I was leaving for work in the morning today, the crew was already on site prepping for shooting so I'll get to see how much progress they'll make today.  It's a little more precise for the rest of the pool and there's still some prep to be completed for the skimmer and bubbler, but if they move as fast as they did yesterday, it almost seems like they could complete it on the second day.

  Unfortunately, the driveway took some damage from all the heavy machinery.  It was a little expected and in general pool installation circles, there's not much that can be done about it.  It generally falls under the home owners responsibility to repair so I'll have to cut this part out and patch it, either during the 28 days it takes for the gunite to cure, or after everything is completed.  Pool deck installation will require more heavy materials to be moved and probably some machinery, especially for the boulder wall installation so I might just let this sit until the fall after everything is installed and the weather is cooler again.  Remember, the driveway was never really finished with a final top coat because we knew we would have heavy machinery driving back there for the pool and all the other remaining landscaping installations.  Even after the pool area is completed, we'll still need some retaining wall and steps installed leading to the back yard, two paver patios for each basement walkout, and a deck that goes around the garage.  I'll patch this area so it doesn't crumble more, but when everything is finally done, we'll probably get the driveway resurfaced and completed.

   That's it for this update, but I'm certain there will be another coming soon that will show the completion or near completion of the pool shell.  Afterwards, there will probably be a lull while the shell hardens, but it will pick up again for the final plumbing and finishing of the pool.