Details and perfection. In the formative years of my life when I started working at the age of 13 I always had jobs that demanded perfection. The first one was when I started working at the family tool and die business. Everything there was done in thousands of an inch. If you were off even a half of a thousand than you just ruined a week’s worth of work on the milling machine. I found that out the hard way. After graduating high school I had the yearning for travel and adventure and joined the United States Marine Corps. From the first moments of stepping off the bus details and perfection was pounded into your brain. Hours were spent on the drill field that perfect practice created perfection.
I cannot stress enough how important a geotechnical engineer is to your project. He will set the tone for your pool structure, hardscape and landscape. Get a soils report done on every project whether you build a pool or a landscape. The soils engineer can advise you in the report what type of soil you have. We deal with a lot of soil that ranges from expansive to sandy. Knowing what kind of soil you have will dictate your rebar and concrete in your watershape, decking, footers, how much class to road base to install under your pavers. Address what kind of drip irrigation to use for your plants and your irrigation schedule. It’s not uncommon to take a foot or more of expansive clay soil out of a yard and saturate the clay to a 30% moisture content before laying down the road base for a deck.
When it comes to shotcrete, there seems to be an Industry debate between dry vs wet. It’s all in the application, and when applied properly- you will achieve the same result. The minimum ACI requirement for swimming pools is 4,000 p.s.i., 4,500 p.s.i. for high content of sulfate in the soil, (This is why soils reports are so crucial) and 5,000 p.s.i. for salt or brackish water. The higher the strength of the concrete the more binder (portland cement) it has in it, the less water will migrate thru the concrete. That’s why there is a minimum. It is very important to have a planned time frame in which you place the concrete. 90 minutes from when the water hits the portland cement to the time we shoot it out. I’ve sent trucks back or cut trucks short if they exceed that time limit. Wet down the dirt walls and floor so the dry earth does not suck moisture out of the shotcrete. Once you place the shotcrete, spray down the entire shell with a silicate based curing agent. This fills up the air bubbles that are the voids in concrete to help retain the moisture and helps with shrinkage cracking. As soon as the concrete reaches the correct temperature and after spraying on the curing agent; set up soaker hoses on a timer and start keeping the shotcrete moist. Always follow the minimum 2 weeks of curing time before turning off the soaker hoses.
When possible- it’s best to use #4 (1/2”) 60 grade rebar for the base grid. A #3 (3/8”) rebar because it is smaller, will bend easily when your plumber, electrician and shotcrete crew is stepping on it. Using the #4 gives a better shotcrete application since it doesn’t vibrate it when applying the shotcrete, therefore cutting down on the possibility of shadowing the shotcrete around the rebar. The 60 grade will allow you to use less rebar when required to use surcharges. There can be a specific way in which to shoot the pool. Always shoot your thickness and don’t layer it like a cake. If there is any rebound from the application, it falls on a completed floor instead of under the rebar. This will tell you to start with the area of the floor first. Part of the beauty of shotcrete is the watertight application that it will give by compacting the mix together when
being shot. If you have a hard time convincing your crews to do this, then using a vibrator should help to consolidate the mix. set up soaker hoses on a timer and start keeping the shotcrete moist. Always follow the minimum 2 weeks of curing time before turning off the soaker hoses.
Hydraulics are often overlooked in Watershapes, besides the structure, it’s one of the most important factors in creating a unique build. There are plumbing codes that are set forth by the APSP that require no more than 6.0 FPS on the suction side and 8.0 FPS on the return side. I like to follow the standard of 4.5 FPS on the suction side and 6.5 FPS on the return side. Aim for a 1.5 FPS at the suction outlet. No matter the pipe size at the suction, always go up to a 4” pipe at the penetration point. Your suction velocity will decrease significantly. Try to play with using variable speed pumps on every application. This will create versatility, and with the new, lower rated variable speed pumps, you can power water features at a very low speed with proper sized plumbing. The heater and filter are the major restrictions of a flow. A neat trick is to use a heater bypass valve that only lets water run thru the heater when heat is called for. This helps keep the wear down on the heater. When a need for higher speeds is called for; you will want to bypass some water past the filter, so more flow can get back to the pool.
This is only done when running the pump at a higher speed to activate a chemical system and is only for a short period. Water is still going thru the filter but not as much.
Pulling this intricate, unique spa and pool design together- is the wonders of the toe kick! Using multiple suction outlets for each pump is a key factor is functionality. This will insure that even if the pump is pulling more GPM than the cover allows, you have more than one outlet. Three to four outlets are a good start, especially on walls. Typically, outlet covers have a lower flow rating on the wall versus the floor. In the spa, use two channel drains and split them on the same line; this creates a toe kick under the bench that tucks the drain under the seat. This hides the drain and uses 4 suction outlets on the same line.
My whole philosophy when it comes to hydraulics is to move a large amount of water as slow as possible thru a pipe. The days of 2” plumbing should be abolished! Stay tuned for the completed project details of this rare Watershape design.
Contact me anytime for any questions.
GRANT SMITH SWD Registered AQUA-LINK POOLS AND SPAS CARLSBAD, CALIFORNIA
grantpools@gmail.com
