How To Build A Concrete Pool Slide

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(Based on the book “All About Concrete Slides!”) Swimming pools are awesome! But swimming pools with a slide are MORE awesome. That’s if they’re built right. If they’re not they can be a real pain in the butt. Literally. And if they’er built really bad they might even kill you if you go flying out of one.

For decades I’ve been building fake rock concrete pool slides. Long ones, short ones and ones with turns. I’ve repaired and remodeled them too. Oftentimes trying to make them safer and more fun to ride. I’ve put them on hills, on flat ground and squeezed them into places that were a tight fit. And when you rode one slide I made you couldn’t even see the end of it when you started. It was completely hidden behind bushes until after you made the turn. I’ve made grottos and caves with slides on top of them and hidden them next to waterfalls as well. Just about everywhere people wanted one I built one. I’m even writing a book on slides which you can pre-order, (and get a discount!) before it is launched by going HERE

What’s crazy is that no one taught me how to make slides. Even the engineering details only address how much steel would be needed and the required thickness of the concrete and some basic dimensions. No mention of the degree of pitch, angle or steepness of the slide or number of allowable turns or bumps. Truth is there are guidelines on how to design slides. They were formulated in 1976 by the federal government.. So they’ve been around for decades. I was just never told about them by anyone. None of the pool building companies who I worked with brought them up. They just pointed and said make the slide there… So what did I use? What were my guidelines? Well, common sense. But a common sense informed by years of snow skiing.

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As a skier I new all skiers control their speed by turning. At least where the slope is steep. They go back and forth across the “fall line”. This is the path of travel a ball would roll if you let one go on a hill. The closer you travel to the fall line the faster you go. This is true of our slide riders as well. So when I began building slides that needed to zig and zag, (go from one direction across a hill then reverse direction to the other) I took into account the lead in to the turn, its pitch or angle so that the rider would be going at a speed allowing them to navigate the turn safely. Some of these slides were pretty mellow. Others where a scream. But all of them were and are safe and fun.

KINDS OF SLIDES
Basically there are (4) kinds of slides. 1 - STRAIGHT SLIDES, 2 - “C” CURVE SLIDES, 3 - “ZIG ZAG SLIDES”, 4 - MULTI-TURNING SLIDES. Straight slide are, surprise!…straight. And some I’ve seen should NOT have been built straight. They were too steep and the riders picked up speed so fast that they risked falling backwards and hitting their heads on the concrete slide surface. Not a good thing. Lesson? They should have been designed differently or shouldn’t have been built. Yes, some places shouldn’t have slides.

THE “C” SLIDE
When the hill or slope you’re working with, (or if you‘er building an elevated slide) isn’t too steep, (15 to 20 degrees or less) the safest slide design is a “C”. This is where the slide is one big curve in the approximate shape of the capital C. The riders can anticipate what’s coming more easily because the ride is consistent. No bumps, turns or changes. This is my favorite design.

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THE ZIG ZAG SLIDE
As mentioned above this slide starts going in one direction, (ZIG) and then turns and goes the other direction, (ZAG).

THE MULTI- TURN SLIDE
With these slides the riders must navigate more than one turn. This can be a challenge. As speed increases slide riders ability to respond to the new turn can cause them to roll over, flip, or tip. None of which is good. However if the speed of the rider is mellow giving them ample time to respond to the forces of inertia these slides can be a blast. But the key again is speed….

THE KEY COMPONENTS
In building a slide the key components that must be considered are the ELEVATION CHANGE, (height above the pool at the slide starting point) the second is LENGTH. The third is the CURVE or CURVES of the slide. The higher the slide is the longer it needs to be to allow for a more mellow pitch going into the turn and then once out of the turn leading to the pool. If the slide is too short with a high elevation staring point the speed will be too high when the rider hits the turn and could fly out or tip over. Both very dangerous situations. With the Curve design it must accommodate the limitations of the hill and elevation drop. If a “C” slide is built on too steep of a hill the speed that could be generated by the rider could become unsafe. However “C” slides are generally more safe even at higher speeds so the key is rider stability. Get that right and you’re risk of a mishap is lower.

RIDER POSTURE
The other component is rider posture. How riders ride GREATLY defines how they will experience a ride. If they approach their ride like they tell folks at waterparks, (layed back hands crossed behind the head or chest, the rider will be more stable and can better handle whatever the slide generally brings to them. If they sit up then they are vulnerable to tipping over side to side and hitting their head if a turn(s) is involved. Also some slides might also have obstacles that could be hit with feet, knees, arms and elbows if they leave the tough space. So keeping all of that “inside the vehicle at all times” is a good strategy.

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Once the slide Layout has been determined the foundations or footings must be dug. Then the rebar steel must be installed along with forms of some sort. I always try and keep the amount of concrete down to save on the expenses so I’ll install pegboard at times to limit the thickness of the slide wherever possible.

Once the rebar is ready the concrete or shotcrete can come. We shoot the slide, carving it in a half pipe fashion along with any faux rock that might be incorporated to help hide the slide. Then we let it cook for a few days. I then fill in any rough parts of the slide with a mortar mix and she’s ready for waterproofing. After that the final smooth mortar slide coat is applied and color is added. (the feature gets painted)

THE SLIPPERY STUFF
Once the slide is done there are two approaches to the slide surface treatment. It can be ground down until it has a polish to the surface after which a wax gets applied . Or it needs to be covered with a coating that make the slide slippery when water is added. I’ve always taken the second approach. Using a polyurethane.

LIMITATIONS
Concrete slides are very durable and will last for decades. The surface coatings of the slides on the other hand don’t. They do wear out and need to be re-applied. And that can occur in a year or two if the slides are not built as I’ve outlined above. Moisture can infiltrate the concrete from sprinklers or from around the slide feed pipes causing delamination of the coatings. Heavy water chemicalization can also impact the coatings as well as the angle of the slide in relation to the sun. More sun, more damage. Also running the slide everyday can be harmful to the coating bond due to the expansion and contraction of the slide resulting from the heat of the sun and cold water. So I don’t recommend that.

In summary concrete slides are amazing creations that can provide years of fun in the sun experiences for people of all ages. And when done correctly be a blessing to multiple generations of riders. Build them wrong? Well that’s a whole different matter. So let’s build them right and watch the smiles and laughter begin… :)

- Dave

PS: Don’t forget to pre-order a copy of my upcoming book ‘All About Concrete Slides” due out at the end of the year.

Dave Henderson1 Comment