I've decided to try my luck at an ICF pool.  Some of the older forum members may recall that I did an ICF storm shelter (2011) and house (2013).

www.greenbuildingtalk.com/Forums/ta...fault.aspx

I've been saving up for a pool the past few years and am finally ready.  I had considered taking the easy way out and hiring a pool company to install a traditional pool for me.  However, after meeting with and getting quotes from a few different local pool companies, I wasn't happy with any of the designs or prices.  Having had some success with my previous projects, I figured I’d try an ICF pool. 

After talking with the ICF sub from my house build, we decided to go with a one-side ICF form (Nudura One), instead of the standard 2 sided foam forms.  We felt the plaster (or pebble in my case) pool finish would be better applied directly to concrete.  I know there are techniques to apply the pool finish to foam, but I don’t know that the durability and longevity is the same. 

I’ve come up with a pool design that I am happy with and we broke ground this past week by putting in 37 concrete piers.  The clay soil around here just moves too much with the moisture fluctuations to build without the piers.

Here is a look at the property with the pool piers going in:  www.youtube.com/watch?v=4xGSOOIW8Vc

I have been very happy with the ICF house by the way.  I ran a meter on my geothermal HVAC equipment for a full year, and the cost to heat/cool the 8800 sqft house averaged less than $100 a month. 

I’ll try to post an occasional update for those interested. 

Nice place!

Hope the pool comes together nice for you.

Have you made sure that the pool isn't going to add any sort of unsupportable outward pressure on those retaining walls?

I know, your home is mostly downward pressure.

But a full pool is pushing laterally too.

I did get some recommendations from an engineer on the pool walls.  There should be enough steel in the sides of the pool to keep them from moving laterally. 

Also, the retaining wall will be 6+ feet from the sides of the pool.  It would probably take some significant movement in the pool wall to affect the retaining walls.  The piers on the pool extend 15-18ft down and are belled (wider at the bottom).  That is well below the level of either of the retaining walls.

There is enough extra capacity in my geothermal pond loop where I could plug the spa and pool into the system.  It would be able to keep the spa warm and heat or cool the pool mabye 3-5 degrees.  The ICF will help a little with the temperature regulation of the pool if I ever do try to condition it.  

Has anyone here done an ICF spa?  Seems like a good application for it.  I plan on an octagon shape, but don't have any detailed plans drawn up yet.  Any good references or plans out there?

Here is an overview of my layout.  The top right octagon outlined in red is the spa.  The pool is outlined in blue (shallow rectangle on the right and deep end on the left), and the solid red octagon bottom left is a basement (pool equipment), first floor outdoor kitchen and 2nd floor balcony/slide entry/jump ledge into the pool.  

I'm always happy to hear feedback, ideas/concerns if you have them.  

 

We started a pool in our basement during our build but haven't finished it yet.

https://photos.google.com/search/_p0xdb09f94686c8b5e2_Ann%20Arbor/photo/AF1QipNhQzl9DczDvo2zgnwd6JIDpMRXi2rnbd4vfAXv

Good luck, don't really understand the piers concept use on a pool because the load is already spread out over a lot of surface area. Seems like piers would create point loading and cracking but I am no expert.

Posted By newbostonconst on 07 Feb 2018 11:33 AM
We started a pool in our basement during our build but haven't finished it yet.

https://photos.google.com/search/_p0xdb09f94686c8b5e2_Ann%20Arbor/photo/AF1QipNhQzl9DczDvo2zgnwd6JIDpMRXi2rnbd4vfAXv

Link not working it looks like. I lived in AA for a few years. Nice to see well built homes being constructed there!

Posted By newbostonconst on 07 Feb 2018 11:33 AM
We started a pool in our basement during our build but haven't finished it yet.

https://photos.google.com/search/_p0xdb09f94686c8b5e2_Ann%20Arbor/photo/AF1QipNhQzl9DczDvo2zgnwd6JIDpMRXi2rnbd4vfAXv

Good luck, don't really understand the piers concept use on a pool because the load is already spread out over a lot of surface area. Seems like piers would create point loading and cracking but I am no expert.

Remember, his lot is compacted soil over waterlogged compacted soil.

While it's generally stable enough to walk on, something the weight of a house or pool is going to squeeze that like a wet sponge, causing movement of water in the soil settling as water evacuates.  Likely UNEVEN settling (Which Would Be Bad).

The piers actually break up the downward load  along the vertical plane.  Part is just being borne by the bottom of the pool slab itself.
Part of it is being borne by piers (which are driven to several different depths)

Yay! I'm so happy to see you posting and updating us. I actually had just gone through my old emails and was looking at the plans of your house you sent me. Was curious how everything was working out. Anything you'd change?

Posted By Amanda Moen on 14 Feb 2018 08:16 PM
Yay! I'm so happy to see you posting and updating us. I actually had just gone through my old emails and was looking at the plans of your house you sent me. Was curious how everything was working out. Anything you'd change?

 

I am very happy with the ICF house.  The energy efficiency, noise reduction and strength simply can't be beat.  I can't think of any major changes I'd make in the construction or design, but can come up with a few minor changes. 

First, I had a lightning rod on the tower with just one ground wire going down.  There was a lightning strike to the tower about a year ago.  I think the rod took most of the power down, but some of it found alternate pathways through the house that caused damage.  I've since added a system with 4 more ground rods and 8 additional lightning rods to the lower roof (all wired together).  I also put in a whole home surge protector.  The house is the tallest structure for a good 1/2 mile in any direction, so I know it will be hit again. 

Second, maybe consider a different brand/model of the direct vent propane fireplaces.  The current ones produce more soot and require more cleaning than I expected.  I'd probably also change the location of a few light switches around the house (if I did it over), but that's  about all I can think of right now.  

I'm using the same brand of block (Nudura) and same ICF subcontractor for the pool.  We are planning the one side forms for the pool (foam on the outside of the pool).  I'm thinking I may use the standard 2 side ICF forms for the spa, but still trying to think that one through.  

Honestly, you're probably better off going single-sided for the spa as well.

You won't have to worry about surface finishes lifting off as much if water gets behind them. Nor about cooking yourself some EPS soup...

Posted By Dilettante on 15 Feb 2018 04:06 PM
Honestly, you're probably better off going single-sided for the spa as well.

You won't have to worry about surface finishes lifting off as much if water gets behind them. Nor about cooking yourself some EPS soup...

Dilettante,

I appreciate the input.  The reason why I'm still up in the air on the spa construction is because I haven't decided whether to go with a traditional propane heater or a geothermal heat exchanger.  I have the plumbing in place and enough extra field capacity in the pond to use geothermal for the spa/pool.  

Cost wise, the geothermal option would be more expensive up front (even with a tax deduction for geothermal), but have a lower operating cost going forward vs propane.  My guess overall, the lifetime cost of propane vs geothermal system is probably about equal.  

The downside to using geothermal is the system capacity.  A typical 5-6 ton geothermal water to water system can only do about between 60k-80k BTU.  A standard propane spa heater can do up to about 400k BTU.  That means it will probably take +/-5 times longer for a geothermal system to heat up a spa vs a propane system.  

With a one side ICF form I'll have to heat the entire mass of concrete in addition to the water (guessing about 50% more thermal mass).  A standard ICF form with insulation on both sides would be significantly more efficient and less mass to heat. 

So, if I go with the geothermal system, I'd probably try my luck with the double side forms just to compensate for the lower BTU capacity.  If I go propane, than the extra capacity of the heater would more than make up for the extra mass of the one side form.

The big benefit to using a geothermal system is that it would be cheaper to run and allow me the option to either heat or cool the water.  I could condition the pool in addition to the spa.  I wouldn't do that on a regular basis right now, but in 8-10 years when I get around to installing a solar panel system on a new ICF barn (or when they figure out nuclear fusion in 10-20 years), then it may be a year round option.

 

Are you planning on adding solar panels at some point in the future? I could imagine that you have enough roof space to end up net-zero.

With a plate heat exchanger you could use your Geo to heat the pool....when AC is on the heat goes to the pool.

Posted By Amanda Moen on 16 Feb 2018 04:24 PM
Are you planning on adding solar panels at some point in the future? I could imagine that you have enough roof space to end up net-zero.

That is the longer term plan.  I probably won't put solar panels on the ICF house roof, but in 10 years or so I'd like to replace the older house and metal barn/shop with a new ICF barn and full solar roof.  Hopefully battery technology will have improved enough by then to allow me to be fully grid independent at a reasonable cost.  

The current geothermal HVAC does have a hot water generator and produces hot water for the house when the AC is on.  It would probably not be worth it for me to hook it up to the pool, but is something to consider.

Hmm. Guess I'm just spoiled. I don't normally think about turning the spa completely off and letting it cool down.
I'm sorta spoiled, as a lot of my experience with these come from large, multi-collector-bank solar thermal setups where hot water is damn near free. A couple of them are comprehensive enough that all the hot water on the property (laundry, taps, bathing, 2 pools, and a spa) are kept bath water warm at the coldest.

Posted By Dilettante on 17 Feb 2018 11:43 AM
Hmm. Guess I'm just spoiled. I don't normally think about turning the spa completely off and letting it cool down.
I'm sorta spoiled, as a lot of my experience with these come from large, multi-collector-bank solar thermal setups where hot water is damn near free. A couple of them are comprehensive enough that all the hot water on the property (laundry, taps, bathing, 2 pools, and a spa) are kept bath water warm at the coldest.

For the near future, I'd probably just heat the spa on demand (rather than 24/7) to save on energy expense. Once I have a solar system set up (or nuclear fusion makes electricity dirt cheap), then I'll keep the spa +/- pool conditioned 24/7. I plan on living at this place for the next 50+ years, so I'm hoping the insulated pool will help with the 24/7 conditioning at some point.

An update for those interested.  The floor for the swimming pool and tower was poured last month.  We will hopefully start the ICF walls sometime in the next month or so.  The pool and patio will be a slow (year-long) project for me.  I’m doing it in my spare time and still working out details as I go.

The pool walls will be 10 5/8” thick concrete + 2 5/8” foam (on the outside of the pool).   The top of the ICF walls will be above the patio level, because I want a raised sitting bench all the way around the pool.  I figure the raised bench will help keep some of the debris, bugs and the pond frogs out of the pool.  It will also make it a little more difficult for small children (or adults) to accidently fall into the pool.

The ICF wall will be topped off with pool coping (probably travertine or cast stone).  It will be ~18” above patio level (a good sitting height).  The water level inside the pool will be about 6” inches below the top of the bench, and 12” above the patio/deck level.  Having the pool slightly above ground worked out better for the elevations around the house, adjacent retaining walls and pond. 

After the pool walls are up, I’ll be doing a large concrete slab around the pool for the patio foundation.  On top the concrete slab will be about 18” of crushed rock/fill, with travertine pavers on top.  The concrete base should keep the patio stable for decades to come.  The 18” of  fill will allow me to put in a French drain system and pool plumbing below the 10” extreme frost depth (for my area), but above the concrete slab in case I ever need to do any plumbing repairs/work down the road.  Finally, the fill will be topped off with travertine pavers for the patio surface. 

I still haven’t decided on a spa design.  It will be done separate from the pool wall pour, so I haven't put much thought into it yet.

I’d appreciate any feedback or suggestions from anyone who has done an ICF (or traditional) pool.  I’m still figuring out things as I go. 

Question. Are you going with borate-treated form for the wall exterior?

If not, you may run into problems with termites down the road.
Granted, they're not going to do much to the pool itself. But, digging around for food, they'll likely destroy the foam over time.

I hadn't really thought about insect control.  To my knowledge, Nudura does not have any borate additive.  However, termite risk is probably pretty low for my situation.  There are no trees or other nutritional sources for termites within 50+ feet of the pool.  Also, a large concrete and paver patio will completely surround the pool area. 

I've never seen any termites in the 15 years on the property.  Part of that may have to do with the heavy clay soil and the fact that 90% of the trees in the area are cedar.  Termites are not a fan of cedar.

That being said, fire ants are a big problem around here and I've read they can also be a problem with ICF foam.  The first year with the new house I noticed fire ants entering the outside walls in at least a couple spots. I began spraying the perimeter of the house 2-3 times a year after that.  The insect spray seems to have made a difference.  It might not be a bad idea to spray inside/around the ICF forms with an insecticide before they get filled with concrete and buried.

The pool walls are just about ready. Still working on the gazebo/tower basement (equipment room). Will hopefully pour next week if the weather cooperates.

Very impressive project. Not that it matters, but I agree with Dilettante about the one sided forms for the spa. Cover it and keep it warm. Solar hot water is simple in that climate and unless you are the one that perfects fusion, electricity is never going to be dirt cheap. You could have a small set up on the ground until you get your roof mounted system. Even with the propane for backup, in case you want to bring it up to temp in a hurry. Another use for any excess very hot water is for fire ant control. I've had great success with it and it isn't toxic. Just pour it right on wherever you see activity. I usually just heat a big pan on the gas grill. [propane] If you have an outside kitchen area or even just a gas grill, you can plumb it to the propane tank so you don't have to deal with constantly changing those small portable tanks. A little fossil fuel probably won't hurt too much but there's always photovoltaics to power an air to water heat pump.