French drainage, drainage around pool?

Jump to latest Follow Reply
R

Ralph III

0
Jan 27, 2018
139
Mobile, Al
Hello Everyone,
I am contemplating adding some drainage around my pool and would like your thoughts. Our backyard slopes downward where the pool is. So there is about a 3ft drop from the back of our house to one side of the pool which is 20ft away. I would like to address this runoff and an underground stream.

I am going to install gutters on the back of the house and drain the runoff to the back of the yard. So this will be a big benefit. But what else to do?

1. Should I install brick pavers along the edge of my concrete deck to dam up the water which runs off the deck? I could then install drains in various places and drain this runoff away from my pool versus letting the ground soak it up. This of course would only suffice to drain water coming off the deck.

2. Should I instead run a french drain along the side of my concrete deck? This would help drain water coming off my deck as well as water coming off the yard? This would seem the best solution BUT how would I insure no water draining off the concrete deck would seep behind the french drain and run under the deck, which is what I am trying to avoid?

3. Would you do both or is that overkill? I realize you cannot see my yard but I just want to remove as much runoff as possible.


Lastly, I had the pool liner replaced last week and we discovered a small underground stream running beside or under my pool. They had to install a pump (submerged) in the deep end and constantly pump the water out in order to make necessary repairs and then install the new liner. After all the work was complete and the pool nearly full, they then unplugged the pump and hid the cord behind the liner in one corner. The pump will only be used again when a new liner is installed.

This seems to be a common issue. Would you do anything to address this underground stream because my pool contractor didn't seem to think it needed addressing or could be. I mean would you install a deep french drain beside the pool or would you consider vertical french drains? They were pumping about 1 gallon per minute of spring water while working on our pool, btw.

God Bless,
Ralph
 
Ralph,

Seems like you should be able to install a combination French Drain and Surface drain in the same trench.. At the bottom would be a french drain to collect the ground water... Obviously a perforated pipe wrapped with ground cloth and buried in a rocks or gravel.. At the top of the trench, would be a solid pipe that would be connected to surface drains to collect the surface water and route it around your pool.. The depth of the trench, and amount of gravel, would depend on how much ground water you want to remove..

I had the same basic ground water issue with my gunite pool.. The two uphill sides now have a 18" wide 5 to 7 foot deep trench filled with gravel. The whole thing is about 50 feet long, about 25 feet on each side.. In the trench are perforated pipes that lead to a 10 foot deep pit that constantly fills with water even in the middle of the hottest summer. At the bottom of the pit is a sump pump with float that runs 24/7.. The pump removes all the water collected by the french drains.

Thanks,

Jim R.
 
water is going to saturate the earth around the pool no matter where you collect it from. If you had groundwater coming in while doing the liner swap you either have an underground vein or the ground could still be rather wet from recent rains. In any yard water will collect if its there in the deepest open area, in your yard its your pool. when the liner is in and the pool full of water the weight counteracts it and keeps it somewhat away. catching surface water helps alot, but you will never keep the bottom dry without a perimeter drain around the concrete collar going to daylight or a sump pit. if you have been in the house a while or had the pool built and are changing the liner you dont have a major issue if your liner has never floated due to ground water.
picture a square pool with 15 feet of concrete decking all around it and a drain on the edge of the concrete catching the runoff. when it rains the water will eventually seep down outside the concrete deck and go sideways because the dirt is drier and acts like a sponge pulling it towards the dry earth around the pool. this gets worst with clay soils or layered soils that have poor draining layers in them. anything you can do like underground leaders from your downspouts away from the pool, french drain, surface drains, etc will help and are good ideas if you think you have a problem. be aware most drains installed by a DIYer with little experience dont last long, its not that simple to put a drain in and properly bed the pipe in gravel and use the right fabrics. if you are thinking about the cheap black corrugated stuff in the big box store dont bother it will collapse and be clogged in just a few years
 
Thanks for all the replies.

JimRahbe I had decided to do exactly what you stated.

1. I am going to install 3in pvc pipe, with slots cut every 1in or so at the top, around my entire pool decking. The pipe will catch the runoff coming off the deck and flow into my pools overflow line. The overflow line drops pretty drastically down hill so no issues with any of the overflow going into the swimming pool. This pipe will be covered in a rock bed with brick pavers on the outside. I will use a crack isolation mortar at the top of the pipe to create a cup, so no water can seep behind it. Essentially, I will have a rock bed around my pool with some plantings so it will be nice.

This sounds a little expensive and like a lot of work but it's really not. It won't take much mortar to make a cup shape to catch the water and I can do that fairly quickly. Home Depot sells a good crack isolation mortar that adheres excellently and will expand/contract. I've used it for outdoor tile patios with excellent results. I am getting all my pavers for free, so no cost there.

2. I am going to then add a french drain on the hilly sides of my pool that will drain down hill.

3. I will also add gutters on the back of my house and be able to drain those via corrugated pipe down hill and hidden behind hedges. So I won't even have to bury that.

We just purchased the house last year and the liner I had replaced was probably original to the pool, so maybe 15 years old. So digging a deep trench or installing vertical french drains may be unnecessary and is in fact how my pool contractor felt. I still may consider doing it in the future though.....


JE Flogan. Yes, I'd recommend putting in some sort of drainage and make sure the earth is packed well before they install your deck. Otherwise, the earth will settle and you will get voids underneath your deck with possible settling as well. I do not know about your area but underground streams can be found at the top of the hill as well.

God Bless,
Ralph
 
Last edited:
Hi Ralph,

May I suggest going to the NDS website? They have great info there, including calculators so you can be sure you are using the correct size pipes etc. for what you want to do. www.ndspro.com Good luck. I installed some drains at my house to prevent water from accumulating in my widow well (from patio runoff after building my pool). It's labor intensive but work you can diy and save a ton of money. I have a 3 foot slope but coming toward the pool then towards the house (see my avi, I was standing on top of it when I took the picture). Best of luck!
-Chris
 
ralph when you install any type of perforated piping that is drilled or slotted the holes go to the bottom. i know it sounds backwards but its the proper way. the water still flows inside the pipe like normal even with holes or slots
 
Yes great information.

I'm confident the 3in pvc pipe that I will be running around my pool will be sufficient for deck runoff. I'm using that instead of channel drain because it will cost me significantly less and will look better for what I am doing.

I will then install some french drainage between my home and swimming pool which brings me to a major point in this post. I realize the holes are supposed to be pointed downward but wouldn't it be most beneficial to lay the pipe on a less porous material (clay/plastic) versus laying it on a layer of highly porous material (gravel)?

I want to remove as much water as possible away from my pool and home. So To me putting down a layer of gravel first and then laying your perforated pipe on it would be detrimental because a large percentage of water is going to be allowed to soak into the earth directly underneath your french drain. The point I am making is clearly seen at 4:34 of this VIDEO. When he hoses down the french drain notice that about 80% of the water is actually flowing underneath his french drain and not actually within his french drain. My ground is such that it will absolutely absorb all of that water and that is what I am trying to avoid.

Wouldn't it be more beneficial for me to lay a layer of compacted clay first and then lay the perforated pipe surrounded and buried under gravel?

God Bless,
Ralph
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply