Piers

[JJ_Tex]

Our lot is sits on top of a 15' tall retaining wall and the edge of our pool will be ~6 feet from the edge of the retaining wall. As such we are having an independent engineer review the plans and design the piers. The engineer is part of a large firm that does residential and commercial structures and is truly independent from the PB. This was recommended by our PB (which is why we went with him).

We should get those back on Monday and I'm hoping it is in line with the 16 piers 15' in depth from the pool bottom that the PB estimated in his bid.

Does anyone have experience with piers or building on top of a retaining wall? Any questions I should have for the engineer?

Fingers crossed all goes well with the engineer and we can start seeing the real work soon.

 

[Texas Splash]

Well, not for a pool, but we had piers installed last year for our house (garage). They had to punch those piers (1-ft segments) down to about 50 ft before finally hitting solid rock. So you might ask:
- Depth limitations based on bid
- Type of pier (steel, concrete, or combo)
- Warranty period

Good luck!

 

[kimkats]

I wonder if @bdavis466 has had the *pleasure* of having to use this kind of thing in any of his builds???

 

[bdavis466]

What is the construction of the retaining wall?

 

[JJ_Tex]

What is the construction of the retaining wall?

The wall itself is concrete/stone and was put in by the developer. When they built the neighborhood, they basically made it so houses backing up to either other were at different heights for additional privacy.

 

[bdavis466]

I would expect a wall that height to be a segmented retaining wall with Geogrid or underpinning which would be very problematic for your pool.

15' is really high for a conventionally constructed retaining wall of that's the case.

Piers are a good plan. Make sure you have VERY good drainage both around the pool and for the pool so it doesn't overflow.

You might ask if helical soil screws are an option and consider placing them vertically and horizontally.

You also might want to reach out to your insurance company as well...I imagine there is a house below you and the pool will definitely affect your premium.

Can you post some pictures of the yard and pool?

 

[JJ_Tex]

I don't have a ton of backyard pics, but these will at least give you a perspective on height since we can only see the top of the roof on the house behind us. The neighbors to our right have a pool, and the builder just put in piers every 10 feet. Our quotes varied wildly in #of piers with some even saying only putting piers on the side of the pool closest to the wall. Thats why we opted for an engineer to actually design the piers on what we needed. Seemed like a logical use of $900 for peace of mind.

Our pool builder expects the engineer to have 16 helical piers, and a depth of 15 feet below the bottom of the pool but the depth is just an estimate as they srew down the piers until they hit a certain resistance.

 

[bdavis466]

Ah, I was more interested in the other side. BTW that's a bargain for that type of Engineering

 

[JJ_Tex]

They had to punch those piers (1-ft segments) down to about 50 ft before finally hitting solid rock.
-

If they have to go down 50 feet for 16 piers, and they charge by the foot, I'll be able to fill the dang pool with my tears.

 

[JJ_Tex]

Ah, I was more interested in the other side. BTW that's a bargain for that type of Engineering

These may not be helpful either, but I snapped them of one of the retaining walls in our neighborhood on my way to work. Note that its not my wall, but one of the many in the neighborhood. This one is similar height to ours.

Edited - Got the kids to take a pic from the upstairs window. You can see the wall that runs along everyone's backyard.

 

[bdavis466]

Interesting, not what I had expected. I'd be really curious to know how they were built

 

[SPman]

Interesting, not what I had expected. I'd be really curious to know how they were built

How long ago was this development built?

 

[JJ_Tex]

How long ago was this development built?

Our house is 8 years old. We are the original phase of the neighborhood, which was probably developed 10-12 years ago. No known issues with the walls so far (600+ homes) and they keep on adding phases.

 

[kimkats]

So........what happens when you have a "gully washer" of a rain? Where does the water go? What keeps it from running into their backyard?

Kim

 

[Bama Rambler]

My bet is that those walls are sheet piles with the stone facade.

 

[JJ_Tex]

So........what happens when you have a "gully washer" of a rain? Where does the water go? What keeps it from running into their backyard?

Kim

The yard slopes to carry water to the side yards, where there are drains that carry the water to the street/storm drain. Many a "gully washers" without standing water in the yard

 

[kimkats]

sheet piles

I had to look those up! I bet you are right!! Neat stuff right there!

From what he says about the sloping of the yard it looks like the developer did things right!

Kim

 

[Snikwah]

I was checking out your render thinking it sure does look familiar.....then I noticed the username.

He's got his hands full on this one.

 

[JJ_Tex]

I was checking out your render thinking it sure does look familiar.....then I noticed the username.

He's got his hands full on this one.

Shhh...don’t tell him I’m high maintenance, we will let him figure that out in his own ?

 

[Poolmama!]

Shhh...don’t tell him I’m high maintenance, we will let him figure that out in his own ?

Ummmm...look at my profile pic! I told him I need a referral bonus for Snikwah. Actually I just need my punch list finished....