# StormTech LLC



## jmacd (Jul 14, 2009)

I looking at a project that specs a StormTech drainage field 50' x 100' using sc310 chambers. 
Any one done one of these before and what can you tell me? 
Thank you


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## rino1494 (Jan 31, 2006)

I've done many underground infiltration systems, but never with the chambers. Most engineers stay away from them because they are expensive. They are not hard to install and the underground basins are easy to construct.


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## jmacd (Jul 14, 2009)

Rino, thanks for the reply. That's the only thing I do know, they cost a bunch. The chambers alone are close to 20K for the system, added a lot of $ to the job, all for a 25 year storm!:whistling. 
I checked the web site , looks easy to install, the area to be excavated and quantity of material to haul away is about 1000 yards. Then back filled with stone and engineered fill, very expensive.


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## JDavis21835 (Feb 27, 2009)

Be careful when it comes time to place stone over the chambers. They like to shift, and pop apart. Just what you want when you have them all put together.


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## jmacd (Jul 14, 2009)

I was thinking of using my PC150 for backfill, what machine did you use?


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## rino1494 (Jan 31, 2006)

I just did one that was 75' x 360' with 4,000 ton of #1 stone. It was a tight site, only 5' off a fence on one side and 8' off the building on the other. We could only go a little at a time. Built a ramp to back tri-axles down to dump the stone on the geo-tex and casted it over the pipes with the hoe. Worked it in 6 sections. Had to be careful, because the engineer was adament about not driving on the bottom with the trucks are equipment.

You could prolly move the stone around with a track skid loader or a small dozer. Would be cheaper than a hoe.


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## jmacd (Jul 14, 2009)

I will have excavator,skid, or dozer on site so either one. This site isn't to bad. I don't think I added enough in for pricing, I should of quoted more because I guess I am the low bidder. 

Correct me if I wrong but from what I thought I read today is the base is compacted, fabric, and then 12" of stone and compacted then you build the system. You can use a roller for the base but not the back fill. 

The site package is about 26000 sq/ft of new parking and about 1200 ft of new granite curb and 8 new catch basins. I will post when I see the contract.


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## rino1494 (Jan 31, 2006)

Why would you want to compact the base. The point is for the water to infiltrate into the ground. The engineer designs the system based on infiltration rates of the soil. The backfill should be compacted since there will be a parking lot above it.


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## jmacd (Jul 14, 2009)

Rino, I thought the same thing but the spec on the plan says:

"foundation shall be placed in 6" lifts and compacted with at least two perpendicular passes of a vibratory roller with full dynamic force."


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## rino1494 (Jan 31, 2006)

jmacd said:


> Rino, I thought the same thing but the spec on the plan says:
> 
> "foundation shall be placed in 6" lifts and compacted with at least two perpendicular passes of a vibratory roller with full dynamic force."


Are you talking about the 2B that you place on the bottom ??

Correctly, you should dig it, place fabric down, then 2B, the chambers, then more stone. I believe they want the first layer of stone compacted so that the chamber will not settle and shift when weight is applied from above. The water will still drain when clean stone is compacted.


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## Upchuck (Apr 7, 2009)

I agree w/ rino that the stone is what should be compacted. Usually engineers like to see the ground scarified so that it will drain better.

I would double check w/ designer.


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## JDavis21835 (Feb 27, 2009)

Definitions vary from local to local. Im not sure on your stone names, but ours are a little different. We install these systems on a stone called 6A. Which is basically an open graded stone about the size of marbles. Just placing the stone puts it at density, so im not sure why you would spec compaction for it, assuming your stone is similar


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## WC&T (Feb 22, 2010)

Ive built quite a few of these systems here in the great northwest and have made good money in the installation. The panels are pretty expensive (about $270 for a 30"x30"x84" chamber.) but the install is quick.

first set your structures (usually type 2 48" MH's) and lay your system out off them. 
Then dig in your system to proper elevation leaving a ramp to get a dozer in to trim the hole. insure you dont place you soils for your final backfill next to the hole. leave yourself about 15 - 20 feet to work around the hole if possible. try to have room on all four sides since it will make the installation a lot easier.

Next you should have a testing lab come and test the percilation rate of the soils. Even if it is not required in the specs this could generate a really nice CO if the ground does not perk fast enough and you have to go down another 2-4 feet and backfill with import. (This has happened to me multiple times and has generated nice $ in extras).
After testing roll your fabric out in a way that your wont screw up your overlap and your backfill.

use an excavator (200 size at a min.) to place your rock in the excavation from above. have a grade checker in the hole to insure you are getting enough material spread out but don't get craizy about grading with the hoe. 

Once half your material is in the hole, continue throwing material with the hoe and get a bobcat onto your rock to start smoothing and fine grading out the material. It doesn't need to be perfect, you just dont want it high.

STATIC roll the rock only if it is angular after you finish grading. 

next set up a string line from your inflow structure to the end our your first run (it should be your isulator row wrapped in woven geo textile).
roll out your woven geo textile (if needed) for your isolator row. 

Now sling down a pallet of panels out of the way of the first two rows. 
use 2 to 4 guys working ins pairs to move panels down the string line. Panels go together easy but make sure that you have a screw gun and some sheet rock screws to keep the panels together if they try to spring up. Run out your first row complete to the end. dont worry about end panels or the pipe manifold yet.

repeat that step for as many rows that are in the drawings. The panels go extremely fast, you can do a large system with four guys in a few hours.

After the panels are in have one guy cut out the end panels with a saws all and start putting together your manifold to fit your panel rows.

Once the manifold is down get your hoe and start loading your panels with rock. have one or two guys (with earplugs cause its loud) stand on panels as your bring the rock half way up each panel.

once it is loaded install your observation ports.

then place your rock all the way up (usually 6"-12" above the chambers). It is easier if you can reach in from all sides to place rock and grade it out with the hoe. DONT get on the system with less than 12" - 18" of cover and even than i would only get on top with a tracked skid steer

If you cannot reach the whole system from the sides reach as far as you can, place your fabric on top and than your final backfill before moving onto the system. You can hit these systems with rollers once you have about 2' of material over them.

Once you do your first system you learn how quick and easy they are. Probably not the best directions i could give but its hard to put experience on paper sometimes


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## jmacd (Jul 14, 2009)

Thank you for that very detailed "how to". I will save this for a reference.


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## jonrpatrick (Feb 13, 2010)

I'm currently bidding a similar system by Cultec - $74k for just the chambers part of this storm system - not including storm, etc.

I'd recommend you call the corporate office - they can provide a lot of information and answer a lot of questions. Of course, their system is perfect, cost effective, easy to install, and never pops apart when placing it.

But it can still be worth your time. My contact gave me pretty good input on how fast the system can be put together.

JP


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