Installing a Trench Drain

[Val Kosmider]

Anyone have any experience installing a trench drain? I am thinking about purchasing one of the polyester drains http://www.trenchdrainsupply.com/proddetail.asp?prod=CPS100-13 to install across the bottom of a downhill sloping drive. The objective is to capture the sheeting water before it launches out into the rear yard and washes away the soil. The excavator will dig the trench, and install the four inch line away from the drain to an area of daylight. What do I need to know about installing the drain? I am thinking a six inch wide drain, 13 feet long, will do the job. End drain or bottom drain? Sloped bottom, or level? Is it set in concrete? Or shored up and edged with concrete? Is there a way to get the water to 'drop' down into the drain, as opposed to having it 'sheet' across the top? If so, how far below the concrete edge of the driveway? Should the drain be tight to the edge of the driveway, or set a few inches beyond? Anything else I should consider? I am in a generally frost free part of the country, so freeze thaw cycles are not an issue.

[Prashun Patel]

Wherever it deposits, you risk washout unless it's deposited into a dry well. That's how I'd have it done.
In fact, I'd perforate the drain after it gets 15-20 feet from the house, and drywell from there.

[Kevin Bourque]

$400+ dollars for 13 feet of drain??? That sounds really expensive.

[Myk Rian]

You're lucky to not have a freeze. Ours is in the garage apron, and has heaved because water leaked through and froze under it. I'm considering tearing it out and building an apron with a shallow trench formed in it.
It runs off the side of the garage where the roof drain also connects underground. I have de-icing cable run through it to the discharge in the back yard. The cable works well in the winter, keeping it thawed.
Mine cost significantly more than $400 to install it.

[Brian Philumalee]

Certainly there are better options. I am an engineer for a city and we do not allow them in right-of-way. For good reason, they're a pain to maintain. There is no sump to these and unless you're on top of maintaining them, they will quickly fill up with a mulch-like compost....not to mention, if you decide just to power wash them to the end drain, they will quickly fill up your drywell.

Not sure if you are building a driveway or retrofitting something but if it's all new, design/construct to a single catch basin or a series of small catch basins and discharge to a drywell or drainage swale. Check your local guidelines or code as they will have their requirements.

All that being said, I have put these in when no other option is available. Not sure why you need an excavator...you'll probably make more of a mess than its worth. Some troughs will come with a set slope...1/4" to 1' but others will not. If you can, install to this min. slope, it will be somewhat self-cleaning. Biggest failure on these are the grates...if they are not traffic rated (cast or ductile iron) they will surely break in time with loading. And for that money, you can get H20 rated grates.

Brian

[Clarence Martin]

Got a some similar problem on the back roof . Had to take the gutters off because the heating pipes were installed in the attic , making the attic warm and no matter how much ventilation, pipe wrapping and blown in insulation we put up there, nothing kept the ice from backing up on the roof, so we took the gutters off the back roof. Now, in the Spring, Summer and Fall when it rains, the water comes pouring off the roof and hits the ground. Finished Dry loking the basement wall with 2 heavy coats of dry lock. Held up so far. Went out today to pull the weeds around the side of the house and while I pulled the weeds along the edge of the house in the back when the problem was/ is, I noticed a small section of the three layers of heavy black plastic sheeting that I layed down under the dirt against the house , had not butted up against the trap door, where I have the majority of the leakage coming from. I put a green plastic gutter downspout drainage thingamajig (Don't know what the name of it is:confused: ) and will see if that helps out.

Still would like to try the buried perferated drainpipe installation method that I read about. Just dig a wide enough trench where the water hits the ground from off the roof, throw crushed stone down , line it with 3 layers of heavy black plastic sheeting, put some more stone down, set the pipe on top of that, connect it with a t- connection to the gutter drain pipe, then level it off with either pea stone or crushed stone.

[Fred Perreault]

The precast trench drains can work, but as Brian mentioned the grates are the key. H20 traffic bearing, and easily removable are the best way to go. Occasional cleaning is a must, and setting them across the roadway at a slight angle, downhil, will help capture the water and make the unit somewhat self cleaning. If you pipe the water to the side to an area that has a benign grade, and make a small stone (2"-8" rocks) revetment and a pocket of similar stone for a drywell (18"x18"), it should be servicable providing you maintain it... remove leaves, organic matter and other detritus. If you acquire sturdy preformed trench drain sections, digging them in by hand is not a big deal, but getting the water a distance away is an unknown. If you install the whole deal yourself, make sure to compact the bottom of the trench, and backfill and compact with a dense material. Good luck.

[Val Kosmider]

Thanks for the tips and advice. I think I have most of it covered. $400 is actually pretty low cost for what you get--as compared with prices across a variety of suppliers for drains which are slightly larger. 8" runs about a thousand.... Why the excavator? To do French drains (crushed stone, fabric, perforated pipe, etc.) on either side of the trench drain, and to dig the 150' trench where the run off heads down the hill to daylight in a 'drainage swale'. Yes, I can dig the smaller area for the trench drain myself, if that is all there is. Grates are heavy duty plastic of some sort....or iron/steel for a few more dollars. The drain is off the downhill end of the driveway so it need not be able to support anything like a car. I will go with the sloped version, so the water drains to a bottom drain, which will go down to connect with the drain from the French Drains on either side, and then on down the hill in two four inch PVC pipes. There is a small complication (isn't there with any job?) where the trench drain will extend across a laid stone path. Still, I will try to set the trench drain in a concrete footing, and do a concrete surround in an effort to get the water to 'drop' into the drain. Otherwise, if you leave it at ground level, the water sheets across the top and you lose some to the downhill side.