Wednesday, March 12, 2014

drain-pipe-under-driveway



I need to connect some 4 corrugated pipe about 15' under a gravel driveway that gets occasional use (path to backyard) by my truck and rarely a skidsteer when I need to rent one. At Lowe's I see a thin white PVC drain pipe that says 1500 lbs crush on it ($10). They also carry one that's green with flare at one end ($20) but says nothing about crush. The last choice is schedule 40 PVC which seems to be the most substantial but also says nothing about crush.
Which is the best bet? It can be buried only an inch or two deep then will be surfaced with gravel.
Also, connect PVC to the corrugated?

My understanding is the SDR-35 (the green pipe) would be the way to go. It will handle under-driveway stresses much better than the white drain pipe. It attaches just with the flare end and has a rubber gasket.
I'd try to get it a bit deeper though if possible. 1-2 doesn't give it much protection. You may find yourself having to replace it after a couple years (which might not be too horrible if necessary).
You should be able to get a PVC adapter to go from 4 black corrugated to 4 PVC. I'd imagine you could use standard PVC cement on the SDR, but I'm not certain.

I also reside in S. FL.
I prefer corrugated (HDPE) polyethylene, dual wall drainage pipe (a/k/a as ADS/Hancor dual wall/N-12 pipe) in a situation similar to what you describe. Unlike the single wall corrugated pipe carried by the big box stores, the dual wall would be significantly more crush resistant but I don’t know the ratings. You’ll find dual wall drainage pipe at irrigation suppliers, especially if they also specialize in drainage pipe related supplies. In 2006, I paid $20.82 for Hancor dual wall/N-12 4 X 20'; 4” snap end caps were $2.95/ea. This is based on wholesale pricing.
I can’t visualize what your doing when stating the top of pipe cannot be buried more than 1” or 2” below ground, and that your connecting pipe is 15’ under the driveway (or did you mean inches?). I have several 8” and 12” pipes buried deeper in swales that allow tractor trailer trucks and heavy equipment to drive over them. In one situation where depth was limited, I used a technique of installing two smaller diameter pipes side-by-side rather one large diameter 2X in size. One issue is your concern about the pipe being crushed. The other issue is that weight of a vehicle can cause the pipe to lift on one side if both wheels don’t contact the pipe simultaneously. A related issue is that the pipe initially wants to float upward during heavy rains although that has only been a temporary problem for me until settling in. Remember, during our wet season the ground can become saturated although may be you would not be driving over your pipe in that type condition. If you could get the pipe down a few inches more, I would be more comfortable saying you should be okay . . . your vehicles are light but have you thought about whether something like a loaded dump truck or other heavy equipment might need to get into your back yard?. I would stay away from the thin wall PVC irrespective of it saying “1500 lbs crush . . . I would at least want to see mfg. paperwork making that claim and would be skeptical if Lowe’s personnel have a hand made sign over this pipe.

Sorry - the pipe will run under the drive for a distance of 15' (the drive is 15' wide). Depth of the pipe has to be very shallow to maintain some slope between the drain grate in front of my detached garage (unfortunately just slightly above grade) and the pipe leading out of the yard to the swale. Florida - not really much elevation to work with!
1500# is printed on the thin-wall pipe with the other specs, not info from staff. Actually I think the Schedule 40 said 4400# but it didn't say crush so I have no idea what it means.
So the consensus is either the green or the dual wall corrugagted I think (which I've never seen anywhere)? Nobody recommends Schedule 40 (thick-walled PVC) for this?






Tags: drain, pipe, under, driveway, dual wall, drainage pipe, about crush, corrugated pipe, dual wall drainage, dual wall drainage pipe