Drainage PVC (4") Under Driveway

[dieselscout80]

I need to run some 4" thin wall drainage PVC under our driveway which is paved.

I am going to dig a trench for it say about 8" deep and then patch the pavement.

My question is does it need support to protect it from crushing?

My ideas if it needs protection is to run it through some 6" PVC pipe or pour vertical sides in the trench to keep it from collapsing?

Is there a better way it protect it?

 

[3Ts]

I have 6" thinwall under my driveway with only a half inch of dirt on top of it, then the driveway concrete of 6". Pipe was laid before the pour so it's tied into the rest of the slab. As long as you're looking at cars and light trucks I'd be sure the pipe had a good supporting bed (sand would work) about half way up the pipe and then fill the rest with concrete. That will give you about 4" concrete over the pipe and should work for light vehicles.

 

[ponytug]

Yes, it needs protection, and I would start by using SCH40 pipe or better, and I would try to bury it deeper if possible. If not, I would pour a wider strip reinforced concrete above it.

 

[garry1p]

Is there a reason not to use SCH 40 instead of thin wall?

 

[4570Man]

Make sure you don’t use the foam core. That stuff is trash. You could just about drive a truck across the schedule 40 solid wall with it laying on top of the ground. You won’t have any problems with that crushing unless you’re going across it with dump trucks in soft water. You might not like the price of 6” pvc though. It’s probably cheaper to use a 12” double wall culvert.

 

[Midniteoyl]

I need to run some 4" thin wall drainage PVC under our driveway which is paved.

I am going to dig a trench for it say about 8" deep and then patch the pavement.

My question is does it need support to protect it from crushing?

My ideas if it needs protection is to run it through some 6" PVC pipe or pour vertical sides in the trench to keep it from collapsing?

Is there a better way it protect it?

The pipe from my septic tank to the leach field runs under the gravel parking pad and is 4" green 3034 (thin wall) inside 6" Sch40 with 6"-8" of gravel on top and has held up for 20ys so far.

 

[4570Man]

The pipe from my septic tank to the leach field runs under the gravel parking pad and is 4" green 3034 (thin wall) inside 6" Sch40 with 6"-8" of gravel on top and has held up for 20ys so far.

The green stuff is schedule 35 and it’s pretty durable. I’d way rather have the schedule 35 green stuff over schedule 40 foam core. They make schedule 20 drain pvc and it’s pretty flimsy.

 

[dieselscout80]

If I ended the 4" french drainpipe at our driveway and dug a trench (18" wide by 18" deep) through the driveway that I filled with packed 57 stone and then repaved the trench since there is close to 12" of fall across that 20'. This would eliminate the chance of the 4" PVA collapsing.

I wonder if that would handle the drainage from the french drain long-term?

 

[woody]

Have you got pictures of the project? I don't use thin wall for anything sch 40 or better.

 

[dieselscout80]

Have you got pictures of the project? I don't use thin wall for anything sch 40 or better.

Not good pictures, but the drain will run under the four windows.

The last two pictures show the slope across the driveway.

 

[ponytug]

Which four windows?

I always use sand around pipes to prevent rock induced cracks. It also helps the next person by giving them a sand layer warning on a pipe.

All the best,

Peter

 

[dieselscout80]

Which four windows?

I always use sand around pipes to prevent rock induced cracks. It also helps the next person by giving them a sand layer warning on a pipe.

All the best,

Peter

Both pictures I attached are the same set of four windows just shown from different angles/perspectives.

 

[dieselscout80]

Digging the trench.

 

[ponytug]

Looks great, and it is nice to see everyone involved in the project!

I think that if you back fill with sand and gravel, and leave the earth where it is, you will have a nice berm to direct surface water away from the building.

All the best,

Peter

 

[dieselscout80]

I got 15 tons of 57 stone delivered today for that.

 

[3Ts]

The rule of thumb out here is 1' of dirt over a culvert and you can drive anything over it. Culverts however are typically corrugated and double wall, but with you being 18" down, you should be fine for most vehicles. (not concrete trucks though)

 

[dieselscout80]

Towed this to fill this because the shop is not done fixing my tractor radiator.

Got 15 tons of 57 stone to go in over the pipe.

However about 15’ of trench caved in the rain/ monsoon last night so lots of hand shoveling vs the excavator work.

 

[dieselscout80]

Success we’ve had two big rainstorms and zero water has come into the garage except a minor amount at the 10’ entrance door (like a quart or less).

 

[newbury]

Thanks for wrapping up the thread.