Please Help with Drainage Plan

[SliderJack]

Hope to get the slab in next week and backfill. My site is near the bottom of a hill so I'd like to deal with water best I can and would appreciate suggestions.

As you can see from the picture I'm high in the back left, low in the front right.

It doesn't happen but two or three times a year, but when it really pours I get a a little stream across my back yard. For that reason I plan to bury a 4" PVC pipe under the apron to give the water coming down the hill a place to go. That will be about the normal path it took before the garage.

I plan to put gutters on the eves, exit out the back of the garage to a 4" pipe that drains away in the back yard.

Should I treat the block below grade before backfill? Product suggestions?

Should I run a black corrugated drainage pipe around the foundation? Back fill with gravel so that it's sloped, lay the pipe and then exit where? Should I run section (1) from back left, to front left and exit front right? another section (2) back left to back right and exit back right? and a final section (3) back right to front right and exit front right?

Anything else I should do?

 

[gregtwojeeps]

You have good ideas already. Just remember the best drainage solution is Mother Nature. Use your excavator to cut natural drainage swales on and around the side of the building where the rain water be will running towards the most. Then, your draining tools/pipes will not get so overloaded as the soaking in/water table rises. good luck. JMO

 

[mizzoutrover]

if you plan on heating the shop you should insulate the slab and install perimeter drainage, looks like you can gravity drain this very easy.

See these links for information on the amount of insulation and drainage details...
https://energycode.pnl.gov/EnergyCodeReqs/?state=Tennessee
http://www.finehomebuilding.com/how-to/departments/building-skills/insulating-a-slab-on-grade.aspx

 

[csp]

x2 on drainage swales. Let them carry the water away from the building before it ever gets close to it.

 

[ishiboo]

Do both. Swales to mindlessly control the water as it runs. Drain tile around the building. The diagram you posted is missing the drain fabric.

Run the gutters into 4" PVC underground (separate from the drain tile) and far away from the building.

Use dimpled foundation membrane around the block (you don't have much so it won't be expensive) to make sure it all makes it to the drain tile.

 

[larry4406]

Here in VA and MD we use filter cloth on all draintile to keep soil fines from contaminating the stone bed. Other than this, I think you are on right track and the swale diversions recommended are spot on.

 

[matt_i]

Was going to recommend the "silt sock" as Larry already did. It helps you 5-10 years down the road.

Im not a huge fan of the "buried underground" gutters. I have this and they seem to have collapsed and I don't know where they go...next year... I would rather run it out on the grass farther out, and detail the interface with the grass so it doesn't become a rodent cave and the end doesn't get crushed either.

Relative to the stream running at your building, I would create a gentle "ridge" to steer this to one side or the other, or part it around the building. As suggested, let mother nature and gravity do the rest. The slopes you create should be ideally gentle enough as to not interfere with mowing.

 

[theoldwizard1]

That picture you have is very good, except I don't like the corrugated flex pipe. It can hold sand. I used perforated DWV PVC with a sock. I also line my ditch with commercial grade landscape cloth. 3/4" stone is also adequate.

I would install at least 1 solid block on the foundation so that the sill is above the floor.

Don't worry about the below grade block, but do put drainage on the 3 high sides.

 

[SliderJack]

Thanks for all the tips! I usually see a black tar like treatment below grade. Is that suggested for slab or just basement type structure? If so, any special product suggestions?

 

[NUTTSGT]

Was going to recommend the "silt sock" as Larry already did. It helps you 5-10 years down the road.

Im not a huge fan of the "buried underground" gutters. I have this and they seem to have collapsed and I don't know where they go...next year... I would rather run it out on the grass farther out, and detail the interface with the grass so it doesn't become a rodent cave and the end doesn't get crushed either.

Relative to the stream running at your building, I would create a gentle "ridge" to steer this to one side or the other, or part it around the building. As suggested, let mother nature and gravity do the rest. The slopes you create should be ideally gentle enough as to not interfere with mowing.

Matt are they collapsed or is it perforated tile with trees near by ?

For the OP, if you run a tile for the gutters, I'm use solid tile otherwise the tree roots will filter in and clog them up.

 

[casmurbax]

When I moved in into my current house 15 years ago one of the first things I did was bury the downspouts. The area around the house is pretty flat and the previous homeowner had a 10 foot downspout extension sticking out in the yard. I used 4in schedule 40 solid pipe for 20 feet then used schedule 40 perf pipe buried in 18 inches of #3 stone(I think) put fabric down over that. The only thing I wish I did was put a pop-up top at the end of the pipe so I could clean it out if need be.

Before I had the driveway repaved I wanted to do something similar with the two downspouts at the garage doors, wanted the water from garage roof off the driveway. After talking with several different people, I used 4in schedule 40 pipe out about 20 feet from the edge of the driveway and ran about 60 feet of infiltrates(leftover from septic installation).

If this setup is good enough for a septic system I would think its good enough for rain water.

First time posting pictures, please excuse me if they do not appear correct.