Drainage Channels

[gtr cook]

Evening all,

I am going to start sorting my drainage tomorrow. I have it all sorted in my head apart from one thing, placement for the drainage channels.

The question is, where is best to place them? Right in front of the garage door or 50cm to 100cm away from the door with the drive sloping away from the door.

The drive will be sloped away from the garage to aid run off on to the lawn, so the channels will be to prevent water building up and entering under the garage door. The channels will be connected to a pipe going to a soak away.

My current plan is to place them 45cm away from the door (the width of one paving slab). Can anyone foresee any potential issues or has any advice?

 

[theoldwizard1]

The best place for drainage is UNDERGROUND ! What you want is called a French drain.

Cut a trench about 0.75-1m deep and at least 1 shovel wid. Lay some 1m wide "landscape cloth" in the trench. Place a small amount of gravel for leveling in the bottom of the trench and then solid (not flexible) PVC drainage pipe. Fold the cloth in and cover with more gravel.

Make sure there is adequate pitch to carry the water away. You will also need some place for the water "to go". Either and existing low area or a "dry well"

 

[kbs2244]

I do not necessarily agree with the need for underground drainage.
It has it's place, but if we are talking about surface water, then what is called a "swale" may be the way to go.
A swale is a wide, shallow edge angle, ditch.
It catches surface water draining downhill and aims it to, or away from. a target.
You will see them a lot in hilly farm country as farmers manage water.

If you can put on up and around your garage they are the low maintainance way to go.
At the most, they may collect some leaves in the fall.
But nothing that a leaf blower cannot take care of.

 

[theoldwizard1]

I do not necessarily agree with the need for underground drainage.
It has it's place, but if we are talking about surface water, then what is called a "swale" may be the way to go.
A swale is a wide, shallow edge angle, ditch.

So a ditch right in front of the door ? Sounds like an accident waiting to happen !

 

[propav8r]

So a ditch right in front of the door ? Sounds like an accident waiting to happen !

Not a ditch, just a very shallow V.

 

[gtr cook]

Thanks for the replies guys.

The product I will use is http://www.wickes.co.uk/Clark-Drain-Polypropylene-Channel+Galvanised-Grate-1000mm/p/158937. It's suitable to drive over. If I am understand kbs2244 it's a similar idea.

I see what you mean with the French drain. The only issue is the drive will be made of paving slabs, leaving no where to go but run off.

Should I put it close to entrance or leave a gap for water to run away from the entrance and be channeled away to an underground soak away. The soak away bit is definitely happening, it just the positioning of the channels.

I am thinking its better to leave, say 50cms between the entrance and the channel, in case the channels become blocked and overflow. Least there's somewhere other than the garage for the water to go.

 

[beakie]

landscape away from the doors, foundation, etc (aka the swale mentioned above)

if you notice a puddle, or build up of water at the bottom of the swale, dig a trench, bury some 4" bigO (pvc with slits cut into it and landscaping sock wrapped around it) and fill the trench back in.

you don't need lots of gravel, you don't need much slope, water will seep into the ground and flow down hill.

 

[theoldwizard1]

Should I put it close to entrance or leave a gap for water to run away from the entrance ... I am thinking its better to leave, say 50cms between the entrance and the channel ...

To get the water to flow into the grate/channel it must be at least 2-3cm below the entrance.

... channeled away to an underground soak away.

I don't understand the term "soak away". Just remember that moving water can will wash away soil and over time you could have a deep rut !


I had a SERIOUS water problem behind my garage. The soil/grade was pitched toward the garage (and could not changed) and when it rained, water flooded under the wall footer (causing it to rot) and into the garage.

Building a system as I described, including pipe the water 10m away to 2mx2mx1.5m dry well, solved my problem.

 

[gtr cook]

Thanks for the input, have a rough layout now after actually placing the parts out. Will definately have a slope away from the door toward the channel.

A soak away is a hole with either rubble or plastic crates, covered over with grass or paving. The drainage pipe leads into this and helps the water soak into the ground without saturating the floor. Mine will be 1 meter by 1 meter and a meter deep, and about 3 meters from the garage.

I should have the pipe work In it's final position tomorrow so will post an update picture to show what I have done.

 

[theoldwizard1]

Over here, a "soak away" is a "dry well". Plastic crates are great for this as long as you will never drive a car over it !

I have a fairly large dry well (filled with 2-3cm crushed rock), but it does overflow with early spring rains or extremely heavy summer rains. I have a small electric pump and I just lower the level 10-20cm below grade and the rest does "soak away" within a few days.

 

[dtt454]

i might be to late to be of any use, but i put trench drains in front of my garage door, and it pipes out back where it goes on down a hill..... it does work.... but i am always cleaning those things out. even with grates with stainless steel screen over it im amazed how much silt collects in there. ill bet i need to clean them out once a month.

in hindsight i would do all the drainage with gentle sloping of the concrete rather than fooling with underground pipes.

 

[gtr cook]

Over here, a "soak away" is a "dry well". Plastic crates are great for this as long as you will never drive a car over it !

I have a fairly large dry well (filled with 2-3cm crushed rock), but it does overflow with early spring rains or extremely heavy summer rains. I have a small electric pump and I just lower the level 10-20cm below grade and the rest does "soak away" within a few days.

Ah cool, so were talking about the same thing. The dry well will be under the lawn so definitely no vehicle traffic.

 

[gtr cook]

i might be to late to be of any use, but i put trench drains in front of my garage door, and it pipes out back where it goes on down a hill..... it does work.... but i am always cleaning those things out. even with grates with stainless steel screen over it im amazed how much silt collects in there. ill bet i need to clean them out once a month.

in hindsight i would do all the drainage with gentle sloping of the concrete rather than fooling with underground pipes.

No, not too late, any advice I can get is welcome. Trying avoid having to dig it back up again if there are any issues.

What do they clog with, leaves or just dirt?

 

[theoldwizard1]

Ah cool, so were talking about the same thing. The dry well will be under the lawn so definitely no vehicle traffic.

I would recommend a pipe coming to the surface in the center of the soak away. You would probably rather have an over flow there than at the other end.

 

[RivennHewn]

I would recommend placing the trench drain in a bed of concrete.

They are designed to be totally supported by concrete, if you plan to drive over them, and they will crack/fail if only supported by dirt.

https://search.yahoo.com/search;_yl...s&toggle=1&cop=mss&ei=UTF-8&fr=yfp-t-901&fp=1

 

[theoldwizard1]

.... but i am always cleaning those things out. even with grates with stainless steel screen over it im amazed how much silt collects in there. ill bet i need to clean them out once a month.

Mine have been installed for 4 years and I have never cleaned them out !

Proper installation will minimize the silt in the pipe. Start with lining the trench with landscape fabric, wide enough to come out of the trench on each side be 1-2' feet. Lay a couple inches of clean gravel in the bottom. This will allow you to adjust the pitch. I used solid, not corrugated, pipe and applied a "sock" over it end to end and then covered it gravel. Finally I folded in the extra landscape cloth and the top soil.

in hindsight i would do all the drainage with gentle sloping of the concrete rather than fooling with underground pipes.

If you have the space, that IS the way to do it.