Need advice for driveway repair/sloping/drainage

[mrennie]

Hi Guys:

This is a long story so bear with me!!!!

I'm a bit out of my element here (alot actually), and am looking for some advice.

Background:

Bought a house in 1997, it is a bungalow with an attached garage and carport.

I have attached some recent pics to help explain what my issue is.

 

[JB4310]

If you're not gonna pave it and want to just fix it up.

I can see the slope towards the garage, but I can also see by the concrete floor of the garage that there is slope away from the house across the front of the garage. That's what you want to prevent ponding in front of the garage.

It looks like there's some grade away from the garage out to where the front tire is, looks like it was designed like that, like there is a slight swale there going across the driveway away from the house. If that's true, that's what you want, you may have to clean up that swale to allow the water to flow off better if it's puddling now. just scrape down any high spot that's holding water behind it, with a steel rake or shovel, if it's super compacted you might need to use a pick to loosen it.

That's what I see in the picture, doesn't look all that bad. If you were gonna pave it you would want that same profile.

JB.

 

[mrennie]

So the first spring after we moved in we had problems with snow melt runoff and early spring rains coming into the mudroom/garage since it was almost flush with the driveway grade, which at that time had a mild slope TOWARDS the house/garage.

The obvious problem is that the garage/mudroom was built too low and there was no easy way to regrade the driveway to have water slope away from the garage. I believe that if they had built it 10" or 1 block higher all would be good but it is what it is

The entire area is dense clay and we experience significant frost depth in the winter as the temps drop to -40C/F at the extreme end....it is not uncommon for frost to go 5-6' feet deep where the snow cover is thin. Constant plowing of my driveway and parking the car/truck only makes it worse.

So, not knowing anything about landscaping or drainage, about 8 years ago I hired a local company to fix this. They explained to me that because the garage was built too low they could not dig the driveway down enough to create a continuous slope away from the house for very far as the road I live on is at least 1' higher than the garage. Compounding this is that the phone/hydro services cross the driveway at an angle are not very deep.

Their solution was to dig out several loads of clay and create a gentle "swail" or trough that sloped away from the garage about 8-10', and that also sloped towards the carport which leads to the lowest spot in my yard and out to a field.

Because they were concerned about the frost being driven down into the clay by our vehicles, they added 2" foam insulation on top of the clay from the house outwards 12' and from the entrance door to just past the first garage door. On top of the insulation they added some gravel mix and then geotextile cloth, then 4" of gravel over that. Finally, they added 2" of "chip dust" or find crushed rock.

This all seemed to make sense at the time and everything was good throughout that first summer, with no further issues from heavy rains since the water would run away from the garage then down the swail towards the carport & field.

However, the next spring we had even worse water entry as soon as the snow started to melt. The reason was because while the insulation they installed certainly did limit the frost penetration and amount of heaving directly below, the result was that the rest of the drivway still heaved at least 6-8" and all water now ran to the lowest spot which was right in front of the garage entrance door!! The swail did nothing at this point and this small pool of water now sits there until late April. The contractor had agreed to come back and repair any issue that arose (and in hindsight I am an idiot for taking his word and not getting something in writing), and when I informed him of the issue he basically stopped returning my calls and wouldn't do anything about it.

Last year I bought myself a B26 and as a temporary fix I removed as much of the gravel as I could from the area that is not insulated, which is almost low enough to allow the pool of water near the door to drain off when the frost has heaved the driveway, but still not enough. I have also hit the geotextile cloth and clay and now there is a mess of mud and it looks like crap!!

 

[mrennie]

So what I want to do is repair/modify the area all along the front of the garage and carport (56' wide) as well as far enough away out from the garage (24') so that when we park our vehicles in the winter there is minimal change to the slope compared to the summer. Basically I want a year round solution.

Note that rest of the driveway is OK and I don't care if it heaves as long as the water does not run towards the house and pool anywhere.

If you look closely at the pics from today you'll see a slight swale or trough that also slopes towards the carport. It currently is close to what the final grading should look like except I am down to the clay in front of the carport and when I back the tractor under it when the ground is wet I am creating ruts and the water stops flowing down the swale.

My initial plan is:

-dig down 12" deep across the garage/carport (56') and out 24' (1344 square feet!!), then add 2" expanded styrene insulation.

-install 4" perforated drainage tile piping around the perimeter as well as a few runs down the middle then bring this out to the field by burying it.

-over the styrofoam/drainage tile I would put 5-6" of road base (whatever that is?), which I would slope with the required swale, then compact with a tamper.

-over that I would put 4" of crusher reject (smaller sharp gravel), then slope with the swale and compact.


My thinking is that any water that runs towards the "protected area" should hit the drainage tile and be carried away. The frost heave should be minimized due to less water, and because the entire front of the garage/carport is insulated, there should be no low spot near the structure.

I started pricing this out and this is $$$!!!

Looking for any advice on if I am out to lunch with this plan, what is overkill, what I have missed, keeping in mind the frost depth up here and the fact that I cannot dig much depper than I currently am because of the hydro/phone cables.

Thanks in advance

Michael

 

[mrennie]

Hi JB

Thanks for the quick reply. I agree with you 100% except I need to take into account the frost heaving (I was still typing my diatribe when you posted).

Glad to hear what you would suggest taking that into account.

 

[Scooby074]

Not a good situitation for sure.

What id probably do would be V it out. With the street one tip of the V and the garage the other.

Then id put a crock (catch basin) in the valley formed by the V. T the water collected there would be directed away from the drive.

Id probably dig down through as several inches of clay and replace with good rock. Keeping the geotex if possible. More rock the better to prevent heaving. Heavy rock like rip-rap several inches thick at the bottom. Then some stone.. Top with crusher run if you want a concrete like surface. Your plan looks pretty good so far, but id scrape as much of that clay out and replace with as much rip rap as the budget allows.

Foam is something ive never heard of for a driveway. Where are you at?

One last thing as insurance would be a trench drain across the front of the garage to catch any runoff . This might be overkill... but....

EDIT: do you know where your cables are? Have them located. Then work around them The V doesnt have to be in the centre of your drive. work around your cables. Id just try to get the water to a centre collection point. You could even have a shallow slope over the cable section if you had to. Worse case scenario youll have to get hydro out to move your service....Dont want that $$$

 

[JB4310]

First of all I do alot of drainage work, not so much with gravel driveways as mostly paved around here.

I can see the obvious spring summer and fall problems, but that extreme winter heaving has me a little stumped. And I have never heard of putting insulation under the surface of the driveway, It most be common where you are but I never even heard of it. So take any advice from me with a grain of salt, what ever that means

Looking at your plan I would say yes you need to remove that clay that is expanding so much when frozen. but I'm guessing 12" may not be enough.
I THINK you might be able to do away with the insulation if you went deeper removing the clay, at least 2 feet. I know it's alot more work, but if you can put it on your own property you could save a little there. You may even get away without that drainage matrix under the driveway, though I'm all for drainage systems. Maybe shape the clay when you get down as far as you are going to a swale just about where it is now and run a perforated pipe across the driveway at that point. The first 8 inches on top of the clay would be a uniform sized aggregate like 1 inch. the shaped clay to the low point and the loose stone would allow water to flow towards that drain line at the lowest point.

We would normally look closer at the point of last defence and try to install an all season drainage system across the front of the garage/mudroom.
You mentioned bringing the pipe out back to discharge, it would need to exit to daylight, if your winters are as bad as you say I imagine there is not alot of daylight near the surface of the ground out there in the winter?
So that brings up other challenges making sure the end of the pipe isn't frozen when you need it.

Again, these thoughts are not based on local experience, so be skeptical.

JB

 

[dstig1]

The obvious problem is that the garage/mudroom was built too low and there was no easy way to regrade the driveway to have water slope away from the garage. I believe that if they had built it 10" or 1 block higher all would be good but it is what it is

I think you may have the best solution right here. Raise the house up. Heck, add 1 or 2 courses of block, insulate like the rest of it, and then you can regrade your driveway as desired with fill. Get some quotes from house movers, and you may be surprised how cheap it will be to do. Otherwise you are running into too many constraints in trying to fit the ground to the house elevation.

 

[inveresk]

First thing I'd try is a linear drain across the width of the threshold, connected into the surface water drainage system.

http://www.acousa.com/drain/index.htm

 

[mrennie]

Good info, keep it coming!

I forgot to include that I did already add a weeping tile along the garage just below the surface as a "last resort" several years ago and it has been saving us from having tons of water coming in, but it does not solve the problem of heaving around the insulated section and the "bowl" that develops from February to May is part of the puzzle I am trying to solve. Ultimately, I want no water coming up to the garage at all but will still include a pipe along the wall for added insurance.