How steep is too steep?

[Truett Neathery]

Does anyone know what pavers (asphalt) consider the maximim grade for driveways before a concrete driveway needs to be used? How do they determine? Seems like a concrete driveway would run downhill before it set up. Is there any "Standard" for this?

 

[Restrain]

I've seen some veerrryyy steep concrete drives, and anyone in the mountains have seen paved roads that you wonder how goats go up them.

The bottom line is that you can pave almost anything. For that matter, you can pre-pour concrete slabs and set them in place. Asphalt has a very high viscosity and just doesn't run downhill when put in place. So, my rule of thumb, is if you drag your bumper going down to the street, it's too steep.

 

[Terrel L. Shields]

Seems like a concrete driveway would run downhill before it set up.

It does, but they use a thick mix and wire mesh to hold it in place. Asphalt would lay about as easy but the rollers have to be very careful going downhill. Up hill tends to be better and again, they need a good base to stick to for maximum quality.
I hate steep driveways and would never buy a house with one.

 

[VolcanoLvr]

I'm thinking 90 degrees might be the upper limit for either!


I have a friend in Placerville on Seeforever Court. Any chance you've been out that way?

 

[Fred]

I'm thinking 90 degrees might be the upper limit for either!

I think it's less?

Once you can't find a contractor to guarantee the work, you have probably crossed at least one important threshhold.

 

[Bill_FL]

Bristol Motor Speedway has 36 degree banks. The surface was changed over to concrete several years ago. 36 degrees is VERY steep. When they wanted it to go concrete, they had a hard time finding anyone who would pour it. They did find a contractor who basically invented a new way to pour it that made it stay. From what I understand, it is very expensive to get it poured on that kind of an angle.

 

[Fred]

36 degrees is VERY steep

Even for a mountain goat.

Bill's point implies a second threshold: cost. Even if you can find one contractor who will guarantee the work, you can get to where the cost of creating access wipes out so much of the with-access value, that the as-is value gets too close to zero or passes it on the way down.

 

[Todd Ruhl]

I just spoke with a friend in the asphalt paving business. He said they start getting nervous when the grade approaches 30 degrees. The problem is the limitations of the equipment: dump truck, paver, vibration machines, roller, etc. On the other hand, concrete can be applied vertically. Google "Shotcrete" or "Gunite". As Steven pointed out, these specialized concrete applications are far more expensive than traditional pouring. Generally speaking, the steeper the grade, the steeper the price.

 

[Bill_FL]

Todd, gunite and shotcrete style can be used vertically, for pools and such, but I dont think it has the strength to be driven on. Asphalt can be done very steep. Daytona and Talledega speedways are in the 32-33 degree range and they asphalt. Bristol was asphalt before the ripped it up to go concrete. Infact, Bristol was "repaved" last year adding new contours to the banking to make it a progressive type banking. All in concrete. If you can write the check, they can do about anything.

 

[Mr Rex]

Someone else mentioned precast slabs. That's what they use on boat ramps, pouring concrete underwater makes it a tad difficult to maintain the proper cement/water ratio.