Driveway Culvert width

Coyote machine · Apr 28, 2015

52' across my 'dirt' drive apron, 2x 20's and 1x 12'. Metal, 12" diameter, wrong size, actually needs to be 18" diameter. Was installed prior to me living here. Access is onto town's dirt road, and the drive has enough width for proper grading at both ends of the culvert, and lawnscape up one side of drive, ditch on lower side to run water to feed end of culvert.

40' will do must drives nicely. 20' is too short for adequate grading, slope at ends, etc. This is a job where bigger is better, and done once, then breath easy.:thumbsup:

joeu235 · Apr 28, 2015

I have a 30ft at the entrance to the property and I can easily turn a 25 ft trailer onto the road.

franklin2 · Apr 28, 2015

Don't know about your location, but here I had to follow Virginia DOT specs for the culvert, including bedding, depth, fill type, drive width, and radius/flare at the street. They pretty much set the specs and it's not up to me to decide. In this case, the street is still in the process of being turned over from the private developer to the county/VDOT, so everything has to pass inspection (the developer has failed twice, for stuff as simple as tire ruts on the shoulder from someone who did a U-turn).

Yep, I live in Va too. When I put a culvert in the first thing I had to do was get approval for were I wanted it to come out on the main road. After they approved that they told me how wide it should be and what size pipe to buy.

Fossil Farm · Apr 28, 2015

If there is a structure on the property, the fire department likes to have at least a 30 foot culvert so they can get their tankers and engines in safely. Ours is 40 foot. No sense cutting a 20 foot section in half. Might as well use it. Most should last decades.

Will_C · Apr 28, 2015

It's one of those things that for a little additional cost up front, you'll never regret.

Will

HarryN · Apr 28, 2015

YES..... you want 40 feet!

heppeone · May 10, 2015

40' at least for sure, 60' even better. Plus, if your planning on adding a gate, think about putting gate far enough back onto property to allow truck with trailer enough room to pull into driveway without end of trailer sticking out in the road while gate gets unlocked and opened.

Gary Fowler · May 10, 2015

I put in a 12" (minimum size per county) 30 foot culvert prior to building my house and it worked ok even for semi trailers but the ditch was only barely deep enough on the upstream side to get cover. My neighbor upstream has no ditch and neither does the one across the road. They said since we are at the top of the hill, they didn't need one and just filled in the ditch. I just asked to county for permission and they came out, looked and said OK but don't blame us if your yard floods. Well I got dirt trucked in and filled in the ditch, left the culvert buried under the fill. No problems in 5 years of heavy rains.

For most any driveway though 30-40 foot would be my minimum length if the ditch were more than 18" deep.

rjkobbeman · May 12, 2015

The comments about extra length to account for slopes on the side are extremely important. For example: if you have 3 feet sides (3 feet on each side), and you have 3 feet of cover on top of the culverts, the slope will be 45 degrees... which is very steep. At that slope, you will lose cover (gravel). Longer is better.

Figure out how wide you want the lane/drive. Then figure out how much cover on top of the culverts. Then figure out how much slope you want on the sides. From that, you can calculate how much extra you NEED on each side/end.

Too short of culverts become an endless pain in the rear, which in a lot of cases are not easily fixed.