Trench Drain for RV Garage Driveway

[akadeadeye]

We are building a garage for our MH and have found the need to install a trench drain in front of the garage to handle some water run-off from the driveway sloping toward the garage. This is to avoid excessive slope we would need if we didn't do the trench drain. The slope could cause clearance problems either at the front and/or the rear of the coach.

Question. What load rating or type of trench drain do we need? Our back axle weighs about 19,000 lbs. and the front axle weighs about 12,600 lbs. Does anyone have any experience with this? Thanks for your response.

Don

[desertdeals69]

Is the garage already built or still in planning stages? If not built I would raise the foundation so the driveway would be more level. I have a little hump at the beginning of my driveway to keep the water that comes down the street from coming in the driveway. My driveway is 30 ft wide and 55 ft long and my garage is 32x64 ft with a 14 ft high door and 15 ft interior. If you can't raise the foundation maybe you could slope the driveway down at the beginning and slope it up as it enters the garage.

[Briarhopper]

Installed some trench drains in the distant past. Can't remember the particulars, but I think you just need a trench drain designed for use in a traffic bearing situation. Might could be simply a concrete trench with a lip for a cast iron grate or a store bought like one of these: http://www.zurn.com/Pages/ProductsList.aspx?NodeKey=387874.

I believe it would require some calculations to determine the correct size based on the expected water flow.

[dickandlois]

Hi Don,

San Antonio-- one of our stops when in Texas.

Kind of hard to say with out some grade information and maybe you could attach some pictures of the sides of the driveway and notes regarding your clearance concerns.

Also, information on your thoughts as to where you would discharge the water from the trench and the area around it.

Rich.

[akadeadeye]

Thanks for the replies. Yes, the garage is built and prior calculations by our contractor indicated there would be enough clearance. But we are short about 2 inches from the trailer hitch clearing the garage slab. I have attached a picture. I know, not good planning but I didn't think this would be a problem and trusted those who agreed.

Don

[Briarhopper]

How about a small hump in the driveway strategically located to divert water and lift the coach to clear the hitch??

[wolfe10]

Don,

Perhaps I am not seeing the proper perspective from the photo, but it looks like your drive slopes away from the garage, so likely no "water into garage" issue.

It also appears that you have plenty of height in the building, just not the door. Have you explored installing a taller door?

Brett

[akadeadeye]

Don,

Perhaps I am not seeing the proper perspective from the photo, but it looks like your drive slopes away from the garage, so likely no "water into garage" issue.

It also appears that you have plenty of height in the building, just not the door. Have you explored installing a taller door?

Brett

Brett, the door is high enough. 14 feet. We are 12' 10". The issue is that with the current slope down from the garage apron to a low point before it starts sloping up again to the house the rear bottoms out on the garage door apron. They are exploring moving the low drainage point from where it is now (about 1 1/2 ft. behind the rear wheels as shown in the photo) to about 1 1/2 ft. in front of the rear wheels so that I bottom out and then start climbing toward the garage door opening. I am thinking we can eliminate most of the slope down from the garage door by installing a trench drain, thereby having more of a leveling effect instead of a low point dip. Depending on where that low point dip is, without a trench drain I am concerned that while we have have solved the trailer hitch/rear end issue, we may create a front bumper issue. Or, I may just not be seeing it like others. That is the input I need. Thank you for your reply. There is a better side view photo I could supply but it is over the limit in size for this forum.

Don

[wolfe10]

Don,

Yes, I see what you mean. Moving the low point further from the garage should solve the hitch issue, as the rear wheels would be headed "up hill" before the hitch gets to the garage itself.

[akadeadeye]

Don,

Yes, I see what you mean. Moving the low point further from the garage should solve the hitch issue, as the rear wheels would be headed "up hill" before the hitch gets to the garage itself.

Brett,

With that in mind, does it matter that everything will be 5 inches higher when the concrete is poured, or does the same problem follow the elevation? Right now the hitch receiver is about 2 inches below the garage floor level as shown in the photo. Do I gain 5 inches after the pour or does the same problem just shift upward?

Don

[wolfe10]

Don,

Makes sense to me that if the grade remains the same, and everything is raised 5" you would clear.

Where is a civil engineer when you need one?

BUT, I would not pour a drive assuming that the next RV would have the same or more rear clearance.

[dickandlois]

Don, Some good point's from Brett. Brett we have one in the family, but currently serving Uncle Sam.

Thanks for the picture, worth a thousand words.

The height looks good regarding the top of the coach, I'm seeing a lip in the picture where the garage door sits above the driveway.

This is the point where the hitch contacts the floor level, or I'm looking at things wrong. When you mention raising the floor 5in.

Is that added to the current lip?

That being the case then point or the distance to where the front of the coach would bottom out would need to be well into the

dip or drain in the driveway.

This would allow clearance for the front and raise the back of the coach thus clearing the hitch.

NOW, with that action one would need to have the garage door height, when open high enough too clear the rear roof line and AC unit; until the coach front wheels start there rise out of the trench area. That will slowly rotate the roof away from the door.

Hope I'm looking at things properly.

Rich.

[hermanmullins]

From my point of view I would drive the coach in rather then backing it in.

Herman

[akadeadeye]

Thanks to all for the replies. Met with builder and engineer today and the problem is solved. Will install a trench drain with heavy metal grates which will allow the clearance to come up 3 inches from 1 inch which is fine.

Herman, that would be easier but I have a sewer dump installed and water and electrical hookup on the driver side in the garage so backing in is my only option if I want to use the "facilities".

Don

[hermanmullins]

I understand. But could you just run the sewer hose, water and electric under your coach?

Herman

[jfxg48]

Brett,

With that in mind, does it matter that everything will be 5 inches higher when the concrete is poured, or does the same problem follow the elevation? Right now the hitch receiver is about 2 inches below the garage floor level as shown in the photo. Do I gain 5 inches after the pour or does the same problem just shift upward?

Don

Just saw this today, and that was my first thought, too, when I saw the photo... they've not even finished the pour! Looks to me like all will be fine when the driveway's complete. The garage slab is already at finished grade, and should be sloping outward. I don't even see a drainage issue. Temporary ramps or fill should do the trick until the final pour. You can probably eliminate the low spot with the pour as well, if so desired. Am I missing something?

[turtlemechanic]

I was wondering the same since it's not finished, just thought it was obvious that the "step" would be gone after they pour, and then the hitch will be 5 inches higher