Within the last year, I have purchased an 80+ year-old house. The house has a sealed blacktop driveway that runs parallel to the house. The house has an integrated garage with swing-open (horizontally opening) doors. The garage floor is about 2-3 inches lower than the driveway, with the bottom of the doors being below the drop-off where the driveway meets the garage floor.

The garage gets some water in it, and when it storms it gets a lot of water. For the first time, we realized that the water may possibly be coming in through this gap since there's nothing to stop it (as opposed to general foundation leaking).

Is there a barrier method we can employ on the outside of the garage? Installing a french drain or similar mechanism would be extremely difficult due to the placement of the driveway and the garage, but laying those water-inflatable barriers would not be an option for freezing temperatures. How would I build such a barrier, and of what material? I'd like to keep the profile of the barrier as low as effectively possible to be able to use the garage from time to time.

  • I've seen some sort of narrow metal gutters (maybe 4" to 6" wide) installed as a drain with a metal grate just before the garage ... but those were in places that didn't get hard freezes. – Joe Mar 26 '11 at 2:57
  • A grated drain would be ideal in an area with no freezing weather. Unfortunately, not an option for San Jacinto. – shirlock homes Mar 28 '11 at 10:43

Strangely enough, I have had to deal with this same problem a few times. Short of raising the garage or pouring a second higher floor, the solution is in the driveway. We had to excavate apx 6 feet of asphalt and create a gradual dip draining away from the house and garage to exit water. Obviously, they screwed up big time when the driveway was installed. Installing drains in the garage won't work, especially in freezing, thawing etc. All you will get is an ice covered floor. The only solution is to stop the water from getting in. That is going to mean reforming the driveway to self drain away, not into you garage. There is no quick cheap solution to your problem. Gravity rules!

  • I was afraid you'd say this. There isn't a lot of room to work with outside the garage, and it's a shared driveway. Thanks for your insight. – San Jacinto Mar 25 '11 at 11:55

Create a trough to a sump hole and put in a sump pump. It won't keep the water out, per Se, but will manage it so it doesn't get any farther than the entrance.


since you already have a 2-3 drop-off, take advantage of that and install a french drain inside the garage, but on top of the garage floor.

  • Seems like this might work, especially if my only other option is a serious rework of the driveway. – AWMoore Mar 24 '11 at 22:15
  • 6
    look up a french drain. how are you going to install an in ground drain above the floor? I wanna see this plan. – shirlock homes Mar 24 '11 at 22:42
  • @shirlock a french drain wouldn't work, but they might be able to put in some sort of trough right at the door to take the water ... but giving it the proper slope w/out cutting into the floor of the garage is going to be tricky if there isn't already a slope to the doorway. – Joe Sep 25 '11 at 19:14

I had the same problem with rain water coming into a garage floor. I used silicone spill guards about 1/2 inch high with a silicone base and glued them to the floor with silicone adhesive. It redirected the rain enough that it no longer spills into my garage. An inexpensive way to do it yourself and save money.


The right answer all depends on the local slope of the area. For example you could get some blacktop mix and lay a 3 inch high speedbump of asphalt just in front of the door, draining to.... somewhere else.

Or a channel drain:

Channel drain

Very helpful to get a good answer is to make an elevation drawing, showing the side view of the property and what slope there is. You you can use a water level for this, or a laser pointer and a bubble level.

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