Garage Floor

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Posted by: from Oakville
7/9/2012 at 3:31:53 PM

We have an attached garage which we are currently renovating. Have a problem with water pooling - because the original concrete floor dips up to 5 inches from the garage door.

The floor is in good condition - no cracks and fairly clean - but every spring and when we have a heavy rain - we have a pool of water in the garage that comes in under the door.

We have replaced the door seal and will be buying a new door - but know from experience this will not correct the problem with the original construction.

Someone recommended building a concrete "speed bump" behind the garage door to direct the water back out. Someone else recommended installing a "trench drain" - and letting the water just sink under the garage floor - not my favourite idea.

Have no idea what is under the garage floor and we live in a heavy clay area.


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Date/Time7/9/2012 at 3:39:07 PM

Hi Susan,

I am not sure if the water comes in from under the door or the sides don't have a good seal. You can adjust the door to close higher and build a small "ramp" under the door the height is depending on how much water you have inside

Can you send me a picture? You can post it here.


Harry C.

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Susan in Oakville
Date/Time7/9/2012 at 3:50:51 PM

Hi Harry

We have actually watched the water come in - it comes in from two areas under the door - one is approx in the middle and the other about 3 feet from the side.

I don't have a picture - sorry.


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Date/Time7/9/2012 at 4:25:47 PM

I would recomend the trench drain, with slope away from your house.

Using drainage pipe under ground from the trench drain to what they call a french drain, which is a hole in the ground that is filled with stone to help with drainage. It will be your most pratical way to solve this issue.

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Spencer from All Home Repair in St Thomas
Date/Time7/9/2012 at 4:56:59 PM

I have seen a contractor fix a problem like this.The issue is not so much how the water is getting in but why it is staying in.

You have a low area in the floor. It is probably not much but will always collect water that reaches it even when the door is open and rain blows in.

Repairing this will require some searching on your part. Not all concrete guys will know how to deal with the repair so that it is permanently fixed.

The floor needs to be raised so that it is higher than the outside perimeter but with just a very thin layer. This takes the right product applied the right way so it will look good and stay there.

I suggest talking to some flooring people for information about a specialist that they may have used for this type of problem.

Good luck


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Date/Time7/9/2012 at 7:16:34 PM

Hi Susan!

Well Chris is right to install a trench drain in front of your garage door. However, any snow or water that is on your vehicle will still pool in the center of the floor. Although that should not be that much and if you can live with that then ok.

Otherwise the inside solution would be to install a floor drain which in my eyes should had been installed in the first place.

Check with the building inspectors in your district and see what is code and whether a drain can be tied into the sewer system or can be drained onto your property some wheres.

Hope that helps.


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Date/Time7/9/2012 at 7:29:14 PM

The problem is as you said, the floor is 5" lower than the door. All garage floors are supposed to be sloped towards the door. Any water or snow brought in by your car, will drain out the doors. The seal under the garage door is mostly an air seal, it is not designed to stop water from flowing in.

The trench drain idea is a patch at best and most likely cost more than fixing it properly. Also with the clay it won't drain very well anyway. You need to raise the concrete floor level and have it sloped properly.

Any concrete company will be able to pour a new floor over your existing floor (Especially since it is out of level so much). I'm guessing $2-3K for the job. Don't buy a new door unless you want a new one, it won't fix your problem. The speed bump idea will work, but again is a patch. It won't get ride of the water brought in by your car.

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Date/Time7/9/2012 at 8:31:04 PM

There are two problems. The first is that the garage floor should slope from the rear wall of the garage to the front of the garage or overhead door. There should not be a 5 inch dip in the concrete floor from the front of the garage.

That is not standard construction and there could be a problem with the base of the garage floor. There may not be enough crushed stone base or reinforcing or the settling of the grade or ground. The second is that the exterior grade or driveway should slope or flow away from the front of the garage door.

If the garage floor dips 5 inches then the concrete garage floor needs to be broken up with a new floor poured on a proper base according to the Ontario Building Code with a slope from the rear of the garage to the front and then onto the driveway. The garage floor should not be lower than the grade at the front of the garage.

A trench drain can work as long as the water is directed away from the garage but I am not sure if you have enough slope to move the water. But please do not direct it under the garage floor as that is asking for future problems.

A speed bump may work but I would not recommend it unless I have seen the site conditions. It could be an alternative and your most cost effective solution.

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Paul from Paul's Contracting in Barrie
Date/Time7/10/2012 at 6:46:34 AM

Hi Susan, in addition to what's already been said, try having a look at the exterior grading. Where does the water run outside the garage doors? Is it possible to alter the grade to redirect the waters course? Try looking into an exterior grated strip drain in front of the garage doors installed in the driveway. These can drain into a dry well or French ditch weeper system depending on grades and location.

There are a lot of houses built with driveways that run down hill into the house, which control water and flooding issues with these types of drain systems. Search Google "driveway drainage" for some photo's and examples.

Hope this helps provide another option for you!


Paul Counter


Paul's Contracting

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Date/Time7/11/2012 at 12:15:12 PM

I had the same problem in a previous house. 1- drill holes in the low spot and let the water drain under the slab...or 2- remove the slab and repour it to correct slopes. This is what I did.

Paul Justice

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Henry in Ottawa
Date/Time8/21/2012 at 7:15:12 AM

The level of door is too high from the basement..That's why it is flowing out on the floor through the gap of the door.

To fix this problem either you can pack the door permanently or make a proper slope on the floor so that there would be no problem of water drainage.

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