I've got a concrete slab front porch that is a bit low in the center, enough so that puddles accumulate there when it rains. The puddles by themselves are not a problem. Over time, the areas where the puddles accumulate causes a thin film of dirt/mildew/who knows what else. This spot is not only ugly and a pain to keep clean, but it is very very slick. I fear for the mailman's safety since he has to walk across that part of the porch rain or shine.

I haven't been under the house to check to see if the porch slab is sitting on dirt. The porch is at least 3.5 feet off the ground, so there's room for additional crawlspace. However, I'm no mason, but I can't imagine a slab with that much square-footage being suspended by anything short of some kind of specially engineered structure of some kind. It's old, and there aren't any cracks, so, since I don't know any better I'm going to assume it is a dirt filled situation, for now.

The only solution I can come up with is to install a drain at the lowest point, directing the plumbing towards the front of the porch (shortest distance to run pipe, and hidden by bushes.)

If a drain is the proper/best course of action, is there a way to cut a hole through the slab using something other than a stout hammer drill and masonry chisels? I'm pretty confident I can do it that way, but my primary goal would be to make the drain look like it has always been there. I'm afraid I might chip too much of the surface and have to patch around the finished drain.

What about a hole-saw big enough to cut through the slab? I'm pretty sure that would do the trick, but I'm on a pretty tight budget.

Any tips on installing the pipe correctly without access from underneath would be much appreciated as well.

Thanks,
Jeffrey

 

You're going to have to cut the drain hole larger than needed, and cut a trench in the concrete going toward the front of the porch to install the drain pipe. The concrete used for a patch will almost certainly look different than the old stuff, but it's a small price to pay to avoid a lawsuit.
The easiest method would be to rent a concrete saw to cut it all first, then a rotohammer to break out the pieces. Or just hire it out to a pro for a more professional looking job with fewer headaches. A really good craftsman may be able to closely match the old concrete by artificially "weathering" it.
Another option would be to call a mudjacker (slabjacker) to come out and raise the concrete back to it's original height. Good luck.

 

I think the hole can be done pretty. Use a masonry hole saw (rented with drill) same size or slightly larger than the drain flange. The kind I know of have hunks of carbide brazed to them. This wider hole is just deep enough to seat the drain a bit below surface. Then use impact drill/chisel to bore a smaller rude hole wide enough for the drain body and pipe.

Porch 3-1/2 feet off the ground. Surely you can figure out how that's supported. What's around it blocking the view?

If it's on piers or such then easily run a pipe under without trenching through. In fact trenching would cause more problems. If it's raised up 3-1/2 feet on dirt or gravel (?) and the run to drain isn't far I would try to auger horizontally or even pound a pipe under with sledgehammer, to clear the way.

By the sounds of it you'll be draining such a tiny volume that garden hose etc. may be adequate "pipe" to carry off the water.

 

Thanks fellas!

Pecos,
I am the "pro" this is being hired out to. Don't worry though, they know what they're getting into, I've done a lot of work for them, most of which I had never attempted before. Our "arrangement" is that they get the work done for a fraction of the price of the actual professionals, (if I'm lucky, I might get 20 bucks after expenses for this particular project,) and I get to "practice" on their house.

Kobuchi,
Yes, it'll be easy enough to figure out how the porch is supported. It's just that it's not my house and will require another trip to go crawl around under the house. The perimeter of the porch is brick, with no holes to peek through.

I think I like your idea better than Pecos'. As much as I would like to rent a concrete saw and cut stuff up, (yeah, I have a touch of the "Tim 'The Tool Man' Taylor" syndrome), the only local rental locations I have access to make you buy a brand new 14" diamond blade from them, even if you already had one...

I hope they don't do the same thing with their drills/masonry hole saws.

As long as I can make a smooth cut to place the drain flush with the surface of the concrete, I can deal with the rest with a bit of sweat and elbow grease.

Still assuming I don't have access from underneath, do you guys know if any pvc fittings exist that will join two pieces of pipe at a 90 degree angle that wouldn't require me to auger a horizontal hole 3 times the diameter of the pipe? A piece of pipe is easy to stick in there, add a standard elbow fitting and it's not so fun anymore. I could make my own fitting, but I don't want any additional moisture getting under the slab if I can help it.

Thanks for the help!
Jeffrey

 

Yay for me and my talent for keen observation! I stopped by the house to see if it was accessible from underneath. I didn't even get out of my vehicle and had my answer: from just about anywhere in the front yard there is an unobstructed view of a standard sized crawlspace vent.

I looked around just to be sure, and what do I find? The crawlspace door is located on the side of the porch! Not only did I pressure wash the whole house, I painted the railing of the porch, and even did some landscaping around it last year. Somehow I missed this big white door on the side of the porch...

It's times like these that remind me why I carry around a small digital camera.

I just thought that was funny and wanted to share.

Jeffrey

 

Cool. So I guess your pipe will hang in the crawlspace under porch. Easy!

 

Wow, I was way off in how I pictured your job. I'm glad it worked out for you!

 

Yeah, the only thing left for me to do is decide how to cut the hole. I'm pretty sure I'll be renting a drill with a hole-saw big enough for the drain flange, then only using that setup to cut just deep enough into the surface to set the drain cover a little bit lower than flush. The rest of the hole doesn't have to be pretty.

But, I've got a couple more questions that maybe you guys can help me with.

Since this porch slab is suspended, will cutting a hole somewhere near the center weaken it, or give cause for concern? If so, I might need to tell the owner that it would be a good idea to get a pro in to fix the problem without a drain rather than risk cracking.

I've recently purchased a RZ spiral saw. They have a tile bit designed for cutting floor tile (usually much tougher to mess with than wall tile), granite (for counter tops, etc.), and a few other hard materials. The bit is about $40, but that would be about what I would spend renting a drill with a hole saw. With a circle cutting jig/attachment, I could cut a very neat depression to set the drain. Given the materials the bit was designed to cut, do you think it would have any trouble cutting 1/4" deep (max) into concrete? For my $, I'd like to walk away having added something to my toolbox, but I don't want to buy the bit and end up having to rent the drill/hole saw too.

I really appreciate y'alls help. Sorry if I ask so many questions about minute details... feel free to tell me to "shut it" when it gets annoying, it won't hurt my feelings. This forum allows me access to the kind of information I would happily pay for if I could afford to, so I hope you'll forgive my "kid in a candy store" mentality.

Thanks again,

Jeffrey