# Drilling drainage holes at base of patio wall



## tnprogrammer (Apr 16, 2014)

Our house is two years old. The builder built this wall around a portion of the patio. It has a proper grade to it, but water builds up in the corner because no drainage holes were installed. I'd like to drill 2 or 3 holes that empty into the french drain I installed around the outside portion. I build a lot of stuff, but I don't do much with concrete, so I don't want to screw up and damage the patio foundation. What is the best way to drill some angled holes through the wall at the arrows in the pic? The bottom course of block in the wall looks to be filled with either concrete or mortar. I know this because I removed the end cap block for installing the light and could see down in it. I would need to drill down at a bit of an angle, which means drilling through the patio concrete. I just don't want to blow out big pieces of the concrete and damage the patio foundation under the wall.
Thanks.

I would drill from the inside:









The holes would exit below the drainage rock:


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## stadry (Jun 20, 2009)

we'd use a diamond core drill w/water but its not a diy job due to the rqd equip,,, coring from the inside will req a very long drill tube usually not in stock even in a pro's bit locker,,, using a hammer drill will cause a blowout on the end of the drill'd hole ( big jagged-shaped hole )

i'd keep a broom handy & sweep the wtr out of this area were it mine,,, we own the necessary equipment but i'd rather not buy the drill tube for only a 1-time use,,, a pro might have core drill extensions,,, this is a large $ to spend for only 15min work imo


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## ZTMAN (Feb 19, 2015)

Just drilling would not do you any good. I assume there is a block wall that the bricks were adhered to. If you drilled a hole, the water would go in the web of the block unless you piped it. I installed a small trench drain on our patio in a low area, and it works well.


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## tnprogrammer (Apr 16, 2014)

Both of you pretty much confirmed what I was thinking. I figured the hammer drill would blow out the back side. And I'm not about to spend the money for a core bit with extensions for a small one time job like that. I do in fact sweep the water away every time I get a chance when it rains heavy.
ZTMAN, My plan was to knock through a small pvc pipe if the hole could be drilled for exactly the reason you mention. Even if the water flowed into the drilled holes the cinder block would soak up a bunch of it I'm sure. 

One last question...what if the hole could be drilled from both sides with a large diameter hammer drill bit and meet in the middle? That means I'd have to temporarily remove some rock from the back side and maybe dig out a bit so I could get the drill down there, but if it would work I would do it.

Thanks for the input guys.


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## de-nagorg (Feb 23, 2014)

Getting the holes to align when drilling from both side is an exercise in geometric mathematics, are you up to it. 

As stated there are specialized tools needed to core drill this, I worked as a kid for an exploratory mine driller who used a 1 inch core drill to drill into rock walls to extract core samples, he had extensions to add onto the drill itself, We would drill 10 feet at a time, pull out and remove the core from the bit 10 feet at a time. 

If you could find a person with one of these 10 foot bits and the equipment they would be able to do this for you.

I like the other option offered, a trench drain, installed in the area close to the structure, is easier, just need a concrete saw to cut a channel in the floor, and a drain, and piping to run underneath the grass to an outlet far away.


ED


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## Oso954 (Jun 23, 2012)

+1 on the saw cut trench. It will drain the low spots.
Not sure the drain and pipe is necessary. But if it is, I'd probably run a French drain along the edge of the patio (no wall portion).


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## Bondo (Dec 8, 2007)

Ayuh,.... I'd find the deepest point in the puddle that forms, 'n drill a 3/4" hole, straight down through the slab,....

The water will perk down to the drainage tile, all by itself,....

It'll take a hundred years before any erosion becomes any problem,....


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## stadry (Jun 20, 2009)

bondo nailed it best,,, write back in 100yrs & lettuce know how it worked out:wink2:


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