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Is drilling in concrete block and poured concrete basement walls bad?

Is drilling in concrete block and poured concrete basement walls bad?

Old 12-27-19, 05:51 PM
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Is drilling in concrete block and poured concrete basement walls bad?

We live in a 45-to-50-year-old condo with very limited space, so I decided I'd attach shelves and the like to the basement ceiling (plan still in head, not on paper) and walls, one of which is concrete block ("shared" with neighbor); one, poured concrete (front of condo), which measures 4" up to what no doubt is the sill or plate for the front kitchen wall, so the pour was at least 8".

Somehow, the 8x12-foot "front yard" has sunk over the years before my wife bought the condo. She hadn't noticed (nor had I) until I saw water 3" deep standing at our foundation after a long, hard, spring rain. I'd seen it as high several times until we figured out the problem.

The problem was that the neighbor's downspout (sort of hidden behind his heat pump and vegetation) had gotten out of the groundwater pipe opening and was draining into our (including his) "front yards". He had it worse. Water would run into his basement window well and into his furnace room despite having a block glass window.

Water never entered our unit.

But after a spate of heavy rains this year, and unnoticed until I removed a cardboard box of Christmas ornaments from the floor of the storage area at the opposite front end of our unit, I found that a small amount of water had seeped in, but it was enough to waterlog a corner of the now-ruined box (inviting a family of many*-pedes reside there).
{ * - a hundred, a thousand, whatever it takes)

This is the only time water has entered our unit in 15 years.

But it freaked my wife out and so now she really doesn't want me to drill into either the block or poured wall.

Of course, the block wall is almost totally underground, but there's nothing I can see that would indicate "better not drill here", especially since the electric panel is mounted to it. Unfortunately, there's not a lot of lineal space for shelves. Hooks, maybe.

If water did in the future begin again to stand against the poured wall, which I doubt will happen, I really can't tell my wife that there'd be no way for 2.5" holes to let water in

There's not much lineal space on this wall, either. But I think I can safely drill 8 holes 3" deep to mount 30 and 40" shelves to hold laundry and detergent, bleach, cleaning products, etc. because the washer and dryer receptacles are mounted to it.

It's a little lame to use already-attached items as proof of concept, since the holes drilled are surely not nearly 3" deep. Probably not even 1" deep.

So I'm really unsure if it's safe or not to drill into the poured wall.

(1) What do you think?

So I'm not even positive that I should drill into the block wall.

(2) What do you think?

Thanks for any help.

Dave Slomer
Old 12-27-19, 05:55 PM
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Drilling into the walls will do no harm. If the fasteners are ever removed you can always patch or caulk the holes.

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