# Drilling Through Concrete Wall



## Termite (Apr 13, 2008)

I don't see any issue with drilling a 4" hole in a concrete foundation, provided that there is at least a foot of concrete over the top of the hole, and provided that the hole is a foot or so away from the other hole. 

Rebar simply keeps the concrete from moving too far when it inevitably cracks. A hole could theoretically weaken the concrete and create a stress point, but it is a small hole. They often cut entire windows into concrete walls with no ill-effects.


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## rjordan392 (Apr 28, 2005)

Thanks,
I am bringing my vents (two) up to code. I just learned that my existing setup with two vents (bathroom and Gas dryer) going into a wye connector before exiting the dwelling is not code approved and that each should have their own vent.


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## Termite (Apr 13, 2008)

Oh good golly my heart just stopped for a second. :no:

You definately have a dangerous installation there, as the combustion gas from the dryer (carbon monoxide!!!!!!) definately needs a dedicated vent. 

Glad to hear you're taking care of it. :thumbsup:


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## rjordan392 (Apr 28, 2005)

I had a backflow preventor placed on the bath vent duct to prevent air from the dryer from backing up into that duct. The dryer is only a few years old and the combustion is good so far. So I will make corrections this week.


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## yesitsconcrete (May 11, 2008)

either diamond core the hole or hammer drill series of holes on the circumference & punch out the core,,, if you run into steel, move the hole if using the hammer drill,,, coring can cut the steel,,, coring isn't easy for a diy-er - suggest hammer drill & 3/4" bits.


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## rjordan392 (Apr 28, 2005)

Thanks for the tips. 
I already used a core drill with a diamond bit. It took about 30 to 40 minutes to go through 9 inchs of concrete. The tool rental and diamond bit only cost $70.62 for 4 hours. I returned it in less then 2.


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## yesitsconcrete (May 11, 2008)

good for you,,, just curious,,, wet or dry & did that price include wear on the bit ??? for that thickness, we wouldda done it by hand w/weka 3speed 110v drill made by the germans


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## rjordan392 (Apr 28, 2005)

I drilled dry. The price includes everything including the tax. I rented from Home Depot. The drill hammer was a "HILTI" 1-3/4 SDS. I used a small worktable to rest the hammer drill on as it was too tiresome to hold it.


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