[TowerTalk] drilling through masonry

FireBrick w9ol at billnjudy.com
Mon Mar 14 20:10:29 EST 2005


As a retired licensed masonry contractor, let me tell you there is a right way and a wrong 
way.

Here is the right way.
Rent a combo drill/rotor hammer with long enough bits to reach through the wall.
Walls are a nominal 8" or 12" width.
You need more than one bit, a small diameter bit and a bit of large enough diameter to 
produce a hole capable of all the coax, cables etc.

Determine where you want the hole to exit the house, up from foundation, and horizontally 
from a window or already protruding object.

Now here is where most make the mistake. Measure so the starter hole is in the 'bed' 
joint. That is the horizontal layer of mortar.
After measuring again and marking the spot on the inside. Drill from the inside with the 
smallest diameter bit.
The reason you use the smallest bit it to make the smallest exit hole.
The exit hole will ALWAYS be much larger than the drill bit and may spall off surrounding 
bricks.
Then go back outside, and with the larger diameter bit, redrill from the outside in.

This will prevent spalling of adjacent bricks and make patching in the future much 
simpler/neater.

(for those who don't know, a roto hammerdrill is one that hammers and makes a 1/4 turn of 
the bit with each impulse. It will go through concrete or masonry much much faster and 
easier than a simple drill)


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Keep on a digging, the best bones are buried deepest!
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Bill H. in Chicagoland




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