I am planning on Installing a Vent hood the manufacturer recommends 8 inch duct work.

I am looking for options to make this hole.

1) Diamond hole saw.
I couldn't find a diamond hole saw in 8 inch.

2) Core Drill
But I will get a clean hole. My question is how do I measure the thickness of exterior wall. I have brick which is about three inches. I measure the wall thickness near my garage with brick it comes to around 10 inches. Is this correct ?

  • Is hammer drill out of the question? With a wide bit? We talking square or round duct? – The Evil Greebo Aug 1 '18 at 15:55
  • There are companies that specialize in cutting holes in all types of brick, stone, or concrete They are not cheap but the do great work – d.george Aug 1 '18 at 17:03
  • 2
    3” brick 1.5” air gap 1/2” sheathing 5.5” stud 1/2” drywall= 11” wall you will want to be certain you don’t have a wall stud in the way of your proposed hole. An exhaust vent kit with a damper in it will provide some cover for mild imperfections in your brick hole I generally drill a bunch of small holes around the perimeter of a circle drawn on the brick. Then chisel away the remainder between holes. Use angle grinder to perfect the opening for the duct. – Kris Aug 1 '18 at 18:28
  • I am looking for 8 inch diameter square hole. I can use Milwaukee M18 hammer drill but can’t find diamond hole saw with 8 inch diameter. @The Evil Greebo – gopal Aug 1 '18 at 18:44
  • Hole saws don’t cut square holes – Kris Aug 1 '18 at 21:02

1 Roto hammer (rent from local tool rental company) enter image description here

1+ Chisel bit(s) enter image description here

1 8" circle drawn on the surface you wish to cut through

1+ hour of tedious, annoying, possibly painful labor

After you get your hole and ensure the vent fits, be prepared to seal any gaps with concrete caulk, or exterior vinyl caulk, or whatever suits your fancy.

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