Holes through masonry walls

11 years ago

I'd like to vent the hood in our kitchen through an exterior masonry wall. The wall is standard brick on the outside, backed my 4" masonry block (constructed 1950s). I can cut a 3.25" x 10" rectangular hole, or a 6" round hole for ducting. With either hole, do I need to be concerned about reinforcing the hole or adding a lintel? I'm leaning toward cutting around hole, since it eliminates the chance of leaving a whole brick unsupported.

I wonder if anyone else has come across this. Thanks for your help.

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Comments (7)

geoffrey_b
11 years ago
I've had an 8" hole cut in my masonry home for a combustion vent. No problems.
jschu121
Original Author
11 years ago
Thanks. It seems like a fairly routine operation, it's just hard to find a definitive article or resource discussing the issue.
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brickeyee
11 years ago
Holes up to about two bricks in size do not normally require a lintel.

I typically put in short piece of vent 1 inch larger than the required one, then back fill all around that with cut brick and mortar, then slide the actual vent through the larger one.

Back fill the inner block also.

This post was edited by brickeyee on Thu, Apr 11, 13 at 13:17
southerncanuck
11 years ago
Concur with Brickeyee. When we have done a rectangular cut in brick and or block, sized larger than vent and boxed with dimensional lumber. Helps when fastening vent to opening and adding exterior cover.

For circular, slid in steel pipe into oversized opening and cut circular closed cell insulation boards, one for interior and exterior to fill gaps. Did the same for rectangular opening.
jschu121
Original Author
11 years ago
Thanks for the tips brickeyee and southerncanuck. I recognize your names from other threads and have learned a lot from your posts.

I really like the sleeve idea. It will seal the hole well, and make fore a strong, tidy job.

My fear with the rectangular vent is landing in the middle of two courses of brick and having to chisel horizontally across the bricks. My thought is that with a circular hole, the cuts across each brick will be smaller. Do you guys generally prefer a round/rectangular hole?

Thanks again for all your help.
southerncanuck
11 years ago
Personally I like a rectangular opening. Easier to make unless you have the appropriate masonry hole saw. Then a circular hole. I couldn't justify the price for a few holes. Rental may be an option for you.
brickeyee
11 years ago
For round venting I make them as close to the desired size, and then use any removed bricks to cut and fill in around the sleeve.

I removed a Viking rage hood from my house before selling, and it was easy to repair the opening in the brick exterior (though it did take a few spare bricks that had been sitting in the basement since the house was built in the middle 1950s, this about 8 years ago)

This post was edited by brickeyee on Sun, Apr 14, 13 at 11:42