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drill 4" hole through rim joist???

ontario026's Avatar

Join Date: Mar 2006
Posts: 14

09-15-06, 10:50 AM   #1  
drill 4" hole through rim joist???

In order to install a bath fan in a main floor bathroom with a finished floor above it, is it an acceptable practise to drill a 4" plus hole through a rim joist?? my regular joists appear to measure 7.5"x1.75" so I would assume the rim joist would be the same...


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chandler's Avatar
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Join Date: Dec 2005
Posts: 39,968

09-15-06, 03:57 PM   #2  
Answered in another forum.. Cut a 4 1/4" hole or you won't be able to run the duct nor attach the flap outside.

pgtek's Avatar

Join Date: Oct 2004
Posts: 1,391

09-23-06, 07:58 PM   #3  
no no

you cant drill a 4 in hole in a 2x8
max would be 1 1/2
why not run between the joist and cut hole in outside wall

Concretemasonry's Avatar

Join Date: Mar 2005
Posts: 6,125

09-23-06, 08:16 PM   #4  
drill 4" hole through rim joist???

A rim joist is on the outside wall and does not span like an interior joist, except possibly over a small window.

There might be a problem with local terminology.


jaybird20's Avatar

Join Date: Dec 2005
Posts: 67

10-09-06, 10:20 AM   #5  
Verdict on the duct holes in a rim joist?

So can you drill larger holes in an exterior facing rim joist to you can run duct thru them?

Followup: what is a good article or website that shows about framing house structures and how loads a taken by various parts of the framing?
THanks all

BuiLDPro68's Avatar

Join Date: Mar 2006
Posts: 532

10-09-06, 02:25 PM   #6  
I have done that procedure dozens of times with the blessing of the inspectors. In fact I don't recall it even being mentioned. The way I usually end up doing it without the huge expensive hole saw is to trace the vent fixture and then going a little outside the lines to allow room for the flex ducting, I drill a series of 3/4" holes around the circle with a ship auger bit. Then I connect the dots with a sawzall.

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