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Cut through joists

MilesD's Avatar

Join Date: Apr 2007
Posts: 1

04-03-07, 12:02 PM   #1  
Cut through joists

I would like to add a kitchen hood by venting through a 4" duct running through the joists supporting the floor above the kitchen. I need to cut 41/2" diameter holes through the joists, but the 2x8" joists are spaced only 6" apart where they need to be cut. The holes need to be cut through the center of the joists but I can't get a reciprocating saw high enough to cut the holes because the other joists are in the way. There are six joists to cut holes through. I can't access them by cutting through the outside of the house either. Are there other ways to cut holes though the joists?

I can't vent parallel to the joists either because the vent pipe has to end at a joist and it cannot be cut out

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chandler's Avatar
Banned. Rule And/Or Policy Violation

Join Date: Dec 2005
Posts: 39,968

04-03-07, 04:21 PM   #2  
Welcome to the forums! Don't cut a 4.5" hole in any 2x8 joisting. It will degrade the integrity of the joist and may you frown. How close to a load bearing wall is this location?

Wayne Mitchell's Avatar

Join Date: Dec 2005
Posts: 3,188

04-03-07, 08:15 PM   #3  
Chandler is right. Cutting large holes in adjacent joists may seriously weaken the structure. Have you thought about venting down instead of up?

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