# How much can you cut from joist?



## moranman (Jul 12, 2018)

Hey all,

I'm new to the forum here, but absolutely loving the information I'm reading about. I'm doing a small remodel in my basement and I'm looking for a way to cut down on how many soffits are in one of the rooms. I have a vent hose that comes in from the outside wall, drops down below the joists and connects to our furnace about 15' away (picture below). Is there any way to work this hose through the joist and then support the joist with a bracket or 2x4s? Any ideas on how to work around this would be really helpful.







Thanks all.


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## Francis Vineyard (Jul 12, 2018)

Suggest contacting the manufacturer or an qualified engineer
http://www.ahjengineers.com/wp-content/uploads/2011/11/Allowed-hole-charts-for-Trus-Joist-products.pdf


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## Pcinspector1 (Jul 12, 2018)

I-joist (webs) centers can be cut but not the flanges, there are limitations to the hole size that can be cut depending on the manufactures requirements, type of joist, depth of joist, distance from bearing, square, rectangle or round cut.

There may be information printed on the I-joist to help identify the joist.

With this information, you could contact the manufactures helpline or as Francis suggested contact an engineer for ways to eliminate the soffits. 

Hard piping may work, depending on the vent tubing requirements of your furnace. 

Can the vent piping be re-routed?


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## cda (Jul 12, 2018)

Welcome


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## moranman (Jul 27, 2018)

Wow, you guys are great. That's helpful. Thanks for the chart @Francis Vineyard

The piping can't be rerouted. I've thought it through so many ways. I could cut a new hole for the vent outside etc, but just not worth it. Any concerns about going through a reducer? 6" down to 4" so I could pass through the joist?


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## Paul Sweet (Jul 28, 2018)

You would need at least 2, and probably 3, 4" ducts to get the same airflow as a 6" duct. Another possibility is a 4" x 10" oval.  The main problem with either is whether there is space for the transistions.


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## RJJ (Jul 28, 2018)

Can't use a reducer. You probably need to re pipe the line as Paul suggested.


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