Cutting Joists - Carpentry - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Carpentry


Thread Tools Display Modes
Old 09-22-2010, 11:08 AM   #1
Join Date: Sep 2010
Posts: 2
Rewards Points: 10

Cutting joists


Thank you in advance for any direction. Not sure if this is a dumb question………..

I am trying to build a basement bar and want to "move" a wall back into a storage area to gain more space. The HVAC blower is directly behind this wall and there is space to move it back.

The wall is load bearing and has an 8" steel beam. I am not planning on moving the beam. Rather, it will be wrapped with drywall and create a 9" soffit back to the new wall where I can put lights in etc.. The problem is the duct work. The joists start to run perpendicular at beam and the current 8" ductwork runs under the beam (giving an approximate 17" soffit with the drwall) and then moves up and sits in between the joists on the other side of the wall - that run the "right" way.

Question: Can I cut the joist closest to the beam so the duct work can run over the beam? If so, what type of support is needed to go around it? I uploaded a Visio JPG drawing that shows this. The view is looking down. The 1st floor sub floor would be sitting on these joists.

Thanks again for any help.
Attached Thumbnails
Cutting joists-basement-bar-design-duct-work.jpg  


Last edited by elvis123; 09-24-2010 at 08:57 AM. Reason: Changed drawing - back joist does not sit on I beam
elvis123 is offline   Reply With Quote
Old 09-25-2010, 12:19 PM   #2
Join Date: Apr 2008
Location: Western Masschusetts
Posts: 575
Rewards Points: 500

surprised no one has answered this yet.
i'm sure the "you need a structural engineer" crowd will chime in after my reply.
anyway, if it were in my house and in my way i wouldn't hesitate to chop out that bay, assuming you can:

double up the joists on either side of the duct and run them long to the next perpendicular joist, which should also be doubled. if that's prohibitive, at least make some sort of partial sister carried long to the next perpendicular joist, at least on one side.

and make sure there is nothing directly above the bay you want to chop out that relies on that direct point load.

if you simply chopped out that bit of joist and did nothing else, i'm willing to bet that in the end it would have zero effect on anything, although i'm sure the "get an engineer" guys will scold me for that.



wombosi is offline   Reply With Quote
Old 09-26-2010, 10:07 AM   #3
Join Date: Sep 2010
Posts: 2
Rewards Points: 10

I truly appreciate your candor.

There is a load bearing wall that sits directly on top of the 8" steel I beam joists - the ones going in the "right" directing (where the duct would sit between) - not the joist I want to cut. The start of the kitchen floor is above it.

The span of the joists are about 13" feet - starts at the foundation of the house and ends on another I beam. I would be cutting about 11 feet in from the foundation, 2 feet from the side I beam.

I was thinking the same - sistering and joist hangers on the next board.
elvis123 is offline   Reply With Quote
Old 10-12-2010, 02:47 PM   #4
Join Date: Oct 2010
Posts: 5
Rewards Points: 10

If you have started oh well. YOU DONOT CUT JOISTS......The previous person that replied to you was correct. You would need a structural engineer.
greyowl is offline   Reply With Quote
Old 10-12-2010, 03:32 PM   #5
Join Date: Sep 2010
Location: Ontario, Canada
Posts: 13
Rewards Points: 10

Yes you can cut floor joist and you do not necessarily need an engineer. Your case looks fairly simple; you can cut the joist in question if add a header across both cut ends. The header would run from the steel beam to hangers on the next uncut joist, and the cut joist would also set into hangers on the headers. There are codes governing the length of the headers, but spanning for a single joist would be well within the code
Now depending on the load/bounce of the kitchen floor in this area you may want to consider doubling up the joist before attaching headers.
Hope this helps
Paul is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
When cutting ceiling joists, how thick should the header be? dwoloz Building & Construction 11 08-20-2010 03:58 PM
Cutting through floor joists chacha_m Building & Construction 26 05-10-2010 01:18 PM
Floor Joists of different sizes HooKooDooKu Drywall & Plaster 7 02-04-2010 05:43 PM
Cutting metal joists? 1forest1 Building & Construction 9 04-17-2009 01:34 PM
Sister or Replace Floor Joists brando1118 Carpentry 25 10-26-2008 08:43 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1