Subfloor doorway install


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Old 01-31-19, 08:37 PM
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Subfloor doorway install

My doorways have only 2 joists 27" OC that I can attach a subfloor to. Is it ok to just use one panel spanning 2 joists side to side or does this whenwe the panel? Normally you have one large piece of plywood covering multiple joists
 
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Old 02-02-19, 03:17 PM
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Your sheets have an APA stamp on them that tells you the spacing that the sheets are rated for. For example:

https://www.apawood.org/Data/Sites/1...atasheet-o.pdf

https://www.norbord.com/na/wp-conten...Mar-7-2017.pdf

Additionally, their instructions state: If T&G panels are
not used, panel edges must usually be adequately blocked... especially so if you are over 24".

So at a minimum you would add blocking every 4 feet (at all panel edges).
 
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Old 01-31-19, 09:12 PM
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As mentioned in one of your other threads on this subfloor topic... you should be putting blocking between the joists. The utside edge of the subfloor will be landing on that blocking in addition to the 2 joists in your doorway. And you can add additional blocking parallel to the rim so that you can add additional framing parallel to the joists as needed along the edges of your rough opening. You will want solid framing around those edges.

Normally you would probably want one full sheet to be notched out and go into the doorway... all other sheets along that wall would get a few inches ripped off the width of the sheet so that they all line up.

You might consider keeping similar posts dealing with the same subject (your joists and subfloor) in the same thread. The other thread provides all the background info and context of what your project entails which helps people to answer.
 
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Old 02-01-19, 12:42 AM
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It's an awkward measurement since one side is a halfway that's exactly 4ft and fits a plywood width.

Normally you would probably want one full sheet to be notched
ifi could notch, how far into the doorway should it be?
 
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Old 02-01-19, 06:54 AM
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All the way. You want to avoid having any little pieces.
 
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Old 02-01-19, 11:18 AM
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As the hallway is 4' wide. Is it better to have 2 times 2' plywood down the hall then make a notch out of that and have a tiny bit 4' wide?
 
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Old 02-01-19, 11:31 AM
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I don't know the layout of your entire subfloor so it's pretty hard for me to say. Sheets of plywood are always laid perpendicular to the joists. So even if the hall is 4' wide your sheets must be cut so they lay perpendicular.
 
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Old 02-01-19, 06:47 PM
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For the blocking, I am having trouble getting it to stay in the same place when nailing it in. I am manually nailing rather than using a framing gun, so every time I hit the nail in, it just moves the block a little bit. Any tricks?
 
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Old 02-01-19, 07:10 PM
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Yes, cut it longer than you have been so that it's tight. You can use construction screws as well.
 
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Old 02-02-19, 02:56 PM
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Lastly, my joists are 27" OC. I'm using 3/4 OSB as I couldn;t find 7/8. Is it worth putting blocking every 2' under the plywood for more support or is this overkill?
 
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Old 02-02-19, 03:30 PM
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Let's say the span rating is 24 but I want to use that anyway and it's T&G...would it be an idea to make it firmer with blocking every 2ft so it's halfway under each panel?
I'm at the limit I think at 27"OC.
I suppose it would be just as good to put a 2x6 on each side of the joists effectively making them 24OC. I've already levelled one side.
 
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Old 02-02-19, 03:39 PM
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Well, its overspanned by 3" so I guess that's up to you. I would say that 2' on center blocking is not worth it. If its not t&g I would do the panel edges (every 4 ft) like the instructions state.
 
 

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