Removing 2x4 supports on attic joists

sbooth1440

Hi there - TOTAL newbie here, so be gentle! Total DIY'er, look forward to asking/helping!

I am laying some 3/4" OSB flooring in my attic. It's a large attic (35x60) with full stairs leading up, and joists 16" OC. Just for storage, now finishing completely...right now

My question is that, in two spots on the joists, there are 2x4's running perpendicular to the joists. Looks like two 2x4's about 18 ft long, slightly overlapped (tried to attach picture - hope it worked, and helps). On each side of the each 2x4 there is a 2x6 nailed to it. These constructs are not connected on either end to, well, anything - they just stop. The issue is that in two spots they interrupt the flow of the floor.

My assumption (yes I know - scary word!) is that these were installed when the house was built to provide some level of support to keep the joists aligned. My question is, since I am installing the flooring, and screwing it to the joists, can I safely remove these as the flooring will keep all in alignment?

Thanks for any and all help!

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Joe Carola

What size ceiling joists and span are they, and what you you finishing as?

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Joe Carola

sbooth1440

Hi Joe! Nice to meet you - at least virtually

Right now I am just finishing the room with flooring for storage. Some day maybe a guest room/playroom - nothing ever too fancy - don't think I'd every put a bathroo, up there.

The joists ar 2x8's. When you say span, my "newbie-ness is going to show here". They span the lenght of the attic - about 60 feet. There is no additional perpendicular header - if that's the right term(?) anywhere in the attic. It looks like every 15 feet or so they staggered/overlapped the joists. Put another way - I could run a wire the full 60 feet the length of the attic between joists and not hit anything. Does that make sense?

AndyGump

I suppose it is possible that they are just strong backs left over from the original framing and are not structural members in any way.

Hard to tell from a couple of pictures though.

Andy.

sbooth1440

Boy am I loving this site already!! Being a geek I googled "strong back" (figured I'd try to learn on my own before bugging you fine fellows) and saw this:

"A strong back is a member that is made up of a 2 x 4 nailed flat
on top of the ceiling joists. Then a 2 x 6 is stood up vertically
and nailed to the side of the 2 x 4. This is to strenghten the
ceiling joists and help to hold them straight."

That is exactly what I have up there - so now I can call them something

Off of Joe's question I did confirm that there is no additional perpendicular support structure to break up the run - so it's a run of 60 ft or so of joists. Makes sense to have the strong backs up there. (Look at me using new terms).

Definitely won't hold you to anything, but my take would be that with me putting down the OSB flooring and screwing them to the joists, this would do the job of the strong back - so I would be ok removing them?

Again - thanks so much for the replies!

mrgins

Neither OSB nor plywood laid flat will take the place of a strongback. The span measurement is the direction that the 2x8 joists run which I believe you said was 35'. It depends on what the clear span (unsupported area) that the joists span as to what you need to do. Assuming you will have kneewalls on either side, you could build them to double as strongbacks, but it depends what the 2x8's are supported by underneath.

sbooth1440

Thank you! The span is actually 60 feet (the length of the attic). Not including what is undernath the entire run is unsupported (meaning no perpendicular headers, etc.). In other words, I could remove the insulation and see the full 60' between joists. I'll need to take a look to see where they are supported underneath.

One quick question on your comment - the strongbacks aren't connected on either end. I am no engineer, but I think that is keeping the joists alighned, but is it doing much to, say, keep this long expanse from sagging in the middle?

Thanks again!!!

mrgins

It's keeping them aligned more than anything else. What length and material are your rafters if they have no support?? I'd be surprised if the joists weren't already sagging

sbooth1440

The rafters are 2 x 10's.

I went back into the attic and realized, after digging in through the blown in insulation - that the strong backs are supported on the ends. There are "headers" running parallel to the joists along each side of the attic and the strong backs are resting on them.

My realization is that I need someone who knows what they are doing to come take a look at this. It's tough with the insulation down, etc. to get a good read.

Thanks to everyone who has replied - I really appreciate it!!

Steve