# joining sheathing panels on roof



## Roofmaster417 (Jun 9, 2010)

amakarevic said:


> i was wondering if this is a sketchy way to assemble roof sheathing from multiple panels. the + section does not seem to solid to stand on. was wondering what i should do to reinforce it. was thinking of putting a 2x4 between the rafters and along the + line that's perpendicular to the rafters or perhaps use some steel connectors for lumber.
> 
> thanks


You have a 100% certified mess.I would *NOT* walk on that.First the seams and corners should *NEVER* be free floating.They should meet and end on a truss.I would pull the plywood and set some trusses equal to the existing trusses.2nd the plywood needs (IMO) a stagger of at least 4'(IMO).


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## tinner666 (Mar 14, 2005)

I hope it isn't nailed too tightly. You'll tear it up pretty bad when you remove it. Each piece has to be cut so it hits the center of a rafter. Very little scrap though as long as you laid the rafters out on 16" centers. And offset the rake so the first sheet, and the first 1/2 sheet correctly. The cut-off usually fit on the other rake.
Be careful taking it down.

BTW, it that's thin 3/8" -1/2" osb, I would put 2x4's between the rafters at the horizonal joints so each sheet lays on it when you reinstall them.


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## amakarevic (Apr 12, 2007)

i was wondering if it would be OK if i put a piece of 2x4 perpendicular to rafters to cover one axis of the + joint, if that would reinforce it? i would still have horizontal joints though.

this is on a shed that's 11x9


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## amakarevic (Apr 12, 2007)

as attached...


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## amakarevic (Apr 12, 2007)

i was wondering what's done when rafters are longer than 8' (standard OSB pane length) and you have to join two pieces of sheathing vertically. in that case, you will have a seam that goes across rafters and not alongside one.


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## seeyou (Dec 12, 2008)

amakarevic;609622[B said:


> ]i was wondering what's done when rafters are longer than 8' [/b](standard OSB pane length) and you have to join two pieces of sheathing vertically. in that case, you will have a seam that goes across rafters and not alongside one.


Oooh, man. I'm sorry, but you need to get down off the roof and re-group. I think you have the sheathing turned the wrong way. Plywood and OSB (ORIENTED strand board) have more strength in one direction than the other. 

4x8 panels are laid with the 8' side parallel to the ground with the 4' side landing on a rafter/truss. "H" clips are called for in some instances between rafters along the 8' side and help maintain proper spacing for expansion and contraction. 

Tear that mess off before you go any further and someone gets hurt falling through it.

edit: see housegsx's picture below for a stagger example.


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## housegsx (Oct 21, 2010)

You would use sheathing clips. H-clips.


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## amakarevic (Apr 12, 2007)

seeyou said:


> I think you have the sheathing turned the wrong way. Plywood and OSB (ORIENTED strand board) have more strength in one direction than the other.


which side goes inside and which goes out ?


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## seeyou (Dec 12, 2008)

amakarevic said:


> which side goes inside and which goes out ?


Usually doesn't matter. I like to put the rougher side up for less chance of slipping when walking on it. . 

It does need to be oriented with the 4' dimension parallel to the rafters and the 8' dimension perpendicular to the rafters.


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## amakarevic (Apr 12, 2007)

seeyou said:


> Usually doesn't matter. I like to put the rougher side up for less chance of slipping when walking on it. .
> 
> It does need to be oriented with the 4' dimension parallel to the rafters and the 8' dimension perpendicular to the rafters.


but you told me that it does matter above...

OK, i do have the 4 side parallel to the rafters and the 8 side perpendicular but doing it like that you will inevitably have a seam perpendicular to the rafters, unless your rafters are 4" or shorter. but i don't have H brackets in between panels. i would think if i use connectors on the inside to reinforce the seam, it would suffice.

so then i shouldn't have to tear the whole roof, just the end where the + incorrect joint is and trim the other side to the first next rafter and then cover the rest.


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## seeyou (Dec 12, 2008)

amakarevic;610026[B said:


> ][/b]*but you told me that it does matter above...*
> 
> OK, i do have the 4 side parallel to the rafters and the 8 side perpendicular but doing it like that *you will inevitably have a seam perpendicular to the rafters,* unless your rafters are 4" or shorter. but i don't have H brackets in between panels. i would think if i use connectors on the inside to reinforce the seam, it would suffice.
> 
> so then i shouldn't have to tear the whole roof, just the end where the + incorrect joint is and trim the other side to the first next rafter and then cover the rest.


No I didn't - apparently you miss-understood.

Yes, you will have a seam(s) perpendicular to the rafters. That's of no concern if you have the OSB oriented right. The joint between the rafters and having the joint in two rows of sheathing stacked is the concern.


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## fulton 22175 (Mar 16, 2011)

your sheathing is supposed to break at a 8ft point and in the middle of your rafter ( or the center ) it does matter which side is up the rough side goes up where the lines are at , stagger your sheets 8ft and 4ft if its possible its for strength , apply your H-clips , nail your sheathing every 6" inches on the outside and every 8"inches in the center and be careful i cannot stress that enough


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## amakarevic (Apr 12, 2007)

why is it important which side is up, other than for friction when walking ?

so let me know what you think of my plan to fix this (assuming it is not perfect to have the wrong side up, this is a shed for god's sake and it's not all so black and white, if it lasts 20 yrs, that's good...):

the part between the front of the shed and where the mistake is (the + joint) is only about 25% of the roof. i was gonna nuke that part and then also nuke the side on the other part of the + but just to the middle of the next rafter. i can take nails out and sister that rafter on both sides so that the nails go into the sisters and not into the rafter because both the rafter and the sheathing in that area will have too many holes from before. then resheath what i nuked, the proper way. i still won't have the H clips along horizontal joints but then again just think outside the box for a second - if i connect the s**t out of the panels using steel wood connectors (that you can get in the same section of big box stores as decking connectors), then that should emulate the strength of H connectors, should it not ?

please let me know if this sounds like a plan

i know y'all think by the code but i stress this is not a house, it's a shed and it doesn't have to be built to survive a nuclear attack.


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## seeyou (Dec 12, 2008)

The time and effort you will likely spend doing it wrong will probably equal the time and effort you'd spend doing it right. 

You asked for advise. You've been given the same answer from numerous different people. I have nothing more to say.


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## kwikfishron (Mar 11, 2010)

It's just a small shed, you could just add a rafter at the vertical seams and also add a stud since your wall sheathing isn’t breaking on a stud either. 

It’s either that or tear it off and do it right.

Some of the best lessons I’ve learned in building have come from “pulling nails”.


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## MJW (Feb 7, 2006)

If you were paying for it, would you want it done right?

Do you do your day job correctly or is it always just "good enough"?

Do whatever you think is easiest. Why would you ask if blocking would be a problem since it's "just a shed"?

I'll propose a ban if you say 'nuclear' or 'dude' again! Ha j/k


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## Ed the Roofer (Jan 27, 2007)

Regardless of How or even If you would be able to reinforce the underside of the mis-installed sheathing, how would you secure the sheathing to the newly installed rafters or whatever else you may be considering?

Sooner, rather than later, the edges of the decking will puncture through the surface shingles creating a future mess to once again contend with.

My advice would to not make an incorrectly installed project even more of a problem than you already are contending with and rip it all off and do it again properly.

Please review the deck sheathing specifications from the American Plywood Association, which now currently goes by the name of Engineered Wood Products Association, so that you can visualize the correct installation process.

Ed


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## fulton 22175 (Mar 16, 2011)

the lines on the rough side of the OSB are layout lines marked at 16" and 24 " so you can see your rafter lines up and you can make sure your nailing the rafter thats why the rough side goes out and you get better traction too


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## Gary in WA (Mar 11, 2009)

The waxed side with the inked span rating (label) goes toward the room so the Inspector can see the material rating for the application. It is waxed for the press release when pressure-gluing the chips together at the possessing plant. The lines are for your benefit when nailing. Be sure to leave the required 1/8" gap between edges and ends as per directions with OSB; http://osbguide.tecotested.com/pdfs/en/el812.pdf

Gary


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## tinner666 (Mar 14, 2005)

Since nobody including myself has mentioned it yet, I will now.
The OSB has to be staggered over 2 more rafters for it's shear strength. Even if you managed to add a rafter, stud, and crossbrace to the mess, the building 'moves' as it ages, for wont of another word. 
If all the sheathing meets at the same point in the building, all the nails in the world won't keep it together. Wood moves. It's not stable like you think it is. Nor is the world. Wind will accelerate the issue too. 

Pop the sheathing off, safely, and reinstall it correctly. Please.


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## amakarevic (Apr 12, 2007)

what do you mean by "staggering" ? is it the zigzag position on horizontal panels relative to the row above/below, as to avoid + joints where 4 panels meet ?


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## tinner666 (Mar 14, 2005)

amakarevic said:


> what do you mean by "staggering" ? is it the zigzag position on horizontal panels relative to the row above/below, as to avoid + joints where 4 panels meet ?


 Yes. The first panel can be nominally 96" x 48". Then, nominally the second course above it would be 48" x 48".

This puts the joints 48" apart and gives the structure it's strength. THat would be a 3 joistrafter stagger when the studs are set at 16" OC. 2 stud stagger when set at 24" oc.


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## tinner666 (Mar 14, 2005)

To get proper spacing of studs, once the floor is down, I'd pull the tape from an outer edge, anda t every 'Red' 16" mark, I'd deedcut 3/4" and mark the edge of the stud, and put an X at the 16" spot. Doing this guaranteed that a full 8' sheet would hit the center of a stud. Same for the 48" sheet.
When all the wall, floor and roof measurements were done this way, AND laid out so the dimensions of the building are divisible by 4', there is no scrap. ( Or at least so little as to not make a difference.)


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## amakarevic (Apr 12, 2007)

do you think after i pull out so many ring shank nails, the rafters will be weakened?


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## tinner666 (Mar 14, 2005)

amakarevic said:


> do you think after i pull out so many ring shank nails, the rafters will be weakened?


 You should be OK. It's new wood, not old dry wood.


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## DexterII (Jul 14, 2010)

Amakarevic, the guys have given you great advice, complete with sketches, so I am not going to elaborate, except to say that I concur fully with removing the roof sheathing, and installing it properly. If you don't have one, buy a cat's paw to get the nail heads above the surface, then use a flat bar (often referred to as wonder bars), along with a scrap of wood for a fulcrum, to pull the nails out.

Now, to expand just a bit, I belive that I saw another thread in which you said that you were going to side this shed with cedar shakes, in which case, particularly with shakes, although applicable to other types of siding as well, you will have the same problems, i.e. premature failure of the siding, as you would with shingles on the roof, unless you take similar action with your wall sheathing. Also, your end wall sheathing lends significant support to your gable ends, when installed properly, and with it not meeting on studs, could contribute to a structural failure of the roof.

Lastly, you made another post regarding running electrical to a shed, which I assume is this one. If not already, sooner or later, an inspection is probably going to be requirred. So, whether or not you have pulled a permit for this shed, I will also point out, and I may be wrong, as it is "just a shed", that I believe you need a double top plate on your walls. There may be other issues as well, such as anchors between the walls and foundation, headers, etc., but I cannot see those in these pictures.

So, obviously up to you, but before going too far, you may very well want to consider talking with your local building department, to see what is required, because although it would be a pain to install a second plate at this time, it would certainly be better than seeing it condemned at a later date. And, even if you do have a permit, you may want to talk with them before continuing. In my jurisdiction, as an example, the building department will issue a permit for a shed without me submitting drawings, but they do so on the premise that basic construction techniques will be followed, and if I were to have that shed inspected, I am quite certain that it would not pass.

Just some friendly advice, opinion, or whatever.


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## amakarevic (Apr 12, 2007)

DexterII said:


> I believe you need a double top plate on your walls.


you mean two tiers of sheathing ?


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## DexterII (Jul 14, 2010)

No; am referring to the horizontal 2x4's on top of the studs.


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