Sheathing and a Big Misstep (Roof Part 2 of 5)

So with a slightly larger than 4x8 section of shingles and tar paper, it was time to tear off the sheathing.  As with everything I did, I wasn't sure how difficult it would be to remove.  The answer is: not easy, not hard.  They make specialized tools that I considered, but $204 after shipping was too rich for my blood.  I ended up going with a $12, 36" pry bar from Lowe's.  In hindsight, would the tool have been worth it?  Maybe.  But I still would have needed the pry bar.  If I were a contractor doing multiple roofs, I'd definitely have one of those tools.

Getting the first of the 1x8 boards up was difficult, because I didn't have much space to get the pry bar into.  Once the first was removed, I had space to get the pry bar into, and the remaining boards were easier (not easy) to remove.  As far as my method goes, if the board was already up slightly, and I could get the pry bar between the board and the rafter, I would pry that way.  If that wasn't possible, or if I needed to get the board started, I would position the curved end of the pry bar next to the rafter and yank up, allowing the upward momentum of the prybar to pull the board up.  Repeat, repeat, repeat.

As far as how the 1"x8" boards line up with the 4'x8' sheets, they don't.  At least not with gaps, and with the need to have space to work.  So with the first 4'x8' section (48" high), I had to remove 56" worth of sheathing.  And pretty much none of the 1"x8" boards were exactly 8' long. I had some that were 16'-20' long.  What I ended up having to do, since I was working in sections over multiple days (lets be honest, weeks and months), was to use a circular saw to cut just past the rafter, 8' over from the end.  You can see that in the above image.  That made for some largish areas that I couldn't walk, as the old sheathing was then only supported on one side.  I didn't break any boards like that; they just sprung slightly like a diving board.

However, I did make a mistake fairly early on.  On one small section, I removed the sheathing but left the tar paper in place (over the newly created space into the attic) for "water proofing purposes".  It cost me, as I stepped on tar paper that I thought had sheathing underneath it and went into the attic.  At first, I thought my foot just hit the insulation, but I was mistaken. It hit the drywall as well.

Well, crap.

This was earlier in the day that it happened.  I didn't bother getting off the roof until that night and looking.  When I showed Sarah, she was dumbfounded that she hadn't noticed it earlier.  She had gone through the room several times, never looking up.

Duct tape fixes everything!

It looked stable, so I duct taped it in place, and to be honest, is still like that several months later.  It'll be fixed soon.  I keep telling myself that.

Digression over, back to the roof.  There are a few sections on our ceiling where there's evidence of old condensation where the wall meets the ceiling.  It occurred in the winter, and I figured it was because of lack of insulation.  It's where the roof comes down to the eaves, and it was difficult to get the blown-in insulation correctly installed there.  With the sheathing off, that because quite evident.

You can see in roof bays 1 and 3 (numbered from the top), from the left, you have fascia, soffit, screen (used to keep insulation in/bugs/squirrels out during the soffit project), the 2x4 "top plate" (what the rafters sit on), and then drywall.  Just dirty drywall.  The ceiling.  So, without the blown-in insulation (as seen in bays 2 and 4), the cold air in the attic in the winter would hit the warm drywall, heated from the inside.  The drywall would cool significantly, and moisture in the house would condense on the cold surface: the ceiling.  The water, not large amounts but enough, would soak into the paint/drywall and eventually cause a small stain.

In the corners of the hip roof, there were batts of insulation that were installed 53 years ago, when the house was new.  53 years worth of hot/cold cycles in the attic, and the paper on the insulation just turned to dust.  Both that insulation, as well as the sections missing blown-in insulation, were fixed and replaced before the sheathing went on over it.  That should hopefully keep things good for the next 50 years.

As far as attaching the plywood, I used the standard nailing schedule (every 6" along the outside edge, and ever 12" along the inside) with one small modification.  On each of the four corners, I used a stainless steel deck screw.  This was just for peace of mind, a little extra hold down on the plywood.  I also staggered the sheets at least 2 rafter bays, and used H-clips in each of the rafter bays.  These are used to prevent sagging, and to tie each sheet of plywood to the ones around it.

As far as the framing nailer I used, it was a cheapie from Harbor Freight.  I think it was only $60 after coupon.  Pro tip: Never buy anything from Harbor Freight without a 20%-off coupon. They're everywhere, and you can even pull up the coupon from their website on your phone.  The money I saved on the nailer, I used in buying nice Hitachi nails.  Ring shank, galvanized, full-head nails.  I figured the nail was more important than the nailer.  Once the nail is in place, it doesn't matter what put it there.