Man, the one truth out there is that you can learn from your mistakes. Today we completely stripped off the other half of the roof and laid down the OSB decking. The same process took us two and a half days last time. I find the biggest problem I have is that I am trying to do house carpentry with machine shop precision. This can only lead to frustration.
I am putting this info here as more of a recounting of how I did my house. This is not a how-to for how to do yours but more of stuff to consider that will make a difference.
When i was planning out the job, I was thinking in linear feet and not in actual materials placement. You tend to use a bit more materials because of the way the materials have to be laid out. Decking must be staggered, flashing and felt needs to be overlapped and clips, screws and nails will always require more than you think.
Materials are not created equal. I wish someone explained all these things to me when I was picking materials. I highly suggest that you research your materials. There are lots of things out there that look the same but are very different. These can include different grades of OSB decking. Some are for interior and others are for exterior. If you are using presure treated lumber, there are tons of issues that surround it. The chemicals used in the process are very corrosive and special screws, fasteners and flashing must be used. Think about the little things as well like plywood clips and felt nails. These are the little things that can crop up in the middle of the job.Again, take the time to research the process and how it will work for your project.
Safety is another big issue. You are working with power tools, hammers, etc. ten feet plus in the air. If you fall and break your dumb ass neck, that is your problem. Be sure to use the proper safety gear. Also remember the folks on the ground that are helping you out. Nothing says “howdy” like a framing hammer to the topof the head.
One thing to remember is to square off from the start. Now when you are working with an old house like this where square is optional, this can get interesting. When dealing with a metal roof like we are, you have GOT to get it on right. True that you can hide stuff under the trim but if the roof is not square with the trim, then it is going to look goofy. So, looking back on the job, this is how I would do it.
We have a tin on slats type roof. Remove all of the tin, eves and end rafters (not the structural but the decorative ones at the gable ends). Stack the tin neatly becasue people claim it has resale value. Leave the facier boards because we are going to use these later. Only remove a couple of rows of slats at a time so you don’t weaken the structure of the roof.
Make sure that you get all of the nails, staples and other things off the top surface of the boards. Check for splits and rot that needs to be taken care of. It is much easier to do this now than later. After everything has been cleaned off, attach the slats you removed to the facier boards so that the top edge is a few inches above the existing facier board. Secure it well with several screws because this is going to keep the decking from sliding when you put on the first row. It will also help to line up the decking if the ends are all cut even.
Once all of this is done, you are ready to start with the decking. I started at the corner and laid down the first row. Check to make sure that the edge is staying streight and square to the ends and rafters. Attach a few screws in each piece to hold it in place. If it’s the first side of the gabel then decide how much you want the eves to overhang. It can’t be too much without support. I don’t have that much faith that OSB and other engineered wood products will not try to droop in humid South Louisiana.
(On a side note, why is every damn do-it-yourself home improvement book written for the yankees? I haven’t found a damn book in the bookstores that deal with the issues we see here south of I-10. There are a couple of great building in South Louisiana books available but you have to know how to get them. If anyone is interested, send me an e-mail.)
Measure out the sides and ends a little long so that they can be squared off and trimmed down. This way you can make sure that everything is even and square. If it is the “other” side of the gabel roof, then extend the decking a few inches past the other side so that you can trim it back down to be even with the other side and everything will match. Chances are that your rough ends will end up at the roof peak. Make sure that when you measure the last row of OSB that you take into account that things might not be completely square at the point. The good thing is that the roof cap will cover these things up.
After the new end rafters and faciers are installed, roll out the felt. We used a new synthetic material from AlphaPro called Synthetic Roof Underlayment. This stuff is tuff. It comes on a roll and is easy to handle. The nail pattern is printed out on the exposed side as well as lap lines. It is a bit more expensive the traditional felt. Since I have never worked with traditional felt, I can’t tell you how it compares in terms of installation but this stuff has got to be easier. I will say that it scars easy. If you drop your claw hammer on it or scrape it with the tip of a screw gun, it does mark the surface. I don’t know if it damages the water proof properties but it can’t be good for it.
Since I used pressure treated 1×4′s and 1×6′s for the faciers, I extended the SRU (Synthetic Roof Underlayment) past the edges so that it will be a barrier between the flashing and the ACQ treated lumber. I don’t know how this will work out. The technologies involved are all still too new. Only time will tell but this will hopefully be the best of both worlds. Later, I will come back with a sharp knife and trim it so that it is flush with the bottom of the flashing and it won’t be seen.
I didn’t get the first side of the decking as square as I wanted to so I know that there will be issues getting the metal on and not looking retarded. Hopefully I will be able to come up with something between now and then.
I’ll complete this post when I am finished.