bmac said:
Also, I was planning to set the rafters 16" on center. Do I still need the H clips?
Also, assuming I eventually get the rafters cut and installed without breaking any bones (did I tell you I don't like heights?) when I put down the roof sheathing, do I place the edge of the OSB flush with the end of the rafter or do I allow enough overhang to overlap the facia.
bmac,
Since you said that you are putting down decking, and not purlins, I'm going to assume that you are going to use shingles for the roofing.
With your spacing, pitch and since there's no snow to deal with, you really don't have to use the H clips. They stiffen up the OSB between the rafters, but I honestly don't know if it's code for 16 inches or not. It is for 24 inches.
I like to install the facia boards before the decking. Before you can put them up, you need to have your gable end overhangs built. There are several ways to do this, the easiest is to double or triple up your rafters and have a 3 to 4 1/2 inch overhangl. It's solid and easy to do.
The proper way is to run an stud on edge from the second rafter in so that it rests on the top of the outside rafter. This means cuttind down the outside rafter or notching it. This is code, and the strongest way to get a one foot or longer overhang.
The easy way for a one foot overhang is to first install all of your siding to the peak of the gable ends of the buiding. This should end flush with the top of the rafters.
Now measuer the exact length of your ridge beam, and how far it extends past your siding. This is how long you need to cut your 2x4's. Use 3 or even 3 1/2 inch screws to fasten them through the rafter and have them on their edge. 1 1/2 inch side on top, 3 1/2 inch sides on the side.
Use three screws through the rafter adn then three more toenaild in from the other side. On the toenailed screws, I like to put two on one side, and one on the other.
This will work, but it goes against my grain to install anything that isn't supported by something else underneith. When properly built, every piece of wood should be resting on top of another peice of wood.
You'll notice that the overhang lumber will sort of twist and turn in it's own direction. This is where the facia board comes into play. It's not only to look nice, it's to line up your 2x4's and get them straightened out. Two nails or screws through the fascia board will do the job of securing it all together.
I'm guessing that you will use 1x6 lumber for the fasia. If you go smaller, then you will have to cut your rafter tails down to size. You can use 1x4's if you do this, it's just your call and what you like.
To add a small amout on strenght and allot of appeal, install a 1x2 at the top of the fascia board. This stiffens up the fascia quite a bit and gives the flashing a better chance of sheding water off of the roof. Homes without this strip tend to have fascia's with mildew growing on them from water running off of the roof and over the fascia.
If you are putting gutters on, then don't install the 1x2's on the sides, just the gable ends.
Now it's time to install your OSB decking. Try make the seams for each peice on a different rafter, or at least every other piece. Start at the bottom and work your way up. It's more important to have the full length of OSB on your overhangs. The same is true for your gable ends. Always make sure that every piece of OSB starts at the edge and is fastened into at least two rafters. Three would be allot better. NEVER put a short piece on your overhangs that ends at the walls. It must have multiple rafters on an overhang. If you find that you have short areas inside the middle of the roof, than cut one sheet of OSB shorter. Never have your decking installed just on it's edges. You always want it to be on at least three rafters with four being better. NEVER have it on just two rafters.
You might find that you need a short strip at the peak. That's fine since it's not as important as the fascia ends of your decking.
Once your OSB is in place, install your flashing ordrip edges. A basic 90 degree angle flashing with one end kicked out a little bit is the most common. there is also T flashing that is a little bit more money, but works better. Price wise on a small building is only a few bucks. I always buy the T flashing.
How are you going to vent the building? Roof vent or gable end vents? Both have their advantages, so it's up to you on what you like. The peak vents are the most attractive, but probably overkill for you building. A turbine is proven to be very effective, but sort of ugly. Gable vents should work real good if installed on either end. Probaby add to the charm of the building too. I think that's what I would use, but it's up to you.
Next, you need to get your felt paper up right away. The longer the OSB is exposed to the elements, the rougher it will get. I prefer to staple it on and get the shingles on right away. If you have to leave the felt paper exposed for any period of time, then you will have to nail it down with nails designed for this. I forget what they are called, but you can't miss them. Small nails with giant plastic washers on them. Put them down on the edge of the paper and in the middle about every two feet.
15 pound paper will work and it's used on new roofs all the time. It's half the price of 30 pound paper and lighter to work with. It's also half as thick and in my opinion, half as good. For the money, the paper you use is just about the most important part of the building. I always spend the extra on the paper and buy 30 pound. You won't need much, so it's not really a big savings going with the thinner stuff anyway.
Be sure to roll the paper along the bottom first and work your way up. You can either pre cut your paper with some extra and trim along the edge of the flashing, or you can unroll and cut in place. I unroll and cut a little long, then trim after it's fastened down.
If you are putting in a roof vent, you need to cut the decking for it now. Then when you are installing your paper, you need to put your first layer of paper down so it covers the hole, or at lest part of the hole. Then cut it out for the hole. Then install the vent, and lay down another layer of paper so that it overlaps the vents flashing. On a peak vent, you don't have to worry about the paper until you get to the peak, then it's pretty straight forward. Just be sure not to put the paper over the opening for the air to travel.
Shingles are shingles. Three tab are cheaper, but sort of plain and ugly compared to raised, or archetecural shingles. Matching what you have on the house is always a nice touch, but it doesn't really matter what ones you buy, they all install pretty much the same way.
You start at the bottom. It doesn't matter wich corner you start at, just as long as you start at the bottom. Your first row is called your starter strip. they sell shingles cut for this, or you can turn your shingles upside down and put it in that way. Always have the rock side up. What I do is buy a few bundles of flat 3 tab shingles in the same color as the raised shingls for the starter strip and my peak shingles. They are cheaper and work great for the starter strip. Then install you first shingle. You can work off of the eges as your line, or follow the lines on the tar paper. The bag that the bundles of shingles come in have instructions on where to nail the shingls. I've seen people do it all sorts of ways, but the only correct way is how the instructions on the plastic wrapper says to do it.
Overlap your seams by either using the left over shingle from the first run to start your second, or cut off one or two tabs from the first shingle of your next run. This will put the seams in different places for every three runs.
For the peak, I cut the three tab shingles into three pieces. A standard utility knife works great for this. Start at the ends and work your way in to the middle. When they come together, you will have to cut a final shingle in half to finish it off.
You will notice that they sort of stick up a little and don't lay flat. This is normal and will change when the shingles get hot. The sun will relax the tar in the shingles and melt the glue that holds them together. After just a few days of warm weather, your shingles will lay flat for you.
Have fun,
Eddie
