I have a 12′ addition with broken, split and some rotted rafter tails. The rafters are on 2′ centers and 2×6’s. I want to replace all of them sistering a 2×6 to each rafter. The old soffit was angled back to house and I want to change it to a squared soffit.
How do you determine a new plumb cut for the facia and level cut for the soffit on the new tail and how far does the sistered tail need to extend up the old rafter?
I also want to cut the old tails back to the top plate and tack a small tail piece alongside the sistered rafter piece to maintain the original spacing.
Thanks,
Sicilian
Replies
Sicilian, if I had good nailing, and I was building a closed soffit system, I might be satisfied with as little as a one foot lap, if I was only going out a foot.
I'm assuming that your "squared soffit" is the same as my "closed soffit".
The reason that you can get away with so little of a lap is because the closed system offers some diagonal internal support that isn't available in the open "angled" system that you had.
A general rule of thumb is 3:1 ratio for cantilevers. That would tell you that you had to go back 3' for a one foot overhang. I'm thinking you could easily get back 2', but if you want to be conservative, use the 3:1 ratio and you could beef it up internally and carry quite a substantial load.
blue
My soffit is closed and the soffit board is angled back to the house about 45 degrees instead of straight back, and is nailed to the bottom edge of the facia board.
I want the remodeled soffit to have 90 degree box (L-shaped) so that the soffit board will nail to bottom of the rafter tail and nailer on the house.
Is there a standard overhang length for a soffit? 12 inches?
Thanks
Sicilian, there really isn't a standard sized overhang. The decision is based on many factors.
Probably 90% of what we build is a 12" overhang at the eaves and 6 or 8" at the gables. I like that look for most applications. It offers a good proportion for the normal 6" fascias and 5" gutters. But, I'm soon starting on a Frank Loyd Wright type house that will have 3' soffits.
Keep your overhangs proportionate to your house, unless you're doing something more creative.
blue
How do you determine what your plumb and level cuts on the new tail will be since it is different from the original rafter?
Thanks again,
Sicilian
Sicilian,I hope you don't mind me chiming in here but what I do is fo a 1' overhang is nail around 40" 2x's on each end of the house 20" minimum up the side of the existing rafter running them long past the house. Make a level mark out to the back of your fascia on the top of each 2x and string a chalk line across those two lines from one side to the next.Now run all your 2x's along side the rafters by putting a nail in at the plate line with the rafter flush at the top and then at the mason line slide the rafter until it hits the line and then nail the rest of the rafter off.Once your done with that take the marks you already have at the top of each end rafters and plumb them down and mark the bottoms of each rafter. When your done with that just snap the chalk line at the top and remove it and cut the two end plumcuts and make a small 2x block pattern with the plumbcut on by scribing it on one end and tack a piece of plywood on top and then scribe all your plumbcuts with that using the chalk line you snapped as your guide.Once your done with that measure down your desired height for the fascia plumbcut/soffit level cut and snap a line and then square those lines in and make your level cuts. Now you can run your nailer on the house and then your level soffit 2x's along side the new rafters.I hope this makes sense to you.Joe Carola
Edited 10/12/2005 11:44 pm ET by Framer
Sicillian, you have the luxury of determining your own plumb and level cuts. You can put them wherever you want them.
I think it might be best for you to draw a picture of your entire soffit system in full scale. Drawing the overhang in full scale has helped every single rookie that I've ever met.
Do you know what the pitch of your roof is? Do you know how to figure out what it is?
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