Building sofits/ extending rafters

[Umby]

Yes I could mimick the bird mouth and create a template. But I fear variations in the other rafters may cause my tails on the outside go 'up and down' with respect to each other. I'm not concern with length outside, I can just over extend and rectify with a chalk line. However your taught string idea may still come in handy. I'll install the first and last tails and then tack a taught string accross the tops of them. Then as I go to install the remaining tails, I'll adjust them 'up' to meet the string and nail into place and plum trim (with my new toys!). Does this sound like it would work?
Thanks for all of the help, this project will occurr during the week of 23JUL - 31JUL, and I don't think I could prepare enough. I would like to send/post the sequence of steps (about 30 of them) that I would take to achieve this effort. Would you mind taking a look at them and warn me of any out-of-sequence nightmares I could cause myself? Thanks again Cap'n for all of the help.

[mrcaptainbob]

That's a great idea using the string to keep it all level. Hopefully the roof is such that you'll be able to do that. I agree with the preparation. Always was a believer in gettin' the ducks in order. Glad to help. I'd like to see the 30 steps. Sounds like a plan-in-progress...

[Umby]

Here's the sequence I think it should be done, but please note the questions along the way and thanks again.
1. Have tarps ready...
2. Tear off gutters and drip edge (carefully for reuse)
3. Remove top two tiers of aluminum siding
4. Cut third tier in half long-wise leaving makeshift tabs to re-secure with nails
5. (or not? I may just install the nailer to this third tier of siding...?)
6. Remove old facia board (or whatever exists) to expose the rafters, pull back insulation inside attic
7. Measure existing rafters for their bird mouth dimensions and create a template
8. Cut and sister-in two new rafter tails to the existing rafters at both ends of the sofit with (say) 2' overhang
9. (Rafter tails inside the attic around 5')
10. Cut and sister-in all of the rest of the rafter tails with a greater than 2' overhang
11. (Use taught string ran between, and on top of, the first and last rafter to align the remaining rafters)
12. (What about old roofing nails keeping me from getting the two rafters to align?)
13. Snap a chalk line fastened between, and on top of, the ends of the first and last rafter tails
14. Plum cut all rafter tails (with my new trim saw!)
15. Push insulation in attic back into place and insert new air dams in between rafters from outside
16. Nail 2x4 (or 2x6) sub-facia accross the rafter ends flush with their bottoms
17. Level measure from bottom of sub-facia to wall at both ends of soffit and mark on wall
18. Snap a chalk line between these two marks
19. Horzontally nail up 2x4 nailers to the wall with their bottom edge flush with the chalk line
20. At every rafter, measure and cut 2x4 lookouts to be toe-nailed to the nailer and nailed to the rafter tails
21. Nail on 1x6 facia board, possibly vinyl, but certaininly painted or treated, to the sub-facia
22. (Carefull placement of the facia to allow for sheathing to clear and overhang a little)
23. Measure, cut and nail-on, plywood sheathing to the tops of the rafter tails
24. (Maybe I should use the entire 4' width of the new piece and cut up 2' into the old roof ???)
25. (How much sheathing should overhang the final facia piece?)
26. Cut and nail on, a plywood triangle to the vertical end of the soffit, cover with piece of siding
27. (What would this piece of siding be called? (It comes down the gable and stops with the original roof))
28. Nail on L-channel facia piece (will this cover the entire facia?)
29. Measure and nail on F-channel to wall, on or just beneath the nailer, horizontally level with the L-channel
30. Measure and cut soffit pieces, snap into place between L and F-channels
31. (Should I bother with a rubber-like ice shield at this point? (I don't have one on the original roof))
32. (I'm sure it's code in southeast MI for a new roof, but this project is just an extension)
33. Tack builders felt onto sheathing
34. Nail on drip edge and shingles
35. Nail up gutters
36. Cut and put in a ridge vent who's square area is equal to, or just less then that of the new soffits' sq. area
37. Drink a cold, cold beer

[mrcaptainbob]

I just came on for a few minutes tonight. I'll print this and 'digest' it. Most of it sounds good. Although, you went WAAAY over the estimate of 30 steps!! I was thinkin' about the rofing nails giving you grief, too....Will talk with you tomorrow....

[Umby]

Yes, it's a bit long winded, so take your time in replying.

I'm thinking about cutting back the existing sheathing to expose the older rafters to a depth, equal to that of, the new extensions' inside lengths. Understand?

This would solve several problems:
1. the dreaded old roofing nails hindering the inside rafter alignment
2. give me room to nail
3. I could work outside of the house instead of in a 160-degree attic
4. because I will be alone for most (if not all) of this project, I could see the rafter-tail alignment on the outside while nailing inside the attic
5. I could make a smaller bird mouth increasing the soffit sq. area and strengthing the overhang
6. and as a result, I would be cutting out and replacing the bad sheathing caused by the ice dams
(I love lists)
Regarding #5, this could cause a slightly different pitch where the two decks come together, but I don't think it would look unsightly or cause problems.
Some more for you to digest!

[mrcaptainbob]

Well, ambitious...yes, but I think it's the right way to go. I like that idea of removing the decking, especially if it's been damaged. You're right about it opening up the opportunities...The ice dam is a definate requirement here in Michigan. (I'm in Jackson County, was Wayne..) That's a really good plan. THe only places that I would comment on are (from 1st list):
16. Make them flush with the tops of the rafters so as to not kick up the decking. You alluded to that in your 2nd list.
19 and 20 are not necessary. I would think the lookouts would be more a structural need if the overhang were greater than 2 foot.
21. Yes, vinyl is the way to go for this. Very easy to work with and FAR more forgiving than aluminum!
27. Good question. (this means...no answer!)
28. Nail a J channel to the underside of the soffit so that the bottom of the J is against the inside of the facia board and that the short stem of the J is even with the bottom of the facia. The F should then be placed on the wall directly across from that J and the two will provide the parallel channels for your soffit trim.
I prefer to use aluminum for the soffit panels, vinyl for all else. I've had trouble finding vinyl panels with holes punched small enough to keep out the Lady bug type beetles, mosquito's and a few others. The aluminum has a finer brether hole opening that helps keep out these critters. To help your cutting, get a good 2x12x14'. nail some 2x4 to the edges to create a channel. About midpoint build a bridge across that's wide enough for your saw and saw guide. Make sure the guide is 90 to the side rails. Run your saw through the piece and just about an 1/8" into the 2x12. Now you have a nice true saw guide to use for your trim pieces. Reverse the blade in your skilsaw. Use it that way for the vinyl as well as the aluminum. When placing the siding on the house verify where you want the overlaps. They should always be flowing away from the line of sight. Nail up the first piece furthest from the normal approach to that wall of the house. Don't drive the nails hard. The siding needs to float under the fastenrs. Vinyl and aluminum both have a terrific rate of expansion. I don't believe you can over vent the attic. if you use the perforated soffit the entire length would be fine. The ridge vent is a great idea. For the ease of it, just go ahead and do the entire ridge. (this is an opinion....I run the ridge vents right to the roof edge and use the cap ends to seal it. I think it looks much nicer than stopping 2 or 3 feet shy and shingling a slope to the normal roof ridge. My $0.02.)
Are you going to reroof the entire house at this point? Or just the edges you're working on. Would it be possible to do two strips of that ice dam? (By the way, rent a roofing power nailer.)
Get that cold, cold beer.

[Umby]

No lookouts? that would save me a lot of work.
As for re-roofing the entire, I probably should, but I only intend to the eaves and a couple of feet up. I will definately cover the entire project area with that ice shield. How wide is that stuff?
I followed saw guide but got lost at the bridge. Maybe run that past me again. I have a DeWalt chop saw, circular saw, and jigsaw. I guess I will have to use the jigsaw to cut the bird mouths unless you can think of a better way?

[Umby]

Cap'n, this is where I got lost:

[mrcaptainbob]

Great pic! Yep...that's it. Screw a saw plate guide to that. Make sure the guide is 90 to the side rails. The first pass with the saw will trim off the excess of the bridge and make it true also, plus, by passing through the two 2x4's, you'll have excellant guides to set the marked siding pieces. I believe the ice dam is 36". Roll it out the length of the roof. It's plastic backed on the adhesive. Run a nail at the upper corner when you have that in position, then run a nail in the far upper corner. Fold it back long-wise and peel that plastic off and set that half down to the wood. Once it touches, it's there forever! Extra hands would be nice for this part! Yeah, the birdsmouth does make it necessary to use a jigsaw. Still better than handsawing!! Sounds like you're on your way!

[Umby]

Sorry cap'n, it must be me, but I'm not following how this device works. When you say "screw a saw plate guide to that", are you referring to a part on my cicular saw? Does the bridge have to fit in between the 2x4 rails or on top of them? And what does this eight-inch cut go into?