An upcoming project has 2×12 rafters at 12:12. The tails are to be 2×6 and projecting 2 feet. No soffit or boxing in, just the underside of the sheathing showing.
From the drawings it appears that the designer wants the 2x12s to project, but he wants the projecting sections ripped down past the blocking. I suppose I can do that… some careful work with a skilsaw and rip guide, some finishing with a handsaw.
I have seen another detail where a chunk of 2×4 or 2×6 is scabbed onto the side of each rafter, and that’s what shows.
How do you do this?
Edited 11/25/2005 11:54 pm by davidmeiland
Replies
I'd order some higher quality 2x6, suitable for finish grade paint and scab them on.
blue
OK, so I'm trying to figure out the blocking detail. Either (1) the 2x12s are plumb-cut at the face of the wall, and I need to block between them, or (2) the 2x12s are plumb cut 1-1/2" back from the face of the wall and I run a 'rim' around. Either way the 2x6 coming thru creates a 'notch' that has to be cut thru the blocking.
The building in question is a small barn-looking shop. Vertical resawn board and batten siding, a metal roof. It is replacing an absolutely utilitarian pole barn.
This drawing is with the tails dropped 3/4" because t&g will be on top and then the sheathing goes on top of that, but in your case you just keep the 2x6's flush to the top of the 2x12.Joe Carola
Either way you'd want the 2x12 set back so the blocking hides the end joist of the rafter. You would do that if you ripped the 2x12 down wouldn't you?
On second thought: why wouldn't the siding continue all the way up to the bottom of the scabbed tails?
I'm not familiar with exposed rafter detailing but I wouldn't want a 2x12 block at the top of my wall. I'd set my rafters flush with the framing and run my sheathing up onto the plumb cut. I'd then block inbetween the 2x6's with 2x6 blocks- no notches necessary.
blue
"I'm not familiar with exposed rafter detailing but I wouldn't want a 2x12 block at the top of my wall. I'd set my rafters flush with the framing and run my sheathing up onto the plumb cut. I'd then block inbetween the 2x6's with 2x6 blocks- no notches necessary."You have to notch the blocks with screen behind them so that you can vent the bays.Joe Carola
something like this... it does seem like the blocking between the 2x12s would need to be notched around the 2x6s. That blocking would not be visible.
forgot the pic
Use Cor-A-Vent's S-400 strip vent, cut your 2x blocking so that a 1-1/2 space is allowed for the strip, and nail them to the tops of the blocks. Easy as pie.
The black Cor-A-Vent looks like black screening or honeycomb. Practically invisible up there in the shadows, especially if the finish of the blocking and frieze is dark.
Well, I hope Huck doesn't mind...i took his bitmap and added a few things...
You could do it like the first one, which is easier. make sure you block as you go, or your rafters won't be perfectly plumb, leaving you a painful in filling detail of off by 1 degree cuts later!
The first view shows the venting on the top of the blocking, and second is the way I did it recently. The green is a top stop trim peice, teh red is sheathing and the T&G roof decking (I would lower your scab by the T&G thickness as mentioned above and overrun the ply roof sheathing for easier nailing), and the blue is the venting material. You could use the other stuff too if you had to, if the Cor a Vent isn't availale to you.Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
something like this?
View Image
Thats what I was thinking Huck.
In my 3 decades of framing houses, I've never framed anything with exposed rafters or tails.
blue
I have done this. Will there be anything blocking the view up the bay?
Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
There is to be screened blocking in each rafter bay, then FG insulation with space above for flow thru to a ridge vent.
That is a very common detail around here. Open soffits are the norm and most roofs are truss so you see 2x4.
We used to rip tails for 2x6 and use 2x6 birdblocks. That is a hassle and a pain when you gang cut the roof, but we did it for a long time. We use a 12" speed square to srcibe the 5 1/2" because you can stick your pencil in the notch. Its not difficult to rip a straight line with a wormdrive because you are inline directly behind the saw. I wouldn't mess with a guide.
We block right at the intersection of the rip with the birdmouth. When you install the sheathing and then the siding (if you sheathe while the wall is flat, I suggest running your sheathing higher than the plate) it will seal off any gaps.
Here is a pic from a year and a half ago. We ripped the tails 6 1/2" so we didn't have to rip our blocking and we added 1" Cor-A-Vent screens for ventilation.
http://pic9.picturetrail.com/VOL293/2163851/4419028/88311201.jpg
The way I layout roofs like this is to figure your heelstand or HAP based on a seatcut that you want. I usually am around 3", but I might go 5.5" for the 2x12s. http://pic9.picturetrail.com/VOL293/2163851/7154567/119988779.jpg
For our overhang sheathing, we use LP Soffit. http://lpcorp.com/lpsidingproducts/lpsmartside/products/soffit.aspx
Of course, I scred up the first diagram upload. It shows the venting at the top.
I can shoot pics of the finished detail as I will be back there tomorrow, if you like.
Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
ok, HERE is the file, LOL.
Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
Thank you gentlemen. It seems like there is a fairly consistent approach to this, except in MI where 100% of soffits are boxed in (I can think of at least 10 houses there owned by friends and family and it's true, they all are).
I'm leaning toward ripping the ends of the rafters down so they can project, rather than scabbing. The main reason being that I can more easily get the layout I want on the exposed tails, rather than dealing with 1-1/2" offsets everywhere.
Some of these tails project right out over windows and it will be easy to see the undersides of the tails and whether or not they are cleanly ripped.
I'll have many more questions about this project. It's my own shop, replacing an old leaner dirt floor pole barn. One of my main goals is to pre-plan the framing and sheathing so the entire thing can be up in two days. I've done some labor trading with other guys here and will be able to get 5 or 6 skilled bodies for 2 solid days. I'll try to get a couple of the elevations posted.
What size roofing nails will you use?Joe Carola
Metal roof, no nails
I believe the blocks directly on top of the wall cap plate are called freeze blocks and it is my impression that it is a somewhat common detail in the NE USA. (I don't live in the NE USA). To me, I see very little reason for it and think that it just makes it so that the ceiling/roof insulation doesn't fully cover the cap plate.
I say just run your sheathing all the way up, like was suggested above, and block between your 2x6 tails only like Tim showed in the drawing: http://pic9.picturetrail.com/VOL293/2163851/7154567/119988779.jpg - and add your vents.
Edited 11/26/2005 8:38 pm ET by Matt
I'm pretty sure the 'spector is going to want blocking along the top of the wall, probably most of the height of the rafters. I don't think he'll go for just blocking between the tails, outboard of the wall line. We shall see.
Definately not required and rarely seen here in the NC. Same with SC and VA.
I'm pretty sure the 'spector is going to want blocking along the top of the wall, probably most of the height of the rafters. I don't think he'll go for just blocking between the tails, outboard of the wall line. We shall see.
The inspectors around here (in seismic country) don't require anything more than the birdblocks unless the engineer spec'd something different. All thats required is that that rafters have blocking and the birdblocks count. I would ask the inspector before you start.
Are you in an area that has special requirements for wind or earthquakes?
Blocks gotta go down to the top plate.
Boundry nailing is nailed into them gosh darn blocks from above.
TRIGGER
Since the beef of the rafter is critical t'wards the center of of the rafter. and you nail the crap out of the joist to said rafter to form triangulation. Wouldn't'nt you then be able to cut the birds mouth way deep?
I did mine that way, ripping 2 x 12s to the final size. Not that hard!Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
If you go the scab route, be sure the scabs have plenty of scab length, and are well-anchored. Nothing looks worse than sagging eves. (Well, OK, there are things that look worse, but nothing you'd want your name associated with.)
happy?
Consider spacing. If rafters are centered on 16s, a tail at every rafter will look too dense. A tail on every other one, placing tails at 32-inch centers, will look better.
Are you decorating the tail ends with an ogee or radius cut? It'll only take an extra hour or two.
"Consider spacing. If rafters are centered on 16s, a tail at every rafter will look too dense. A tail on every other one, placing tails at 32-inch centers, will look better."How do you nail sheathing 32" oc? Her said the sheathing is exposed.Joe Carola
He has a metal roof, and I presumed 2x4 purlins would be used, and no sheathing.
"An upcoming project has 2x12 rafters at 12:12. The tails are to be 2x6 and projecting 2 feet. No soffit or boxing in, just the underside of the sheathing showing."That's David's first sentence.Joe Carola
He could use your detail with 2x6 tongue and groove.
"He could use your detail with 2x6 tongue and groove."I've always done it that way. I've never done it where just the sheathing was showing. Eevry time I ripped the rafter tails down was because the soffits were going to be cathedral. I've done that many times.Joe Carola
Edited 11/27/2005 1:03 pm ET by Framer
What happens sometimes depending on the size of the rafter and the pitch is that you loose the heel of the birdsmouth when you rip the overhang down to a 2x6. If you have a cathedral ceiling I notch 1-1/2" up on the birdsmouth and add another top plate so that it doesn't lower or change anything on the rafter and it gives you a heel on the inside of the rafter.Joe Carola
If he were to use the detail someone showed with 1x? T&G showing from the bottom and the regular 7/16 sheating covering over the top, I think it would work fine with the exposed tails at 32" OC. Probably use something like 1" med crown staples to fasten the top sheathing to the T&G with regular fasteners in the 2x6 tails - and be very liberal with the usage of the 1" staples.
This is the way I always do it with t&g. Which gives you 1-3/8" to nail with. But I've never framed any rafter 24" oc or 32" oc. Even with 1-3/8" of t&g and 5/8" sheathing, 32" is still a lot of space unless you used 2x6 t&g. Then your fine.Joe Carola
You make great drawings Joe. Don't mean to be bad, but could the 2x8 be a different color than the 2x6 to further clarify?
"You make great drawings Joe. Don't mean to be bad, but could the 2x8 be a different color than the 2x6 to further clarify?"Absolutely.Joe Carola
The rafters are 24" OC. I plan to 'tail' every one of them, and use 5/8x4 t&g for the exposed soffits, to go with my 5/8" CDX roof deck. That's typical here, although I guess I have seen people lay the plywood over the t&g too, by notching the top of the tail down accordingly.
The Cor-A-Vent sounds nifty. 99% of vents here are round aluminum pucks thru 2" holes in the bird blocks.
One elevation attached. Footprint is 24x32. The steep roof is 12:12 and the shed is 6:12 (there are identical sheds both sides). For some reason he did not show fascia so the rafter tails are visible. There will be fascia and gutters. The rollup door shown ain't happening, it will be a swinging pair of some sort.
forgot pic... again
>> Even with 1-3/8" of t&g and 5/8" sheathing, 32" is still a lot of space << Yea... you are probably right. Don't you think that 16" OC would look 'busy' though? Obviously I've never built a house with this detail... Stupid Q: When doing these open tails, do you normally still have a fascia board or not? We have 99.5% closed soffits here.
"When doing these open tails, do you normally still have a fascia board or not?"Yes, always a fascia board. One time I framed a house with no fascia board. They were always 16" centers except the one without the fascia. That was closer to 2' centers because the existing house was so I had to match that. So I put blocks in between the rafters and nailed the tails to them so I could follow the existing lay out.Joe Carola
BTW - yesterday I was at Lowes and saw they sell the Cora-vent (sp?) - or at least it was the Owens Corning version of it. Also, BTW - I'd be interested to see what the eaves look like when you are done - mainly because I'm interested about the spacing thing with respect to esthetics.