I am working on a Craftsman sytle home for my growing family and have hired architects for the design work. The initial design included exposed rafter tails. When I showed the design to my framer, he said as long as the rafter tails would be exposed, they would need to be pressure-treated (PT). So, unless I’m willing to scab on some PT tails to the end of a conventional rafter, I would need to use PT for the entire rafter, which is prohibitively expensive. My architects are insistent that this look is needed “to preserve the Craftsman integrity of the house.” Right now I’m more interested in preserving the integrity of my budget
This leads to the following questions:
1. If the tails are only partially exposed, can I get away without PT? The original design had the tails extend past the roof decking, but the latest version extends the decking so that the tails are actually protected under the roof, but still open and visible. Does this eliminate the need for PT tails?
2. Assuming I can figure out how to finish the rafter tails, I’m still not sure of how to trim them. I was thinking maybe some beadboard betwween the rafters, but I’m still not sure about this. My wife thinks I have a unhealthy fascination with beadboard.
3. Does anyone have an easy design for an eave detail with exposed rafters? Surely I’m not the first person to face this problem, but I can’t seem to locate any design advice.
Thanks.
Replies
I use 2x6's doug fir for the tails holding the the top of the 2x6 down 3/4" from the top of the 2x8 which allows for 1x6 T&G to be exposed. So the top of the T&G is flush to the top of the 2x8 rafter. Now you can nail your sheathing on top of that. We use 5/8" sheathing which gives you 1-3/8" of material to nail your shingles up without the roofing nails popping through but 1/2" sheathing will work also with 1-1/4" roofing nails.
If your using a 2x8 or 2x10 rafter, you can rip down the top 3/4" and rip the bottom of the tails so that they're a 2x6 width.
Here's a drawing.
Can you tell us how you fill in between rafters/rafter tails? I have my addition framed with scabbed on rafter tails, t&g, and 5/8" ply on top. I wasn't sure of an easy infill between so I put solid blocking on top of the wall framing between rafters up to within 1" of the bottom of the t&g and was planning on using cor-a-vent RS400 for venting but may have been talked into using screen instead (I can elaborate). To trim it out I have 1x trim that I guess has to be notched at each rafter tail to cover this up. Is there a better idea?
Thanks,
Greg
Hi Greg T
Don't confuse me with one of the experts, but this is how I trimmed out my exposed rafters.It was pretty easy with just a few nailer blocks and cheap vent strips, which are readily available in our small town. Works like it should and doesn't look all that bad.
( Ok so I figured out how to add a photo, but how do I make it smaller?)
Oh, why are you not using the Cor-A Vent product?
Thanks for the photo and idea of using the louvred vents.
I made the mistake of thinking the cor-a-vent would be in stock at the local cor-a-vent distributor so I didn't order it. They say at least two weeks and I need to get this wrapped up this weekend. Also, and I don't know how much weight I put in this, a former distributor which is a very reputable lumberyard stopped handling their wares due to problems that the mfr wouldn't back up. Since there is no way of knowing what the problems were or in who's opinion they weren't backed up I don't know whether to believe if a legitimate concern should be had. I believe they have an excellent reputation.
Thanks again for the photo. That really helps.
Greg
I just had to order some Cor A vent this past week for another project, and they shipped it out the next day.
Do you order direct? My local distributor may not be very motivated but said it would take at least two weeks to get the model I needed. Just curious for when it comes up again.
Yes direct. You can find the # in the ad of any of the new FHB ( where I first found out about Cor A Vent), or go to their web site.
Feeling kinda dumb. I was led to believe that they will not sell direct to protect their distributors. I have to either pay more attention or ask questions.
Don't feel dumb. I live in the most remote county in the lower 48. Not too many places to shop so I end up ordering a lot of stuff . It never even occurred to me to ask if I had to go through a distributor and they never mentioned it.
You can use "Irfanview" to manipulate the images. Just download it and mess around with it -- it's very simple to learn.
View Image
thanks. I downloaded it, now I just need some time to mess around with it
Thanks to all for the good advice and photos.
There is something unnatural to me about scabbing on a rafter tail extension to give the look of an exposed rafter tail (although I suppose I should consider this simply another form of exterior trim, all of which is just nailed onto the exterior.) For that reason, I'm leaning toward extending the actual rafter, keeping it under roof, and protecting it properly.
As for the trim, since I'm using the actual rafter, I suppose I'm left with either ripping the end and laying beadboard flush with the top of the rafter, or simply nailing exterior rated beadboard over the extensions and roofing right over top of it. I'm leaning toward ripping the rafters.
I dont' expect to need the vents between the rafters because I'm planning an icynene insulation system that doesn't require vents (but I liked the discussion and photos anyway.)
I dont' expect to need the vents between the rafters because I'm planning an icynene insulation system that doesn't require vents
I almost mentioned spray foam as an option, but figured that train was probably well down the tracks by now.
We used icynene in our own house and are very happy with it.
1. If the tails are only partially exposed, can I get away without PT? The original design had the tails extend past the roof decking, but the latest version extends the decking so that the tails are actually protected under the roof, but still open and visible. Does this eliminate the need for PT tails?
Anytime that end grain is exposed to the air, it'll absorb available moisture and gradually decompose. Exposed rafter tails aren't a viable long term design feature for that reason.
As long as the rafter tails are protected from water running over them by the roof edge overhang, there is no reason for them to be PT. I have worked on homes over a hundred years old with exposed rafter tails that had no problems. They do need to be kept painted or otherwise finished.
For the finish. on mine, I use Pine V-groove T&G, then transitioned to ply.
Some places require a minimum penetration of roof nails, so the rafter tial is ripped to remove the thickness of your beadboard, so it is laid face down over the rafters, then the sheathing run over that right on up the roof.
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Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
"I have worked on homes over a hundred years old with exposed rafter tails that had no problems. They do need to be kept painted or otherwise finished." Piffin
See! Per the prediction in my previous Email, he took the bait and has volunteered to keep your rafter tails sealed for the next hundred years. ;-)
"where there's a will, there's a won't" HVC
I guess you don't use paint there, eh?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
We use the same detail as Framer and do the same up the gable ends. We run the 1x6 into the house one or two rafters to help support the barge rafter. After the roof sheathing is applied, the gable end is well supported and the barge rafter supports can be installed later with little concern.
Bruce
> When I showed the design to my framer, he said as long as the rafter
> tails would be exposed, they would need to be pressure-treated (PT).
In Atlanta? He's talking through his hat. Head down to the Midtown area. Drive around the area near Myrtle, 4th, etc. east of Piedmont. Note the exposed rafter tails on the bungalows. Those were put up in the 1920s and are southern yellow pine.
I'd be wary about running the rafter tails *beyond* the edge of the roof shingles. As long as you don't do that, you've got nothing to worry about --- as others have already stated, it's been a standard design element since the 1910s and has a proven track record of success. Just keep the end grain painted or otherwise sealed and you'll be fine.
Beadboard looks great -- don't let your wife talk you out of it! ;) Several people have suggested good approaches -- I like having "double sheathing" (ie plywood sheathing PLUS the beadboard) so nail penetration is not an issue. Keep in mind that you can also get exterior-rated beaded ply, which could work out to be less expensive than using individual T&G boards.
For what it's worth, I just had some exposed rafter tails replaced, along with other damaged wood during a re-roof. The house is 40 years old, and it turned out that only a handful needed replacement. With better maintenance, even that wouldn't have been necessary. The tails with the most rot and termite damage did not have fascia, ever. Also, no gutters. Of course, this is in CA, and I would say the house is well suited for our climate. All the wood work was done with DF/HF. I don't think PT is allowed here for this use--it certainly is not used. Also, disposing of green PT is getting to be a pain here due to landfill regs. Good luck.
he said as long as the rafter tails would be exposed, they would need to be pressure-treated
Huh? If the water travel (drip edge & similar details) is properly set uo, the exposed rafter ends really ought not get that wet (barring living on an exposed seacoast or the like).
"Needing" to be PT would be a new one to me.
Further, rafter tails, whether integral or sistered on, have been used on houses for what, a century or so? Typically they get painted, but I've seen others left "as is." Now, this is Texas, from here off to the west of me, it just gets drier and drier. Western cedar can be exposed, and it will go silver, and "play nice" just as is--IF, only if, the drip edges & trim properly get the rain, when it rains, off the roof and not on the rafter tails.