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I’m about to have a large residence reroofed. The existing roof consist of a ventilated space above the insulation between the roof joist, a layer of ply. sheathing, a layer of a material similar to Grace ( the roof is about 15 years old) with the shake shingles mounted on 2x’s so that there is a breather space and it acts as a cold roof. In obtaining bids I have had two very different concepts presented to me.
1. Tear off the shingles, mount a layer of 7/16″ ply on the 1x’s, cover the whole thing with Grace and mount the wood shakes directly on that surface.
2. Tear off the shingles and install new ones directly on the 1x’s again.
The difference in concepts is primarily that the shingles must ( or must not) breath to prevent cupping. Oh ya, I forgot to mention that the location is in the mountains of Colorado ( very dry and a lot of snow).
So, the question is, what is the correct philosphy?
Replies
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Buck, As a professional Roofer, I've done it both ways.The non-vented shingles nailed directly to the sheathing cupped like crazy and had to be replaced in five years. Proper venting is a MUST! There is a couple of products on the market to allow venting without the traditional furring strips. Ben Obdyke makes "Cedar Breather", it allows direct nailing, it's fast, easy, and it works. Make sure to follow their eaves and ridge venting details. Also, make sure the shingles are spaced at least 1/8", more if they are wet at time of application, and only two nails per shingle. Good luck! Check out Ben's website at: http://www.obdyke.com/cbindex.htm
*Buck, I'm not surte what you mean by Grace, must be a regional term.Bruce is right, this stuff's gotta breath: politely show roofer 1 to the door, saying a silent prayer all of the way you didn't buy into his cockamamie scheme.("But that's the way we do all roofs: solid decking is required!" Wrong - just for asphalt/fiberglass shingles)
*Bob, this is likely Ice and Watershield, made by Grace. Doesn't breathe at all.Hi, Buck, glad you made it over here!
*Roofer two got it right . Its that or the cedar breather. Over slats is the best job. Some say, including my salesmen. That you can install hand splits on sheathing because they are so bumpy that they can breath on there own. I don't buy it, slats all the way.
*b WBA At Your Service Am I missing something here ? If the old cedar shake roof was done properly, and it sounds like it was, then why did it only last 15 years ?
*Buck, My original posting got lost in the weekend purge. I agree with the skip sheathing as the best choice, but the cedar bureau now will accept plywood solid sheathing if required by local codes. They do not addrtess the longevity of applied shakes however.check out http://www.cedarbureau.org they have an excellent informative site including installation for shakes and shingles. Each has seperate requirements for underlay paper.walk gooddavid
*Tim - I just moved to Denver from Canada and all the roofs in our 20 year old neighbourhood have to be replaced. Cedar shake over tar paper over plywood. No skip sheathing or strapping. Surprise, surprise their rotting. Secondly, they installed the shakes the way you're suppose to install cedar shingles - another no,no.
*Forgive me if I missed something, but you are putting cedar shake shingles on a roof in the mountains of Colorado? I know our county doesn't allow it, but I guess some still do. Aren't you putting your house in danger with real wood shingles? Weren't the fires of last summer enough to scare the crap out of anyone living in the mountains? I'm not trying to sound condescending and maybe I'm confused. Just wondering.
*Ah...but the covenants of many subdivisions in Denver REQUIRE shakes. Plus, contrary to popular belief Denver isn't in the mountains. It is in the prairie on the edge of the mountains. So, most of the metro area doesn't have the same fire hazard the folks do just a few miles away.Not promoting shakes, just explaining.Now for the original post: I wouldn't use shakes anywhere it wasn't required. They are too much of a fire hazard, they are too fragile, and they are too expensive. Several homeowners I know even have to pay extra insurance premiums because they have shake roofs. My advise is to find something else to cover your house with.
*Okay, so I did understand correctly, it is wood shingles. The original poster, Buck, stated that he is in the mountains, not Denver. In my Colorado mountain county (Gilpin), wood shingles are NOT allowed. Maybe I'm just paranoid. We even made sure our chinking between our logs has a 1 hour fire rating just to be safe (probably a gimmick, but what the hey). Buck, perhaps you want to reconsider? We came home on Sunday to about 5 tankers, 12 sheriffs and 4 firetrucks in front of our cabin. The cabin next door caught fire. Thank the lord it wasn't windy and things are still wet. YIKES! I'm with FredB. Find something else. Not trying to tell you what to do, just offering my paranoid point of view. Good luck whatever you do and enjoy this most glorious (and oh-so-short) time of year.
*if you have to use wood shingles... (not shakes ).. you can get factory treated fire rated ...also... i wouldn't go along with the cedar bureau about wood roofs on plywood....guaranteed for premautre failure...either skip sheath.... or cedar breather....
*Mike, In reading the cedar bureau installation guidelines, the stated solid sheathing would be acceptable only if required by local codes. They still want to sell shigles/shakes. I agree skip sheathing is the way to go; and if you need to replace your roof in fifteen years, because it is installed over solid sheathing, as long as it is with shingles/shakes....There are several cedar shake manufactores that offer lifetime class A fire retardant shakes. To my knowledge after some research this spring on the subject, there are no long-term topical fire-retardants . Keeping your roof shingles/shakes from drying out by keeping them oiled will help in fire protection.walk gooddavid
*Okay guys, here's the skinney concerning fires and wood roofs. I live on Flagstaff Mountain.........yes the place where the fire was last summer. After watching the fire for 2 1/2 days I was forced to evacuate at about 6:00 PM Sunday night. At the time we evacuated this was the situation: - We were about 200 yds from the fire - We were up-hill from the fire - We were down wind from the fire - The fire was spread out in a line about 300 yds. long - The tips of the flames were about 150 feet above the ground - The fire was totally out of controlNow in these circumstances, I don't care what roof you have on the house, when the fire gets within a 100 ft. of the house the house is probably going to explode. I watched the fire jump a meadow that was about 150 yds. wide in about 2 seconds. The grass never burned, the trees on the other side simply exploded and the fire moved on.I have lived in the mountains, this location, for over 27 years and fire is one of the hazzards that you live with. You take precautions but you don't necessarily design your house to be fireproof.By the way, right after we evacuated, the wind changed direction 180 degrees and the fire burned back on itself and they brought it under control. The fire never reached my property.The house of which I am overseeing the reroofing is located within the city limits of Aspen.
*David: "Keeping your roof shingles/shakes from drying out by keeping them oiled will help in fire protection."Don't believe it. If you want the lowdown on wildfire contact BLM or USFS. They have great pamplets on how to protect your house from wildfire. But, as Buck says you can only do so much. But, that "so much" will include NOT having a combustible roof and clearing for a l-o-n-g ways around the house.
*Fred, Shakes/shingles present such an enormous fire hazard especially when they are dry and brittle. In the West, this can occur even after one or two summer seasons. Most people do not bother with keeping their wood roof maintained which in the dry west means keeping them well oiled. It will not prevent a fire from starting but it will slow the ignition time over dry shingles. If my early posting was misleading, I apologize.walk gooddavid
*david:You toofred
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I'm about to have a large residence reroofed. The existing roof consist of a ventilated space above the insulation between the roof joist, a layer of ply. sheathing, a layer of a material similar to Grace ( the roof is about 15 years old) with the shake shingles mounted on 2x's so that there is a breather space and it acts as a cold roof. In obtaining bids I have had two very different concepts presented to me.
1. Tear off the shingles, mount a layer of 7/16" ply on the 1x's, cover the whole thing with Grace and mount the wood shakes directly on that surface.
2. Tear off the shingles and install new ones directly on the 1x's again.
The difference in concepts is primarily that the shingles must ( or must not) breath to prevent cupping. Oh ya, I forgot to mention that the location is in the mountains of Colorado ( very dry and a lot of snow).
So, the question is, what is the correct philosphy?