Hi All – I’m looking for some experienced opinions out there. I have a cape cod style home. I want to put a new roof on it. The shingle I want is the Certainteed Presidential TL (Triple Layer). It weighs 480lbs per square. My current roof is cedar shingle. The roof structure is 2x8s, on 16 inches centers. I don’t know the pitch. But it is very steep (see attached photo). My question is this…Can my roof handle the weight of this shingle?
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Replies
Where do you live? How much snow do you get every winter? Has the cedar roof failed/ started to leak?
I'm Dan Boyle, and I approve of this message.
I live just outside of Philadelphia. Generally not a lot of snow, but it can, and does, occasionally happen. But due to the steep pitch, not much seems to sit on the roof. I'm replacing the cedar because it is curling, splitting, and leaking.
idom
Outside philly eh?
1st of all, cedar curls and splits. That is normal. If this is a recent picture, your roof looks in awesome shape and might need some shakes repaired.
If your roof is on lathe (1x3 strips) and is well venitated, it should last 40+ years but will require some repairs.
Dont be buffalo'd by 1 roofer.
Get several opinions.
I fixed a roof in West Chester 2 years ago. Client wanted to get 5 more years out of it and they will after the repairs even though the roof is old, soft and really in rough shape. (it is cedar and lasts a long long time)
Requires the right contractor not trying to get a new roof out of the deal.
With that said, if the roof is in bad shape then so be it. Time to replace.
460 lbs per sqare is only 4.6 lbs per square foot which is not too much. Most homes are designed for 10 lbs dead load and 30+ of live load (wind, snow, etc)
My sense is that you are fine with the replacement.
Jeff in PA
>>>>>>>>If your roof is on lathe (1x3 strips) and is well venitated, it should last 40+ years but will require some repairs.Not necessarily. Years ago, you'd be right. Lately, the cedar I'm seeing has wide growth rings and is not as long lasting. I've got one that's 2o years old that I see regularly. If it makes it another five years, I'll be surprised.View Image
Hmm
I am not surprised that the newer shakes are not lasting as slong as the quality of most lumber has wained in the last 20+ years.
I am sure money can buy good shakes but at what cost?
Most of what I have ever messed with was old stuff that could last a few more years though was in rough shape.
Thanks for the info
>>>>>>>>I am sure money can buy good shakes but at what cost?From where? The good stuff was old growth vs the newer stuff which is basically farmed and encouraged to grow quicker resulting in wider growth rings.View Image
Old growth shake blocks are still very common here. They cut them from scrap left on remote cutblocks and when they assemble enough, fly them out by helicopter.
Still not my favorite roof. Nasty to walk on, no guarantee of consistent wear and certainly no warranty.
Old growth shake blocks are still very common here.
How do I buy cedar shingles made from them? Most of the cedar shingles and shakes I've seen lately are coming from western Canada. And they've got wiiiiide growth rings. View Image
I should have added that although still common, old growth shake blocks are like gold. They mainly go to specialty mills or are exported. There is a huge black market with people stealing shake blocks. You can not transport them without displaying a large permit on your truck and the police sometimes set up roadblocks to catch thieves.
Somewhere there are still old growth trees standing, I am guessing. I dont know the life cycle of cedars but I am guessing that they are out there.
rc roofs are only lasting 20 years here....even on skip-sheathing'''
we started using "thick butts" to get more life,........and
we'll only install on skip-sheathing or cedar breather
rc just is not....is not... the same material it was ... and it no longer lasts as long as it used toMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Hmm.
For the price, that is hard to justify. I presumed that on lathe (skip sheathing) that you would get a longer life out of it.
A lot of the newer stuff around here (until 3-4 years ago) was installed on osb so it was not lasting long at all (15 years maybe) and I figured it was all due to the lack of breathing due to the osb.
guess that was part of it but not the whole picture.
What I'm seeing here is 12-15 years on solid sheathing and 18-20 on split sheathing. But, to qualify that some: For the most part, the split sheathing jobs have been better installed.View Image
Do you see a longevity difference between shake on skip, versus shingle on skip?
View Image
"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Do you see a longevity difference between shake on skip, versus shingle on skip?
We don't have a whole lot of shake around here and from what I've seen, the snow baffle (felt) is installed wrong more often than not and traps the moisture in the shakes. They install it too low (where it's visible between shakes).View Image
seeyou,
Wow, I must be really lucky because all the cedar I've seen (even at Home Depot) is really tight grained, old growth stuff.
Spendy but nice tight old growth stuff.
all the cedar I've seen (even at Home Depot) is really tight grained, old growth stuff.
Home Depots here wouldn't know a cedar shingle if it was wearing a name tag - old growth or new.
We can't hardly even get them from lumber yards anymore. They're special order so you can't see them before you buy them. View Image
Hmm See you We have em at home depot, and most of the roofing suppliers carry several different sizes and styles. Regional thing I am sure.
that photo is too big for me. Any chance you can repost it under 200KB?
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Here you go Piffin.
Joe Carola
hey piffin
That was not my photo and even if it was, I would not know how to reduce the size
I dont know if you sent the request to the OP or not, I just know that you sent to me
I knew that. I had adressed to you because you were mentioning specific conditions seen in the photo, but I guess it doesn't show thru in the downsized version.Didn't realized you had limited photo manipulation skills.
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re. photo hypersensitivity
Like a car, I can crash them no problem, but to get em to run right, forget it!!
Can my roof handle the weight of this shingle?
Yes.
View Image
Can you tell us the thickness of your sheathing, and whether it is plywood or OSB?
In your latitude and climate, a lot of 1/2-inch gets used, but it may be thicker on your house.
Your new shingles will bring a nominal 6.9 pounds per square foot of dead load to your roof. I took your roof to be a 12-pitch.
View Image
"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Gene - Right now, the cedar shingles are nailed directly onto purlins (I think that's what they're called). But the roofer is proposing 7/8 OSB, which will be nailed over the purlins.
Are you sure he said 7/8ths, and not 3/8ths?
Probably said 7/16. Never seen 7/8 OSB on a roof.
To answer the question, I go along with grant, do it!
I've always heard the strips called 'skip sheathing' 1x3 spaced say 2-8inches to nail shingles to. Once you install continuous sheathing, you likely pick up a lot of structural capacity and stability. Roofer should consult w/ the BO re: this to make sure the BO buys off on the sheathing and your choice of shingle.
no...they are not purlins...your roof is skip-sheathed...
your roofer is proposing to strip the shingles, install 7/16 osb over the skip-sheathing
and then the TL'S....right ?
(edit for 7/16)
no problem with the weight
Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Edited 9/14/2008 7:44 pm ET by MikeSmith
"nominal 6.9 pounds per square foot "Where do you get that from?His shingles are only about 75% of what you say, and he is removing the old cedar roof which weighs far more than the nails and tarpaper that get added top the shingle load, especially when wet!But I agree with the main point of your Q - that the sheathing condition is important. Would be a shame to add heavy expensive archies and see sags between rafters!
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It's from trigonometry, son. The black science of triangles.
Shingle weights are given in pounds per square of coverage, but us structural engineers like to think of roof loads as projecting plumb. Think rafter spans. It ain't the length, it's the span.
I said that I took the pitch to be a 12, thus the factor one would apply, and I did, was the square root of two.
View Image
"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Thanks Grand-Dad!;)I guess I don't have an opine on the length of service left in that one from what I can see here.Thanks frammer.
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More information is needed.
how wide are the kneewalls apart?
How wide is your bottom floor walls apart?
Describe your floor system that is carrying the knee walls.
Can my roof handle the weight of this shingle?
Of course it can. I've never heard of rafters being designed so that they can handle asphalt roof shingles. Rafters are designed to handle slate roofs though.