All
We are doing a reroof on a 1970’s ranch with a 5/12 hip roof.
I always recommend tearing off the old shingles. This roof had 2 layers of asphalt.
The previous roofers shingled around the old vents and flashings.
In the pictures you will see why that is not a good practice. 1st layer is already off.
Plywood was ok but everything downstream of the vent was wet.
If you have to shingle over, then buy new flashings.
Rich
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Replies
Looks like Dorothy's house in Kansas.
Forrest
I've done 4 (maybe 5 - I can't remember for sure) shingle overs in my career. That's exactly what has always bothered me about the concept. Unless you reflash everything, there will be water running between the layers. Nice documentation.
http://grantlogan.net
Who got Bo Diddley's money?
that is the reason I won't re-roof anything anymore. Sidewall flashing needs to be cleaned out and redone otherwise I can't guarantee it. Valleys are the same thing. I have found that re-roofs diminish the lifespan of the new product you are installing by almost half. My motto for a re-roof is that your new roof is only as good as the roof your covering up.
Dustin
It's my understanding that most co.'s shingles loose their warranty when used over old shingles. Re-roofing.
It's my understanding that most co.'s shingles loose their warranty when used over old shingles.
I went back and checked a couple of warranties and I can find no mention of that. If the prevailing building code allows layovers, then the shingle has to be warranted for that application.
All that being said, most shingle warranties aren't worth the paper they're printed on and it's been my experience that the second layer usually doesn't last as long.http://grantlogan.net
Who got Bo Diddley's money?
Grant- i agree with you RE: the value of shingle warranties--- but gotta disagree on the projected life span of a 2nd layer install.I have worked primarily the same neighborhood for 2o plus years-----many of the customers have been in their homes for genrations.
They know WHEN the last roof was done---and How much they paid---they will often bring out the statement to show me from 1975 or whatever.properly done-- i see no difference in longevity----improperly done-tear-off OR layover--well THEN all bets are off but hey--this is just a 12 block radius neighborhood--maybe it's different everywhere else???Best wishes,
(BTW---frost warning last week---90 plus effen degrees this week!!!!!)Stephen
properly done-- i see no difference in longevity----
That's the deal breaker. I seldom see any reflashing done with a layer and you get water running between layers as was shown in the first post and rots the top layer from below. So, unless I'm gonna reflash everything, I won't do a layover.http://grantlogan.net
Who got Bo Diddley's money?
we have a lot of roofs here--where we might have a single 4" WSF and 3 slant back roof vents to replace--along with a chimney to re-flash.
It would actually take us LONGER to NOT replace the WSF or the slant backs---so why not replace 'em-----and I LOVE chimney flashing---so of course THAT's getting done.
I used to do a lot more layovers--maybe 10-20% of the roofs we did were layovers. this year---we have done one last year----- i am not certain if we did any------no wait----we did one for a customer with 50 year certainteedsplus my own house(50 year elks)--so that would be 2 in all of last year.stephen
your understanding is incorrect.stephen
Its hard to believe there are so many "roofers" out there that dont know which side of the shingle should face up.
I'm be no means a roofer but I know that, so I stay off roofs. I cant believe some of the things i've seen though.
My favorite is a ridge vent with no soffit vents.
"My favorite is a ridge vent with no soffit vents."
Yea see that way too often - how retarded can ya get
Ive always striped the roof and Im glad I was taught to do it that way because 95% of the time the roof dosent appear to leak but in reality something needs to be replaced underneath
One of those ridge vent with no soffit we took apart needed so much work almost all the plywood was delaminating I assumed it was cooking itself and you could pull the plywood apart in layers, probaly less than 12 years old
I just remembered one house I did with my ex business partner. This guy was cheap, he would've reused the paint in the houses we worked on if he could (good part of why we dont work together anymore).
Anyway the last house we did together needed a roof (he was the roofer). He decides we dont need to strip the roof (my preference) were just gonna go over two layers.
By this time in the partnership i've had it with this guy so I say whatever and start layin shingles. The very next day I come to work (in the rain) and walk in to the kitchen and find a real steady drip.
When he finally showed up, I pointed at the drip and walked away.
I'm thinking most that add a ridge vent without changing out the soffits look at it as a better than nothing scenario
and liken it to the equivilancy of a gable vent when it's just that they don't want to spend the extra dollars on the soffits.
they be saying something akin too "Hey, it'll let out some of the heat. I mean it's gotta, right? Heat rises?"
Edited 6/7/2008 10:32 am ET by rez
Sometimes that is true, maybe 60% of the time.There are other times tho when the vacumn created by the top vent sucks conditioned air from the house up and into the attic, then out of the house after leaving condensed moisture behind in winter.But the thing with "roofers" and doing soffit vents is that too many are just shingle layers who ONLY think of things from the metal eave edge up to the ridge. Nothing else ever crosses their minds.Unless she is sunbathing in the backyard
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
The same ex-partner on a siding job.
"We'll add a gable vent for you".
Thank God I looked before I cut. The place he wanted to add the gable vent would have gone right into the master bedrooms vaulted ceiling.
They got what they paid for :)
I confess, I've done one shingle over in my life. When I was young and innocent. Never again. I too have witnessed the ills associated with that practice. On many repair jobs when I was a carpenter I had to deal with multiple layers of shingles. I think the worst case was 4 layers. Dampness underneath the layers, rotted out roof decks, and deformed shingles.
ted--- i am not interested in changing your mind on this( after all, what's in it for me, LOL :>)however---consider that the statistical sample of roofs you are basing your opinion on-were self selecting---that is they were problem roofsIf you are called in to do repairs---and the roof you encounter is multiple layers--naturally you develope a low opinion of the layoverhowever---you aren't encountering the MANY roofs done as layovers--that are problem free---BECAUSE they are problem free !doing mostly roofing--we do one layer tear-offs, 2 layer tear-offs, 3 layer tear-offsI encounter plenty of older roofs that had asphalt shingles layed over a layer of slate--and the asphalt shingles lasted 25 years plusbasically i see 'em all-when they have reached the end of their natural life----and at least here-- i don't see a difference in longevity between a proper layover-and a proper tear-off. Hey- i have seen new roofs-one layer, that were bad from the get-go,
roofs done as a single layer with shingles that lasted only 8-9 years and so on---but those were roofs that were improperly done--just as many layovers can be improperly done. Tearing the old roof off----is ZERO assurance that the new roof will be done properly, LOL.look at it this way,-if i meet 4 red heads over the years--and all four redheads punch me in the mouth---is it logical to assume that ALL red heads will punch me in the mouth?????
( well---red-headed roofers, maybe, LOL)Best wishes,
stephen
Stephen and All
As the OP I just wanted to show the consequences of not reflashing when doing a shingle over.
I am not opposed to shingling over. As for me I feel like it is settling for second best.
As the tear off person the second layer is always harder to tearoff than just 1 layer.
We just did one with 1x8 sheathing. Second layer was 4" reveal and double nailed. The nails held like someone had pounded them over from the underside. The house in the picture tore up well even thoughit was double nailed because they used 1/2" ply.
I have seen layovers that have a long life. But as a general rule I think it diminishes the life of the shingle.
I too have seen single layers last only 10-15 years. Most people in our area have owned their houses for many years.
If you are going to layover then you should follow the instructions and cut 2" off the bottom of the bottom course. Then your layers mate together better. (The top of your new shingle butts against the bottom of one of the upper rows of layer #1.) I know you already do that Stephen.
That is made more difficult with trying to lay metric shingles(5 5/8" reveal) over old 3 tabs( 5" reveal).
Install new flashings, valleys, metal edge and vents.
But I am a part time roofer and I will bow to the superior knowledge of our full time, published, resident roofer Hazlett. I enjoy your articles and think they are well written.
Do you really do all your business in a 12 block area?
Rich
Rich,
no problem Heck, by August I expect to be pretty much semi retired from roofing. I will still do it--to take care of old customers and such---but generally I will be concentrating on other things.End of august- i will be 46.- i can still walk, climb, move Ok------my kids are mostly grown and provided for, happy with my house, wife has a decent job, i have retirement money socked away basically- i made mine--and it's time to get out while I still can walk as far as the 12 block radius-- yes pretty much that has been my market.- If I leave that radius-it is almost certainley on a referall from someone within that radiusfor example-- i will finish a roof tommorrow that comes as a referall from a customer 3 blocks away that we did their roof 2 summers ago, tuesday we will start a roof directly across the street from me, and so on----roof after that is a referall from someone 5 blocks away that we did also 2 years ago, roof after that is a referall from someone 5 blocks away that I did last summer, roof after that is a referall from someone i went to highschool with and casually knew 30 years ago, roof after that is for someone else that I went to school with 30 years ago--plus my wife taught her son in school, and i coached him in baseball---and so on, and so on.but-- come august-- i will largely be done with roofing and i will be specifically and systematically targeting a neighborhood about 10-12 minutes away for exterior carpentry restoration(which is what i started out doing back in'87-'88( I got away from it because roofing paid better, and I had 4 people to support)over the years i have mostly portrayed myself here as just a dumb roofer---but I actually have some other skills as well-----it suited me to present myself as a dumb roofer---because that's where the money is!!!Very best wishes,
stephen
I was about to suggest to Steven that we turn this into a thread on how to do roof-overs right.When I first did most of my shingle work it was in Florida and it was always important there to tear off the old. Partly because the roof structure was built with no intention of withstanding snow loads or added weight of any other kind, but more because in that wet hot climate, there was roted sheathing and even framing or fascia to repair nine times out of eight, but you were never sure what it would involve until you opened it up to see.When I moved to Texas, I found myself in a hot DRY climate where high winds and hail were your adversary. Probably 40% of the asphalt or FG composite shingles were installed as layovers. In West Texas, the average life of a roof was 7-8 years because of hailstorms, and most layovers were on roofs that were not leaking and not aged, only showing modest damage from hail that would have shortened its lifespan.The metjhod there was to cut back shingles around the boots and hoods to expose the flashing and use plastic roof cement with 4-6" membrane to seal that junction. Shingles would tuck under the base at each so water would kick out just like always. 'Course, the metal in those boots and hoods was better than we see nowdays. What there is now would need to be replaced totally.
Same method at sidewall flashings. No step flashing there. L-type 4x4 was sealed to the base with the membrane.In Colorado it was all mixed, due to differing elevations and waves of immigration coming thru with tradesmen bringing pet methods from their varyiong climates. Roofs were steeper there, but ice damning was a pretty big concern. The roofs I have stripped that had the most layers were all in the mountains in CO. and none had the terrible problems shown in thOP pictures here. One was a cabin from early settlement days around 1890 and it had every layer of roof still on that it ever had. All five of them.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Anybody seen more than 5 layovers?
The house next door to me is a rental property. It used to be owned by some guy from out in the suburbs, who spent as little money as possible on upkeep. A few years back, the tenants finally complained enough about the leaky roof so he had someone come out to look at it. I happened to be out in the yard that day when the estimator from the roofing company stopped by. He came down off his ladder, shaking his head...he told me there were SEVEN layers of shingles on that roof.
The owner finally sold the property to someone else, who thankfully has been doing a lot better job of maintaining the place.
Anybody seen more than 5 layovers?
Yeah. I got one with 6 layers of asphalt on top of one layer of cedar. I wondered why it had a 1x6 shingle mold. It was hiding the thickness at the rakes. http://grantlogan.net
Who got Bo Diddley's money?
What did they use for nails, 40d?
What did they use for nails, 40d?
Nah. The top 3 or 4 layers were just nailed into the courses below. The cedar shingles were laid on split sheathing, so there was only about a 50/50 chance of hitting solid wood if the nails had been long enough. Fortunately, we tarped the attic before we started because we didn't get a piece of cedar off the roof that you couldn't swallow. It was basically dust.
The amazing thing (besides the fact that somebody actually installed that many layers) was that the rafters were true pine 2x4's (about 11' long - 12/12) on 24" to 30" centers. And the ridges were straight as an arrow. No squatting.http://grantlogan.net
Who got Bo Diddley's money?
Shows you how good that first growth lumber was!
I re-roofed on that had tree poles for rafters here. They were anywhere from 3" diameter to 5", and placed at about 36" OC more or less. I don't think the span was more than 20-22 feet though for th e whole building.I was amazed how sound the place was.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thats what I have on one side of the house,and split ash about 4x4 on the other half ( saddlebag log house). Those Cedar poles then had split sticks for the wood shingles, which I imagine were oak at that time, (judging, by the bits still stuck in nooks and crannies) then in 1905 ( as told by one of the old timers around here) the Terne was installed.
Those cedar poles are still doin just dandy, the 10/12 pitch helps, the half lap joints at the ridge are pegged and it is without collar ties OR joists to prevent spread, the poles just just sit on the top plate log, with big honking cut nails..if the dovetails on the plate log fail...I WILL have a roof getting flat real quick.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"We strive for conversion,we get lost in conversation, and wallow in consternation. "Me.
Five was my max
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
that was my max also. I couldn't believe it, I had estimated 3 layers, man lost on that one!
i don't think i have ever personally encountered shingles more than 3 layers.
most of my customers houses were built in the 1920's--which works out about right for 3 layers at 25-30 years per layer usually the 3rd layer is a squires roof( interlocking shingles--butt ugly)flat roofs-- i am sure I have been up to 5-6-7 layers-----a lot of these houses have about a 1 square flat roof kitchen bump out.
usually the forst layer was some combo of felt and coating--and then over the years layer after layer of half lap and 90#had one customer with a roof---had the first layer of felt---and then the guy had recoated it every year ever since--- I don't think he was the original owner---but I bet he had been recoating it every year for 40-50 years.thing was like 2 inches thick--hard as a piece of coal.--came off prettty easy thouch--once I got under one edge and pryed up-it would shatter into pizza sized chunks----reminded me of that candy we had as kids-Turkish Taffy that you had to slam against something to break it into a bite sized piece???
stephen
Steve, my house was built in the 1880's, last year we replaced, we han 1 layer of shakes 2 layews of shingles. What a mess!
If you are going to bring in flat roofs, I have torn off a pitch roof in Texas heat that was 3" thick. Like to have killed me!
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When we got our house, it had six layers of asphalt over the original 1917 shingles on that part. It was a shallow slope, and evidently always leaked.
We took it all off, repaired it and decked it in 3/4 BCX on a shallower slope, and usewd Seal-O-Flex. No problems for sixteen years.
Forrest
""I encounter plenty of older roofs that had asphalt shingles layed over a layer of slate--and the asphalt shingles lasted 25 years plus"" How did the roofers drive the nails for the asphalt shingles through the slate? That one has me wondering, not doubting , just wondering..
They can't get your Goat if you don't tell them where it is hidden.
dovetail
I was wondering about that one too.
Fake slate?
Rich
I doubt it. Hazlett lives and works in an area I am familiar with , I grew up not far from there and there were a lot of older houses with real slate roofs. Matter of fact when I was a kid our house had a slate roof that was severely damaged by a tornado, I remember the damage, remember the fact it was slate but do not remember how it was repaired.
I have pics of the place with asphalts shingles on it from a few years years after the storm. Hazlett's comment got me wondering if it had been a layover job as opposed to a strip and new shingle. I simply do not remember what was done.
I may have to ask some older siblings if they recall what was done.
They can't get your Goat if you don't tell them where it is hidden.
dovetail,
you can drive a standard roofing nail right through an older roofing slate with no problem( in fact in repair work-that's how you can punch a new hole in a slate for nailing---tap a nail through from the back--which results in a perfect counter sunk nail hole on the FRONT !)in fact here--most of the shingles over slate situations we find--the shingles were nailed over low quality pensylvania grey slate---which is disturbingly easy to drive a nail through.( they are only about 3/16" thick)
i have found many of these older PA slates---that you could easily poke your finger through--they are that soft when weatheredNow--Walter up in main--get's to use slate from Vermont----different animal--twice the lifespan probably of a soft PA slate which might have a 40-60 year life.
Stephen
Thank, I have never worked around slate roofs. Rare animal out here in what was rural Oregon.
They can't get your Goat if you don't tell them where it is hidden.