Roof Over Or Tear Off?

 
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Old 11-19-2007, 10:43 AM   #1
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Roof Over Or Tear Off?


I have a family member with a house in the 15-20 year range in a high wind area. As a result the roof has quite a few folded up/ broken shingles that are now missing.

My question is besides less mess and cleanup is there more of an advantage with roofing over the existing shingles or tearing them off and starting fresh?
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Old 11-19-2007, 10:57 AM   #2
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Re: Roof Over Or Tear Off?


Tear off always. Thank you.

If you roof over you are just putting lip stick on an ugly woman. She is still ugly under neath.

If you roof over, it's like working an 8 hour day, going to the gym, coming home and changing clothes then going to dinner. You still stink under neath.

Always tear off the roof for best quality. If you don't tear off the roof you can not address most of the issues the roof might be having. Have there been any leaks? If so you can not determine where those leaks have been coming from and traveling so you don't know what sections of the roof need special attention. You do not know if there are any areas of rotten or damaged wood and if so you risk wind blow offs if the nails are in rotten wood. If the shingles are curly, wavy, or have any imperfections those imperfections will definetly transfer into the new layer.

There is no advantage other than budget when you lay over.

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Old 11-19-2007, 12:11 PM   #3
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Re: Roof Over Or Tear Off?


Thanks..I wasnt sure if roofing over would leave an extra layer of protection in case of future blowoffs.
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Old 11-19-2007, 12:18 PM   #4
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Re: Roof Over Or Tear Off?


Due to the uneveness of the surface you would be applying the new shingles to, the new overlay will be more prone to wind damage because wind can catch the edges easier.

Also, the additional layer will trap heat sumps between the two layers, which will further deteriorate the bottom layer, allowng the fasteners to become looser more rapidly. The longer the nail used, the more of a toggle affect occurs during expansion and contraction cycles and creates nail back out.

Furthermore, the new roofs life will be decreased by approximately 25 % with a layover versus starting out fresh.

Also, you can not repair any moderately damaged wood, nor install the proper Grace Ice and Water Shirld protection needed if the home is in a wintery climate.

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Old 11-23-2007, 01:51 PM   #5
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Re: Roof Over Or Tear Off?


There's nothing like a new roof - but re-roofing has always been part of roofing industry. Kind of like painting - it would be great if every customer paid me to chemically restrip their homes and plane down their wood and start fresh every time. Paint jobs would last 15-20 yrs. But it would be more costly. So we go over the old paint with prep to remove loose paint. Same in roofing - with less money - a re-roof will extend the life of your roof for a cheaper price. I've seen guys go over the bottom 3 feet of shingles with the granulated overlay - in case the old roof didn't have membrane. And sometimes - it's nice not to have to pitch an old roof and cleanup the mess.
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Old 11-23-2007, 02:15 PM   #6
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Re: Roof Over Or Tear Off?


Tear off only. To do a 'smooth' reroof, you'd need to nail high enough out of the nail groove to void the warranty. Nail in the nail groove, and you will crack the fiberglass mat. Which will also void the warranty.

Of couse to save money, I've known some people to re-roof every 5 years or so. Not sure that they really save anything.
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Old 11-27-2007, 06:03 PM   #7
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Re: Roof Over Or Tear Off?


Some interesting comments on this thread. Like many other things in roofing, the quality of work is a factor of the expertise of the applicator. Re-roofing can be as good or better than a tear-off, at substantially less cost.

Naturally, it takes a slightly different skill set, and slightly different processes to do a quality installation. When that bit of care is taken, the original roof becomes a glorified base sheet for the new roof, and little more. Unless weight is a factor, there is no reason to strip off a first, or even second layer, other than a makework to keep the labor crews busy.

I have (very successfully and in full code compliance) re-roofed over asphalt and wood shingles for years, and every job was (almost) a work of art. I admit to taking a bit longer than normal, taking a bit more care than normal, and taking a bit more cash home at the end of the project.

No one has ever complained that my roofs "looked lumpy" or "looked wavy" or had a funny hump a foot up from the eaves. After a number of years of gauging the new shingles, I adopted the technique I first saw in the Mid-West; butting the top of the new shingles to the bottom of the previous courses. All providing that the last roof was installed by a roofer, not a cowboy with a nail gun or a landscaper with a claw hammer.
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Old 11-27-2007, 06:32 PM   #8
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Re: Roof Over Or Tear Off?


I adopted the technique I first saw in the Mid-West; butting the top of the new shingles to the bottom of the previous courses

We always did our reroofs like that,but because of the need for ice &water shields,it makes a lot more sense to strip and make sure the eaves are protected.
Putting the ice &water over the top of the first course doesn't make much sense to me.Some of the brands will rip too easily to do any good.
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Old 11-27-2007, 08:28 PM   #9
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Re: Roof Over Or Tear Off?


We almost always do roof overs. We do mostly metal products, but if the house is only 12-15 years old and in high wind why would the homeowner go back with the same product that failed. Now I understand there are many factors that can contribute to shingle failure, yet I fail to see the logic in going back with the same thing that failed. If cost is the only thing driving the project than a shingle re-roof will be cheapest. However if they want something that will last metal shingles, tile, steel shake, standing seam or even 5 ribbed metal. All are generally applied with a titanium underlayment or possibly ELK Quantum 30 or equal high quality underlayment.
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Old 11-27-2007, 09:05 PM   #10
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Re: Roof Over Or Tear Off?


Please tear off. I'm in the middle now of tearing off my grandfathers **** thats been overlaid 3 times. Now I have to deal with it. It places another 250#/sq unnecessarily on the roof structure also.
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Old 11-27-2007, 09:31 PM   #11
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Re: Roof Over Or Tear Off?


Plus like Ed said it takes around 25% of the new roof life off
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Old 11-27-2007, 10:03 PM   #12
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Re: Roof Over Or Tear Off?


Thanks for the advice. Definitely plan on tearing off. Also the metal is a good idea. Ive done quite a few roofs on pole buildings using metal, it may be a good application here too because of the wind.
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Old 11-28-2007, 06:44 AM   #13
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Re: Roof Over Or Tear Off?


instead of ice & water shield, put the granulated overlay on the bottom course - that works great for reroofs.
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Old 12-01-2007, 08:38 PM   #14
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Re: Roof Over Or Tear Off?


RE ROOFS should be against all codes in all counties of every state.

cheap people who aren't going to stay in their house long, will reroof to save a buck and screw the next guy who will pay double someday to have it ripped off. i hate seeing reroofs, my roofer will not do them. he'd rather lose the job to someone else than deal with re roofing. it's double the weight on the roof. and some old houses are 2x6 rafters 2' on center. why put the extra weight on it

i can't think of any good reason to reroof other than being LAZY and CHEAP
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Old 12-02-2007, 12:20 AM   #15
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Re: Roof Over Or Tear Off?


I don`t roof over ,but NEI makes a special heavy ice and water shield for that application,where you cut the shingle overhang flush,install metl fashing and the sealant is at that area on the nei material so it sals to the metal edging
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Old 12-03-2007, 05:20 PM   #16
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Re: Roof Over Or Tear Off?


Thanks again for all the input. One more question, will architectual shingles withstand the wind any better than 3 tabs? My thinking is that they will but just wanna get some professional opinions.
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Old 12-03-2007, 05:51 PM   #17
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Re: Roof Over Or Tear Off?


definatly tear off...more work now but less work later. make the roof last
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Old 12-03-2007, 07:35 PM   #18
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Re: Roof Over Or Tear Off?


architectural will hold up better in the wind, three tabs are thinner and will blow off easier, but still takes a lot to do that.
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Old 12-03-2007, 09:58 PM   #19
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Re: Roof Over Or Tear Off?


Agree with most of what tekwrytr said.

In 25+ years; We've never had a problem due to re-covering. However, that was with an existing "3-tab" roof. With today's dimensionals, coupled with the most likely inferior original application...your better off tearing off.

BTW; "Butting" the new shingles was standard practice back when 3-tabs were popular.....wouldn't dream of just going over the existing shingles any other way.
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Old 12-04-2007, 01:09 PM   #20
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Re: Roof Over Or Tear Off?


Do one roof over every three years. The last one I did was only done in a way to help cover the cost of the phone book advertisement.

The funny thing was the job bid tearing off so low figured to the home owner it was a no brainer. Her reply was, "My neighbor did a roof over with laminates and it looks ok". Told her with 5 5/8in lamianates the original three tabs would telegraph through but she didn't care. When I was done it was the only roof I did that year I didn't take a picture of. Sort of walked away from it with my head hung low.

We did all the right things, cut off the over hang, installed drip edge, removed the ridge, replaced all vents, and no valleys to deal with. It was actually easy, three guys 25sq's five hours. Instead of a dumpster we filled up a few totes, it was a three sided house, little waste.

If done again would try to secure 5in laminates but haven't seen those in several years. They've sold the house since and my warranty is gone. The New Horizons would look ok did that on one tear off but now I know there junk shingles.

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