Re-roofing - layers

[Bruce Page]

It’s time for a new roof on the old abode. What are the disadvantages of re-shingling on top of old shingles? I’m told I can save ~$1200 if I don’t have the roofers strip the old roof off. My inclination is to strip and start new but is it that important?

[Jim Matthews]

You won't know the condition of the roof and underlayment, unless you strip off.

If the contractor has a track record you can verify, and a can be held liable for any future leaks,
overlaying the old shingles means less in the landfill, and lower expense (removing the old roof takes heavy labor).

Check with your building inspector about how many layers are legal for your structure, and how many are currently applied.
https://pro.homeadvisor.com/article....les.13861.html

Here in "Hurricane alley" overlay roofs are the first to shed shingles when the wind howls.

FYI - If you do need to strip off, consider a metal roof or elastomer covering.
The lighter colored membranes and metal roofs reflect a great deal of the sunlight
that otherwise heats the building interior.

[Bruce Volden]

You won't know the condition of the roof and underlayment, unless you strip off.

If the contractor has a track record you can verify, and a can be held liable for any future leaks,
overlaying the old shingles means less in the landfill, and lower expense (removing the old roof takes heavy labor).

Check with your building inspector about how many layers are legal for your structure, and how many are currently applied.
https://pro.homeadvisor.com/article....les.13861.html

Here in "Hurricane alley" overlay roofs are the first to shed shingles when the wind howls.

FYI - If you do need to strip off, consider a metal roof or elastomer covering.
The lighter colored membranes and metal roofs reflect a great deal of the sunlight
that otherwise heats the building interior.

I 2nd the metal roof. Be done with it.

Bruce

[Bruce Page]

Jim, thanks for the link. There’s just one layer on it now and I was told a second layer is both legal & common. We do get some big canyon springtime winds here, I saw 90mph once. Your point on not knowing what is under the shingles is a good one..
I have a guy coming next week to give me a quote on a metal roof but I think the cost is going to be more than I want to spend.

[Jessica Pierce-LaRose]

I was surprised to find our roof had two layers, given that we thought it was a hundred years old. Turns out there's cedar shake under the slate!

[Frederick Skelly]

If I can afford it at the time, I prefer to strip the old roof and start fresh. As noted, you can verify the underlayment. You also reduce the weight on the roof.

But youre absolutely right - its common and legal, though it always "feels" like cutting a corner. But Ive done it both ways, depending on cash flow and how long I planned to keep the house.

Metal roofs are always tempting, but they cost more.

Good luck!
Fred

[Pat Barry]

2 layers very common. Lets assume they are laying flat, well adhered a 2nd layer is perfectly acceptable. Lets assume they are curling up, etc. then start fresh. Lets assume you get the low bidder to do your work - they will strip it and be putting on new before you get home for your lunch break. Lets say you want to inspect it then - you better be there when its time or you may not get the re-roof completed in the one day planned. Bottom line - you have to trust your crew to do the right thing.

[Michael Mahan]

when I did mine there were 4 layers & the 2 bottom layers were mostly just dust & small gravel . the tar paper was all but gone too.
here local code is 2 layer only allowed how they got away with the other 2 I'll never know , but when they got the layers off the roof there were slats underlayment & they were too wide of a gap for code as well , so I laid down 1/2" OSB , added a ridge line vent , installed a photo solar array
because of the 4 layers the roof "Had" a slight sag now that is gone
40 year single on it now went with a light sand color to reflect the heat off & now the house is much cooler in the summer (that ridge vent really helps cool )

[Steve Rozmiarek]

Only 1200 to strip it? That's pretty cheap, and then you won't be worrying about it later. Adding to what Pat said, you have to trust the crew though, some fly by night outfits do some pretty ridiculous stuff.

[Mel Fulks]

Metal is great but a LOT more money. Got bids few years back from 16,OOO to 25,OOO for different types made of metal.
Bought a thick top rated asphalt for thousands under low bid. If you use the thick asphalt you must tear off old roof as it is much heavier than standard.

[Andrew Fleck]

Your new shingles won't last quite as long if they are nailed over existing ones. It typically takes 5-10 years off of the life of your shingles. I used to be a roofer once upon a time and the premature shingle failures were almost always on roofs that had two layers on them already. It may not matter to you much if you get some good quality 30 year shingles though.

[Matt Meiser]

That question sounds familiar....http://www.sawmillcreek.org/showthre...-off-or-reroof

My parents didn't do a tearoff about 15 years ago and are doing a new roof this summer. If we have summer...

[Lee Schierer]

I vote for removing the old shingles. Getting the new shingles to lay right even on fairly flat old shingles makes for a less than perfect looking roof. With the shingles removed, you can see how the sheathing looks and make quality repairs as needed. I also refuse to have OSB used on my roofs as the heat seems to destroy the glue over time and even a minor leak results in major problems with OSB.

[Ed Aumiller]

How old are you and how long do you intend to stay in that house...

When I was 25 about 7-8 friends all built a house at the same time I did... I put metal on mine.. Standing seam galvanized...
Still have same roof with absolutely no problems.... the others have had to replace shingles at least once and most of them twice...

So in the long run, even though the metal roof cost more initially, it is cheaper in the end... my wife is younger than I am and will probably
live another 30+ years and she will not have to worry about the roof....

[Brian Libby]

Strip the shingles! Your replacement shingles will last longer and have a flat surface to lay on plus you will know the condition of the roof boards