Layover

1967 chevell

I generally do not do layovers, in fact haven't done any, all tear offs. Is there anything I need to be aware of when laying over top of existing shingles. I will try to talk them into a tearoff though.
I would assume that I still need to stick down the shingle starter and peel off the existing cap but what else?? Would you price it as a new construction shingle job?

2ndGen

Easy. As long as the 1st layer is in good shape.
You'd be lucky if they are nice and straight so you can "butt" them up.
Massive time saver.

Drip Edging, Vent Boots, Seal the chimney if it's in solid shape (or go crazy and re-flash it).
I&W in the valleys and eaves if only for nail sealing.

Remove any lumpy tabs/fill in any missing tabs.

Important: Walk that roof and check for rotted wood (from inside would be even better).

Pricing it? Get a hundred/sq labor.
It's way quicker money than tear-offs!
(depending on pricing structure locally)

A lot less that can go wrong as far as accidents go, damaging the property, super easy clean up.

If this is your first, you're going to be shocked at how fast you get in and out when compared to tear-offs (no massive set-up/prep/protection time!). You're trash and waste should fit in a pair of contractor bags for every 10 sqs.

Let us know how it comes out!

__________________
"I've been up on the roof. I know what those guys go through.
My whole life has been about making that profession respectable."
Ken Hendricks
www.SolutionsRoofing.com

MJW

I would check to make sure it is legal first. Check out the IRC code in your area. Here, we cannot do any overlays.

Slyfox

1) Remove small sections of existing roof system for proper inspection of roof deck.
'if you find soft/saggy sections while walking the roof'
2) Remove tabs of existing shingles (3 courses up from eave).
3) Cut exsisting shingles overhang on gables back flush and install new dripedge.
4) Remove all existing hip & ridge caps.
5) Remove tabs of existing shingles from all valleys.
6) Visual inspection of all existing wall and chimney flashings (both sub and counter flashings).
7) Install new roof system.
8) Clean-up of all debree from old and new materials and haul them away.

I always reccomend re-roofing as well, I have done a few dozen lay-overs tho and they work if installed properly.
One good point to help change there minds to tearoff/re-roof is to mention how most insurance companies and material manufacturers strongly reccomend against going that route.

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indm45

2nd gen, correct me if i,m wrong,but wouldn,t 90lb be ok for the valley,s.isn,t ice and water suppose to adhere to straight decking.

2ndGen

Well, today's 90lb isn't no where near as good as it was 20+ years ago.
I'd use SBS instead of 90lb if one didn't want to use I&W.

And yes, you are correct...I&W is for use on decking.

It's not warrantied for use directly over shingles,
but it does stick to shingles and nails that penetrate it are still sealed.
90lb and SBS with nails through it don't seal around the nail.
And it installs far easier than either.

__________________
"I've been up on the roof. I know what those guys go through.
My whole life has been about making that profession respectable."
Ken Hendricks
www.SolutionsRoofing.com

RooferJim

Its rare that we do them only a couple a year. "usually when they want to sell there house". make sure you use longer fasteners. back in the old days we did them all the time.

DavidC

In my good ole days we did more roof overs than tear offs. It was always done to save $$$. Some of our tears offs were 7-8 layers thick. You could almost hear the house sigh with relief when it came off. Today the maximum allowed is 3 layers, but I've heard there is a move to limit that to 2.

When I started selling my own jobs I had decent luck with explaining that it was actually less expensive in the long run because the new roof will last much longer if you start from a clean deck. Times have changed here too, people have more to spend on renovations and prefer to do it right. Or so it seems anyway.

2ndGen and Slyfox both have laid out acceptable practices in my book. Only thing to add as I see it is keep it to no more than 2 layers total. I've read recently that they consider every layer will reduce shingle life by half.

Good Luck
Dave

__________________
www.CookContractingLLC.com

MJW

Shingle manufacturers won't warranty much with a second layer, if anything. They also say to NOT use any underlayment on a second layer.

Roofsafe

The new code for layovers is two max, if you are going over the old with three tabs you can butt and run, if you are going to use laminates you need to inform the HO about bridging, as metric over standard will bridge.
If the old shingle is metric then you can butt and run the laminates. Run into both out here.

Slyfox

I also read a few places about the 'half life span' isuue with lay overs,
I haven't read anything as of yet that makes me buy into it tho.
The lay over 'second layer' on my personal home is 18 yrs old this month,
OC 25 yr 3-tabs, on a 4/12 pitch.
No leaks, no blow offs, no curling, so it's allready surpassed the half way mark and is still holding up fine.

We also will not do a third layer of roof, never have,
Code won't allow it, but thats do to the weight your putting on the structure, not a life span issue.

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1967 chevell

I am getting ready to do this aforementioned job. One question-Can I just use Style C drip edge around the perimiter??

Roofsafe

I trim the rakes and faces, style 'D' on the rakes, and depending on the gutter, if its high on the face or lower I will use style 'A' 2X4, steeper roofs I will use style'A' 2X4 120 degree. Puts an end to leaking behind the gutter, people like that.