Expert opinions differ - Who is correct?

Hi Guys. Last weekend’s storm on Long Island ripped 1/4 of my shingles off (two huge patches on the dormer) so I’m in the process of getting estimates for a whole new roof - but two contractors are giving me completely different expert opinions. The house is a cape with a half dormer in the back. Single layer of 20+ year old shingles. None of the shingles are curled, but the rear ones have become brittle from the sun and the front roof (mainly in shade) has lots of small clumps of moss growing on it. Problems I have had are (1) an ice dam across the edge of the dormer backing water under the shingles and (2) rain running down the roof hitting a chimney face and leaking in past the flashing. (I put up a metal strip-like diverter which remedied the problem.)

Contractor 1
Says the front roof is actually in better shape than the back despite its discoloring and the moss. Would build a “cricket” at the chimney to divert the water around it. Recommends tearing off the entire single layer because “a second roof will always have a shorter life due to the first roof baking underneath it”. He’d put down ice barriers, architectural style shingles, and vent cap shingles along the peak. He mentioned that roof rippers charge by the ton hauled away - so I make out well in that I only have one layer to rip off.

Contractor 2
Says front shingles are in worse shape than the back. Recommends just brooming off the moss in the front and nailing down a second roof to save a ton of money. But recommends ripping off the dormer roof in order to apply an ice shield there. Says all I need is a metal diverter at the chimney similar to what I have already. He doesn’t recommend the roof peak vent shingles (I do have a mushroom with fan) because of the relatively shallow roof angle of the dormer. Says if a storm blows hard enough from the back it could push rain water back up into the vents and into the attic. Says roof rippers charge by the roof area and not by weight hauled away.

This is more about getting it right than about the money. So can you guys please tell me what aspects of these expert opinions might be correct?

Thanks.

If the rear dormer is the typical Cape Cod style that we see in my area, then you would be needing a low slope roofing system on it, instead of shingles.

Are they saying that they don’t tear off the roofing themselves?

As far as a second layer not lasting as long as the first… I have heard people say this, but have never seen any sort of science or research to confirm or deny it.

Is the chimney in the dormer section?

I don’t know the exact slope of the dormer. Not flat, but pretty easy to walk on. The the first contractor commented it was surprising I had experienced an ice dam because he thought the slope was a little better than he sees on most dormers. The problem at that time was we had a snow, then a partial daytime melt, then a night freeze, and then some heavy rain. Got up on a ladder and broke the dam (just within reach) open with a hammer and was almost knocked off the ladder by the unexpected gush of water. Couldn’t believe how much water was up there.

At this point, it is sounding to me that they may use a subcontractor to rip off the roof - or maybe they were just talking about the cost of carting it away. Not sure.

The chimney comes out of the steeper front roof, not the dormer.

UPDATE: Contractor #2 returned today to take a better look at the roof as promised (he lives in this neighborhood) and he is now of the opinion that the entire roof should be ripped off. After reading discussions in this forum regarding whether to rip or put a second roof, I was going to tell him to rip the whole roof anyway. Seems the economically smart thing to do.

Here are two photos of the house just to show the chimney situation and dormer slope. However, these are dated photos but the best shots have at the moment.

http://i850.photobucket.com/albums/ab62/bcicio/P0000618.jpg
http://i850.photobucket.com/albums/ab62/bcicio/P0000620.jpg

I like #1. A cricket is the right thing for that chimney. And I would be leary of anyone who advocates a roof-over. I have done them to save a HO money but never recommend it. It is always better to tear off.

I’d go with #1, too. And I truly beleive that going over existing shingles usually shortens the life of the new shingle. Its what Ive seen with my own eyes.-Ray

If it were my roof:
I would tear it all off
inspect sheathing for any deterioration
inspect all flashings
Build cricket/saddle
Install ice and water 6 feet up from eaves
Install Ice and water around chimney and all soil stacks.
Use Synthetic underlayment
Re-flash chimney and install reglet.
Use arch shingles (Wind Nailed)
Use shingle vent II vented ridge (Hand Nailed)
Roofer #2 sounds like a hack
Stormer

Have any of your friends, relatives or neighbors used either of these roof contractors? See who your neighbors have used and maybe get a 3rd quote.

Cricket is the way to go, my chimney is like yours (against the wall) and I built a small cricket, worked wonderfully.

Tear off the old roof. It will cost you more, but it is well worth it. No issues of old stuff penetrating your new roof, no ugly humps and heaves. And apparently it is against our local (British Columbia, Canada) building codes to go over an old roof with a new one. Something about the old roof starting a flash fire at 200 degrees…

It would be hard for a tear off crew to estimate a job if they went by weight, that’s why they do it like Cont #2 said and measured the roof area. They have an idea how much a square of roofing weighs, so after they measure, they can give a decent estimate.
Going by weight you won’t know how much to charge until you dump it.

Your rear dormer isn’t that low of a slope, probably a 4/12. Ice and water and shingles.

Not advocating re-shingles here, but I am wondering exactly WHAT deathray saw with his own eyes to make him believe that going over an inert material with another inert material shortens the life of said second inert material.

There is only one option when there’s this much discussion about a roof…start from scratch.

Take it to the deck and do it all brand new.

You can’t go wrong and it will save you money to put in a completely new roofing system.

BTW, I applaud your caring more about quality than cost.

I think you’re gonna be alllllllright!

:wink:

I’m definitely going to go for the total tear-off. Makes sense to check the condition of the underlying wood after 20+ years and to put down ice barrier sheeting. But what about the comment that rain water falling onto the dormer roof could be pushed back by the wind and into the string of peak venting shingles if installed? Is that likely considering the degree of slope you guys see in the photo? Keep in mind this weekend’s nor’easter (more like a hurricane) was blowing in that direction and ripped a ton of shingles off. Might they make peak vent shingles that vent only on the steep slope side for situations like this?

ALL chimneys in the North East should have a cricket behind them.

Ice damning can be fixed by applying Ice and Water Barrier type membrane 3’-6’ along the eaves and directly onto the wood decking. This should have felt paper over it otherwise the shingles will adhere to it in the warmer months making it very difficult to impossible to repair in the future. This should be done in conjunction with good ventilation.

Hope that helps.

Um, you didn’t know that? Seriously?

Option #1 for sure.

[quote=“Tar Monkey”]ALL chimneys in the North East should have a cricket behind them.

Ice damning can be fixed by applying Ice and Water Barrier type membrane 3’-6’ along the eaves and directly onto the wood decking. This should have felt paper over it otherwise the shingles will adhere to it in the warmer months making it very difficult to impossible to repair in the future. This should be done in conjunction with good ventilation.

Hope that helps.

Um, you didn’t know that? Seriously?[/quote]

Oh, I have heard it spewed thousands of times, but never seen any studies or scientific data. That’s what I’m looking for.

Um, you didn’t know that? Seriously?

Oh, I have heard it spewed thousands of times, but never seen any studies or scientific data. That’s what I’m looking for.[/quote]

I don’t know of any truly scientific studies to back up the claim.

The common sense and experience of my brethren is good enough for me.
It is good practice to remove old roofing before applying new roofing.
If you can’t see that, well there is no help for you.

It seems you like to disagree just for the sake of disagreeing.
That is too bad because I have been reading you for a long time now I am quite confident that you are a knowledgeable experienced roofer.

Don’t let that chip on your shoulder weigh you down.

One of the theories as to why a second layer of shingles won’t last as long as a clean install is that with a 2nd layer the roof will retain heat for longer.

It has been scientifically proven that the deterioration of asphalt is primarily due to UV and heat.
Experienced roofers know that when tearing off a multi layer shingle roof the shingles are more brittle and dried out.
Many of us refer to this as “baked” shingles.

Based on what I read here and elsewhere it appears that asphalt shingles don’t last as long in the hotter climates of the south and southwest.
It also appears that the thicker the shingle the faster they will dry out and become brittle.
This is consistent with the theory that asphalt degrades quicker under conditions of prolonged high heat environments.

[quote=“AaronB.”]

Oh, I have heard it spewed thousands of times, but never seen any studies or scientific data. That’s what I’m looking for.[/quote]

If a person sees it first hand and scientific data say’s otherwise, should they then believe the scientific data?

Just getting back to the ridge vents…

I pressed the No. 2 Contractor about the ridge vents today, questioning whether the rain water could really get pushed up through the slots in high wind conditions across the dormered roof as I thought the slant of it was pretty decent for a dormer. He still felt confident that it would happen and offered another reason against installing the ridge vents. He explained that because I have a well-made (Nutone) mushroom vent with exhaust fan, the fan would actually wind up drawing in hot summer air through the ridge vents, basically replacing old hot air with new hot air. Sounds pretty logical to a lay person. Can I have some thoughts on this?

Aron, maybe its because I live where its 95-115 degrees all summer, but they dont last.The house I live in now hasblack Tamko shingles (dimensional) over the top of another dimensional. Roof is 7 years old. Laminates are delaminating and the shingles are brittle and lose granules easy. I didnt do my roof, some illegals or the prior h/o did. If I had time right now, I’d post pics for ya, its a good laugh.-Ray

Don’t do a layover.Start from scratch.It is not that much more money.A good roofer will always tear off unless he has zero work and needs cash.( I’ve been there)

A lay-over will void the manufacturers warranty. I recommend building the cricket . The power vent you have is a great vent system as long as it’s working correctly,but if it were my home I would remove it and cover up the hole and go w the ridge vent(no up-keep).Don’t worry about the water coming in from the sides,that will not be a problem.