[JoeT]

My goal for a new roof is to put as light a load as I can on the roof while using the good looking architectural shingles. I have three layers on the roof now and have problems in the house which could be caused by having such a heavy roof. I had a structural engineer evaluate the situation and recommended a new roof and I totally agree. The previous owner of the home put the third layer on.

I'm seeing how heavy some of the architectural shingles can be. For example 'GAF-Elk Timberline Prestique Lifetime' weigh in at 337 lbs per square and 'Tamko Heritage Vintage' are 390 lbs per square. There are lighter architectural shingles but are they as considered as good a bet in terms of durability as the heavier ones? Two of these lighter laminated/architectural shingles are IKO Cambridge 30 AR and Atlas Pinnacle which weigh in at 236 and 223 lbs per square respectively.

If we go 20 or so years into the future when whatever shingles I have installed wear out then would it ever be acceptable to put another layer on top of an existing layer of worn out architectural shingles? As a percentage of total cost how much more expensive is a roof job when it's a tear down vs. putting on a second layer?

Thank you for your comments.

 

[Ed the Roofer]

Toss out those Iko and Atlas versions. Geez, those are lighter that a 25 year 3-tab from Tamko or the XT-30 year 3 tab from Certainteed.

Warranty length is becoming a joke.

Too much asphalt weight can also conjure up it's own set of problems, from non-reinforcement and structural cracking called spider-webbing.

Many roofers like the Certainteed LandMark Architectural Shingles or Tamko Heritage Architectural shingles and some are devout followers of other brands, such as GAF/Elk Timberlines.

Value the quality of the installation, "As A Complete System", rather than the material. The Roof installers and the Proper Balanced Ventilation will result in a better pay-off than the decision of which shingle to use, with the exception of those that are deemed to be an inferior "Builder Grade" low quality version.

Ed

 

[Slyfox]

A layover done properly "most of which that I have seen were not" will save you in the area of 10 to 20% of what a re-roof 'tear off' would cost.
One done poorly could save you as much as double that percent, but than you would not get the expected life span out of the shingle tho.

The heavier shingles '50s' you spoke of will last you 30 - 40 years before you start experiencing problems, than you can do some basic maintenance and repairs and get another 5 to 10 years out of the shingle, maybe more.

The lighter shingles '30s' will last you 15 to 20 years and will need some maintenance and repairs to give you another 5 to 10 years.

If you establish a yearly maintenance routine of keeping your roof and gutters clean and inspecting for damage done by winds and ice that are not always seen from the ground both roofs will last there expected life span and than some, of course, assuming they are installed properly.

 

[jaros bros.]

The best option is ALWAYS to remove the old shingles and not to lay over the top with new ones. Ask any shingle manufacturer or good roofing company and they will tell you this. Shingles wear out quicker and issues can arise from curling and telegraphing. Unfortunately, homeowners trying to save money and contractors trying to win bids have propagated the belief that nesting is a good idea. It has never been "best practice," only "acceptable practice."

 

[Dale Chomechko]

Roof trusses are made to carry 7.5lb per sq ft (750lb per 100 sq ft)
Weight is not an issue if you tear off the previous roof or even add a layer.
Sly fox is right, the 20% you save will probably be lost on the life of the roof. besides forming to the shingles underneath and not looking the greatest.
Dale Chomechko
DC Roofing Inc

 

[Slyfox]

The best option is ALWAYS to remove the old shingles and not to lay over the top with new ones. Ask any shingle manufacturer or good roofing company and they will tell you this. Shingles wear out quicker and issues can arise from curling and telegraphing. Unfortunately, homeowners trying to save money and contractors trying to win bids have propagated the belief that nesting is a good idea. It has never been "best practice," only "acceptable practice."

Manufacturers not only except layovers but they actually provide a spec sheet for the installment process.
Layovers only leak, blow off or prematurely fail when there not installed properly.
I absolutely always reccommend a re-roof rather than a layover,
but I don't lie to people by telling them a layover won't last just so I can scare them into doing a re-roof.

 

[JoeT]

Thank very much for your responses. I'd never be able to get this kind of information otherwise.

The roofer that I'm thinking of using gave me an extra cost option to use Timberline Prestique 30 year shingles. He gave me a copy of the GAF/ELK Timberline catalog and I can see there is also a 40 and 50 year Timberline shingle. I'm going to ask if he can get the 40 year instead of the 30 year. For my situation that seems to make the most sense.

This is off topic but I'll ask anyway. I have a choice between using two different roofers. One uses a large crew and does the entire job in one day. The other has as smaller crew and does the job over two days.

I'm wondering if the two day job might result in a higher quality of workmanship than one day 'rush' job. My assumption, which could be completely wrong, is the one day job is under too much pressure to just get the job done. The two day job takes some of that pressure off the workers so they can concentrate more on doing the job right.

Of course it might be unfair to ask this question because the answer is "it all depends". If you have a crew of 12 and they do it one day and a crew of 6 doing it in two days then each member of the these two crews is still going to be just as busy no matter how large the crew is.

The two day job does cost more than the one day job. The one day job come with a 20 year labor warranty.

 

[jaros bros.]

Slyfox, I was differentiating between what is accepted and what is best practice. If you will carefully read the warranty information, if the old shingles curl in anyway underneath the new ones and cause problems, there is no warranty. This does happen often. I have seen it and replaced roofs because of this. It might look good for the first 20 years, but you are adding to the probability of failure. You know that and that is why you "recommend" reroofs from scratch. The chance of a nesting or bridging job failing is higher because you have added components that now must not fail. The more parts you have, the greater the chance to fail. For example, I had a job by a gc that wanted me to nest over a roof that was already leaking. On the porch most of the shingles has a slight curl. Now, the gc said that he had already gotten the job to nest and I could see that there were going to be serious issues with this. I did not take the job because I knew it was wrong to do it this way. Now, if there were no leaks, and the shingles looked great, yes, I would have nested on top, but not with this roof, and not with most because it is not best practice and not many roofs are acceptable for nesting. Again, notice I am merely differentiating between best practice and acceptable practice. I am not saying nesting is wrong. Unfortunately, a lot of contractors are willing to do whatever they can to get the job, including not ripping of roofs because they know they can get work if they can do the job cheaper. And the customer, none the wiser, thinks this is a great idea. Of course this is not necessarily directed at you just like I know your last comment about lying was not necessarily directed at me.

 

[jaros bros.]

Joe T, the size of the crew doesn't really matter. You need to choose the one that you feel most comfortable with. I think that your analysis of the getting a better job with the two day crew is sometimes true though, but not necessarily. Take all the information you've gathered such as references, appearance, and how they came across to you and decide on those things and you should do alright.

 

[Slyfox]

Your right, when I spoke of 'lying' I was talking about a manufacturer rep telling you they don't warrant layovers, I just went through the list of contacting them via the phone a while back to make a point about layovers in another post and reps from GAF/Elk, Tamko, Certainteed, OC, IKO and Atlas all had specs for me.

The warranty issue is the exact same if you don't have proper ventilation,
over growth of tree's, etc.

I to have seen far more layovers fail than not because like you said,
there's a lot of roofers out there who simply want the fast buck and skip steps in the installment process.

I have only done something like a half dozen layovers since I started Fox Roofing in 1994, but all of them are still in good shape and problem free.

 

[Slyfox]

Joe T, the size of the crew doesn't really matter. You need to choose the one that you feel most comfortable with. I think that your analysis of the getting a better job with the two day crew is sometimes true though, but not necessarily. Take all the information you've gathered such as references, appearance, and how they came across to you and decide on those things and you should do alright.

He's right Joe,
a large crew may be faster, but that don't mean their providing the same or better quality.