Roofing Layover Question

I am interested in doing a layover on my roof. It is currently a single layer of 30yr laminate shingle. I have heard that you can only put a second layer on 3 tab and not laminate. Is this true?

you are 100 % - Do not go over the top of a dimensional shingle.

Mr. 71 is correct…again.

one of the reasons not to go over a dimensional shingle…is it will look very lumpity dumpity (bumpy)

tear it off!!! and dont wear gloves

Are there any other reasons to not do it. My roofer said that it is not a problem. I am pretty tight for money and I am not only going to be in my house for 4 more years before I sell it. Thanks for the previous advice but I need more sound reasons.

Having a nice new roof that was installed correctly would be a good selling point when it comes time to sell the house.


Buyer-" I would like to buy your house, but the roof looks pretty bad and it will cost me twice as much now to tear off two roofs and replace. I will have to ask you to lower your selling price by $ 20,000 ."

People go over shingles all the time regardless of type, it’s not going to make your roof blow up or cause a chemical reaction of any kind. It is in my opinion very poor practice and it cuts down the life of your new roof considerably. Check local ordinance to see how many layers, etc. are allowable by law in your area. Also take into consideration that many problems such as flashings can only be addressed with tar or caulking in this scenario which is crap.

I don’t to “re-covers” because more often than not they are half assed installations at best and it will come back to bite you later. My advice is to take the difference it would cost you between a full tear off and a re-cover and add it to the cost of the house when you sell it in four years.

Has any research ever been done on the subject of shingle lay-overs causing a decrease in shingle life of the newer roof? Cuz I have torn off some pretty old re-roofs that lasted longer than originally intended.


You can also repair the roof till you have the money to tear it off.

I have held many roofs together till the people had the money. Roof cement, tarps, geo-cel…

much better than what he`s thinking,lefty :wink:

You can trap additional moisture & heat with a 2nd line. If it takes your house (in summer on a 90 degree day) 2 hours past sundown to reach a temperature similar to the ambient air temp, then with a 2nd line you can easily expect an extra 30 minutes or more depending on the color of the top layer. Multiply 30 minutes of A/C runtime over 90 days of summer x 4 years: 180 exra hours of operation on your A/C & using electricity.

IF & only if you do a layover, (which none of us like to do but would do only if someone absolutely had to have it & were paying appropriately & if we could warrant the entire envelope & there weren’t problem areas like chimneys or other areas of concern & the customer signed all kinds of waivers of liability & went on video witnessed by a Supreme Court Justice stating they understand & agree to all of the above & below terms)…

If you do a 2nd lay, make sure they put felt inbetween the layers & the first course that’s visible has the top of the shingle cut back enough to start a correct lay.

If your first layer of shingles is done with wavy gravy lines (have to get on the roof & look down line) then the next layer has to almost completely match this or it will look “lumpity bumptity” as ^ said. :slight_smile:

If you have a house that was built in '75, that’s a 30 year old roof which possibly even has a 3/8" deck (the thinnest allowable in some areas). It won’t survive a 2nd lay without eventually looking “friendly” (when you drive by, the roof will wave atcha). The next roof will also look wavy. & The one after that. The only way to get bad humps out of it is to do a total redeck. On a 25 Square job, I’d be charging a minimum of an extra 3,200.00 - 80 pcs. of 1/2" @ 10.80 each with tax plus $ 20.00 a sheet labor to crew + contractor’s fee.

For the next owner, they might have this expense PLUS the added cost for twice the labor on removal. If it is such a size that a 2nd line removal will put them into a 2nd day’s work to do a total re-roof, then they are going to want 2nd day’s wage. Nobody here on this board likes to run into a 2nd day where they now have domino “late start” roofs going on all week because of one problem child project.

If you have a leak somewhere, it’s much more difficult to get the problem diagnosed when there’s a 2nd lay.

If I was doing a real estate inspection for someone & saw a 2nd line, this kind of breakdown of potential / future issues is exactly what I’d explain.

Using the same 25 Square roof, the maximum it should cost you in labor charges is around $ 750.00… if your credit is in good enough shape but you can’t afford the better quality repair, get a home improvement loan.

IMO, any roofer who suggests a 2nd lay is a crappy roofer (or even worse, a sales-hole who is only looking to make the sale). But that’s MY opinion & I don’t fully know your situation, location, available resources, motivation, abilities or whatever, etc.

One sugestion - see what they’ll charge you for doing the dump portion (if your typical roofing market uses dump trailers vs. onsite rolloff dumpsters). This means you get all your buddies together to do the tearoff by yourselves; with 5 guys on a 25 square 6:12 house with no experience, it should take one full day.

Anyone else have any other sugestions?

PS: Did I mention “don’t do it” yet?

You can not go over dimensional shingles there voids all warrantys. Do a repair if you can or replace the roof.

yeah - i agree !!

ill get in there with ya Aaronb.
i too have also torm off many ten plus year old 2nd layer roofs.
so it does work. done it before my self many times.
not going to be as good of a job as tearin it off no,
but it will look better than what you have now.
make shure ya use 2"+ roofin nails.
nail em by hand.

good luck.

Seriously gweedo are you off your meds? How can you give that advise knowing it will void the warranty?

I will say it again going over a laminated shingle will produce 2 things a very bumpy roof and a voided warranty.

Aaron im not sure if there had beena study persay. But i have had some old customers homes we did 10 + or so years ago look not so good. Only reason why i know i did them is because they are across from the ex wifes mothers house. Went over 3tabs and the roofs look bad now curling up.

Maybe we should call mythbusters and find out. Hold on im off to M5


I am going to lay some and see what happens. I can not picture it looking that bad.

I have seen layovers last 20 years. The ones that do not last were probably cheap shingles to begin with.

In 26 years if I did 15 layovers I am lucky.


I am going to lay some and see what happens. I can not picture it looking that bad.

I have seen layovers last 20 years. The ones that do not last were probably cheap shingles to begin with.

In 26 years if I did 15 layovers I am lucky.[/quote]

we are not saying you can not do a layover…we are saying you def. should not do a layover on [size=150]dimensional[/size]

Hi Marshall exteriors,

I heard exactly what you’s are saying.

I do not march in line behind everything that is written. So I want to see for myself how bad this will look.

As for the manufactures warranty? How much is that really worth?

I sell GAF shingles because I belive the shingles are of good quality. Not because I think the warranty is of good quality. I use 150 Smart Choice warrantys. 15 Golden Pledge Warrantys. Plus I personaly warranty 300 gutter installations with a 20 year workmanship warranty a year. I issue 100 edpm and pvc warranty a year. Some with the manufacture, the others are personally. If the manufacturer does not stand behind there warranty I will. So I have to believe the installation and the shingle will last.

So if I believe the timberline’s can be installed over timberlines. Then I will install them over timberlines. If the case arises that it is cost effective for a particular building.

I am here to learn. Not shut down descussions on new or different ideas. I have been thinking about this for a couple of years. I am going to do the reseach because of this thread.

but its not a new idea… i have seen it hundreds of times…all with the same results. lumpy and ugly. as far as a 20 year wrkmanship warranty. what happens if i get in a car accident tomorrow? i will be gone…but the manufacture will still be here. thats why i believe in a manufactutre warranty over a personal warranty. im not saying your wrong on any account, people should stand behind what they do…just how i sell.