2nd layer of shingles or tear-off/re-roof

[ArkTinkerer]

Title pretty much says it all. Roof is getting old but no major issues. Want to add a ridge vent if that matters. Debating just applying another set of shingles as opposed to doing a full tear off. I've seen houses with three layers and don't think I'd go that far but two layers doesn't seem to be a problem. Anyone do a second layer and run into problems? Does the second layer add insulation worth mentioning?

ArkTinkerer

[little jimmy]

I have always taken the old ones off. It is just my prefference. Lots of people do two layers and dont have a problem. Heck one rental had wood and then three layers of asphalt on it. As for insulation, I would say that there cant be much if any value to think about. If the old ones are rolling up then it will be hard to keep the new laying flat. Good luck either way.

[Toolman12]

I have put many shingle roofs down before with my father and IMHO if the existing shingles are not rolled up or missing then go ahead and go over top. if they are rolled then just cut the tabs off it's a lot less waste to have to haul away. Use longer nails and wait for a few of good hot days to put them on so they seal fast and strong. the advantage of complete tear off is seeing if there is any damage to the roof itself a company will always want to do this because it adds to there bottom line. So if no leaks and no rot then save a lot of time, money and mess and just go over top IMHO

[Norcal]

Remove the old ones, overlay roofs are a poor practice. Stripping the roof also makes possible for the sheathing to be repaired if needed.

[Big Poppa]

dont do a second layer of shingles unless that is all you can afford.... always better to strip it down to the boards....

[79firebird]

I my self perfer to tare off and not do a second layer depending on how the roof truss's are due to all that added weight.

[NUTTSGT]

I've often heard that if the current shingles are in decent shape, you can put a second layer on them. It makes me wonder to myself, if the shingles are in that good of shape, why are you putting new ones on?

Just my 2¢, I'd tear off the old.

[bob15]

Strip it. It's a no brainer.

Not sure where you live, but consider the weight of a second coarse of shingles, plus potential snow loads. Sure it might seem petty, but if you're in the North and get a record year of snow, collapses can and will happen. Your house will be happy without the extra weight.

Plus, by stripping it, you can lay down water & ice which will help prevent water damage should you have ice dams on the gutters. Also gives you a good chance to see how your plywood or tongue and groove roof boards are doing.


bob

[signcrafter]

Tear it off, no question here.

You will NEVER get as good of a seal going over the top of another layer. Roofing materials are like a puzzle with the ice dam, tar paper, valleys, flashing, etc. Tear it off so you can see any issues there may be that you can't see right now. Then start fresh. You will have piece of mind that you did the job right. With the wood in good shape start putting the pieces together. The roof will seal better and lay flatter. Think about it this way, when you put new shingles down you put them down on a flat wood roof with flat tar paper/ice dam on it. If you put a second roof on you are putting it on shingles that aren't really flat, they have spaces and also years of deterioration from the weather, even if they look in decent shape.

I've helped a few friends in the past do a second layer but I would never do it on my own home. The little bit of work it takes and cost to haul away it's just not worth it.

Now the one time that I might consider it is if I found cedar shakes under the original layer! I've done a few roofs that had two layers of shingles and cedar shakes and those suck. Take forever to tear off and then have to re sheet the roof. Not fun and in that instance I might consider just putting a second layer on!

[jeep450]

As long as you have regular 3 tab shingles. If you have architectural shingles you have to tear off because the weight will be too much.

[Falcon67]

Well - if you have, say you have 20 square up there of regular 3 tab. That's about right for a 1600~1700 box sq/ft with a 6/12 pitch. You'd double the weight from around 4500 lbs of shingles to 9000 lbs of shingles. Then next time, you HAVE to take them off. Think about the amount of extra work, the size of the dumpster to get rid of them, etc.

[nkachur]

This is an issue you will never have an agreement on. In my opinion strip the roof, it will allow:
- you to repair any sheathing damage
- reduce the weight load on the truss / rafter system
- get a better lay

the only advantages to putting a second layer on are:
- less work
- no disposal fees

If you can afford to upgrade metal is a better product than asphalt for your replacement.

Just my 2 cents.

[Gary S]

I've done it both ways. The second layer adds weight, but if your roof is structurally sound, it isn't an issue. I live where we get very heavy loads of snow some winters, and have never seen a residential wood frame house fail to handle the snow load with two layers of shingles. I see failures on commercial buildings designed by architects and engineers, but not on wood frame houses.

So, it is your choice.

[joshmodelskidoo]

if theres no damage and the shingles are still ok, the drip edge is good and no leaks i would just slap on another layer. i have herd of people even doing a 3rd layer buy i wouldn do that. depending on how steep your roof is you might want to put on some ice berior also. i have to redo my roof with a single layer on a double wide with rotted wood under the shingles on the overhang so its all getting torn off and iinsulation while im at it. you can always call up some roofers and see what there opinion would be

[Stuart in MN]

I think most building codes will allow two layers of shingles, and if the first layer and roof deck are still in good shape you can probably get away with it, but I think you'll be better off stripping the old shingles - that way you can be sure there are no hidden problems.

[Boomer343]

Check the warranty on your new shingles....most require certain underlays and if installed over existing shingles the warranty may be void.

Personally I'd strip and cover the decking with the ice shield....especially if skylights or valleys are involved.

[Rod N]

I left mine on and did a metal roof on top for $2 sq/ft.

[coolreed]

Take the old tiles off.

[dirttracker18]

Originally Posted by NUTTSGT

I've often heard that if the current shingles are in decent shape, you can put a second layer on them. It makes me wonder to myself, if the shingles are in that good of shape, why are you putting new ones on?

Just my 2¢, I'd tear off the old.

This ^^^^^^

Lots of guys go two layers, good guys never do. It is poor practise to layer them. Do it right the first time.

I will also second metal roofing. Easier to instal, lifetime warranty, and looks and performs great.

[SuitorsGarage]

Do it right the first time and strip the old shingles off.
Only a fly by night or hack roofer would do a second layer in my opinion. I worked for a commercial roofing company for 11 years. We didn't do new construction, only re-roofs. We did not specialize in shingles but did plenty of them. Our idea of a shingle job was 100 or so condo/town homes in one shot remove, repair, replace. Never would we do an on over shingle job.
Now I am a self employed contractor. I will do roofs. I always insist on tearing off the old. I don't do it to get the price of the job higher. I do it for the quality of the work. I've ripped my share of roofs with shingles being the easiest to rip and really I could care less if I ever rip another one. Putting a second layer on is taking the easy way out. I won't do it that way if I do a roof. When I'm done with a roof I give a 2yr warranty myself. How do you know what the condition of the deck really is unless you see it for yourself.

Above all think safety! I know it is not an easy thing to do at home sometimes but you can get just as hurt on your own roof as roofing for a living.

[GirlnAgarage]

Strip the old.

[oldgoat]

For the most part I would strip it down for many of the same reasons mentioned like weight and check condition of underlay. I would also say though that if you go to a class 4 shingle with some insurance companies you can get a healthy discount on your homeowners insurance. Yes a metal roof is good, but I know on the old metal roofs that it could get noisey during heavy rain or hail. Also I saw on one policy that you would need to sign a waiver on the appearance of the metal roof for a discount.

[ArkTinkerer]

I've read a lot of opinions on other sites about this but very little to back it up. There are a number of caveats to doing an overlay--shingles can't be curling (mine are not), new shingles need to have the same exposure to lay correctly (can do), and the decking must be in good shape.

I read thru several warantees and there is nothing there that says overlays void the warantee. That said, the warantees on these products stink (prorated) and labor is the big thing.

The concept of inspecting the decking is the only valid issue I have seen. I have been up in the attic and seen the underside as well as walked the roof and all seems solid. I am trying to get this done before I have any issues. My existing shingles are not leaking but some spots have little to no mineral left on them. The ridges are cracking. It could last another couple years but that would risk problems. I'd rather fix it now.

Big savings for the overlay is labor if I do it myself. Also I can go slower--one section at a time--and it would be easier to follow existing courses. Current roof has no drip edges installed, I can order drip edges intended for overlays and actually have a better roof. Biggest concern for me is doing the valleys--I don't like the way the old ones were done -- they just don't look like water would flow right over them.

ArkTinkerer

[5lima30]

Tear off!

[NUTTSGT]

Originally Posted by ArkTinkerer

Big savings for the overlay is labor if I do it myself. Also I can go slower--one section at a time--and it would be easier to follow existing courses. Current roof has no drip edges installed, I can order drip edges intended for overlays and actually have a better roof. Biggest concern for me is doing the valleys--I don't like the way the old ones were done -- they just don't look like water would flow right over them.

ArkTinkerer

If you're worried about the valleys, I believe that is more than enough reason to tear off the old. You may want to inspect to see if there is any damage under the shingles/valley material.

[BD1]

DEFINITELY tear off. That's a lot of weight. Figure how much the new shingles weigh and you will remove old. Don't know your location but if snow load is a concern, tear off.

[KnurledNut]

1. Does the roof sag right now? (From ridge to eave?) Tear off.

2. If you can get it the attic, see how its framed...
then throw a couple numbers in this calculator:
http://www.awc.org/calculators/span/...rcalcstyle.asp
If its inadequate, tear off.

3. If its structurally sound, and you got three tab, you could overlay.
Use a 5" starter course, and a 10" first course to get you running right.

4. Ive tore off numerous roofs with 1, 2, 3 layers. Unless you got 1 million square not much difference honestly.

IMHO anyways...

[darkk]

I never do 2 layers, just personal preference I guess...

[signcrafter]

Originally Posted by ArkTinkerer

I've read a lot of opinions on other sites about this but very little to back it up. There are a number of caveats to doing an overlay--shingles can't be curling (mine are not), new shingles need to have the same exposure to lay correctly (can do), and the decking must be in good shape.

I read thru several warantees and there is nothing there that says overlays void the warantee. That said, the warantees on these products stink (prorated) and labor is the big thing.

The concept of inspecting the decking is the only valid issue I have seen. I have been up in the attic and seen the underside as well as walked the roof and all seems solid. I am trying to get this done before I have any issues. My existing shingles are not leaking but some spots have little to no mineral left on them. The ridges are cracking. It could last another couple years but that would risk problems. I'd rather fix it now.

Big savings for the overlay is labor if I do it myself. Also I can go slower--one section at a time--and it would be easier to follow existing courses. Current roof has no drip edges installed, I can order drip edges intended for overlays and actually have a better roof. Biggest concern for me is doing the valleys--I don't like the way the old ones were done -- they just don't look like water would flow right over them.

ArkTinkerer

Ridges are cracking, don't like the valleys, no drip edge. Sounds like a poor roof, even though you say it is in decent shape. Do yourself a favor and tear it all of and start fresh. You can put down ice dam, drip edge, do the valleys right, etc. Why go over stuff you aren't sure about like the valleys you say you don't like the way they are done.

You can do what you want because it's your roof but any decent roofer would tear it off and start fresh for numorous reasons. I see no reason that a home owner wouldn't want to do the little bit of extra labor to do the job right themselves.

[ArkTinkerer]

I'm in Arkansas. Very few houses here have drip edges--they just run the shingles beyond the edge by about 1". Even fewer ice shields--we are lucky to get one snow a year and its gone in a few days. Roof has no sag and the lines are very straight.

But the roof is old. Its done its thing for at least 20-25 years and I've been here for 14 of those and I want to fix it before its a problem.

Best argument against so far is tear off allows inspection. But I can inspect from the attic for the most part.

Arguments for overlay are labor, cost, convenience.

I appreciate the advice so far but has anyone personally seen a problem on a second layer of shingles if its well installed and the deck is solid?

ArkTinkerer

[RECox286]

We never layered any roof we ever did. Sometimes the deck was in OK

shape, sometimes there were surprises that reared their ugly heads when

the felt was peeled off. Since we live and worked at the shore, we found

a lot of bad flashings, steel, copper and aluminium alike due to the salt,

humidity, and aging of the materials. If the roof shingles are wood to

begin with, normally they as well as the lathe needs to be stripped off

so a proper deck can be applied. Too many factors to consider b/c

the underside of the roof hasn't been looked at in how many years, and

won't be for another how many. While you are at it, consider a 40yr

architect overlay shingle so, like me, you will never have to fool with it

again in your lifetime. Some last thoughts: don't rely on the cheapie stack

pipe flashings. Have a tinknocker make up a proper flashing that folds

over and into the stack. We have seen too many cheapies fail long

before they should. Also, Ice and Fire applied around the whole perimeter

of the roof is an excellent idea, as well as using 30# felt (minimum). I know

that it ups the cost somewhat, but there is nothing like buying a good

insurance policy for the stuff that lives under the roof.

Uncle Bob

[rburke65]

You are adding a lot of weight to that roof system......strip it!

[bczygan]

Originally Posted by ArkTinkerer

I've read a lot of opinions on other sites about this but very little to back it up. There are a number of caveats to doing an overlay--shingles can't be curling (mine are not), new shingles need to have the same exposure to lay correctly (can do), and the decking must be in good shape.

I read thru several warantees and there is nothing there that says overlays void the warantee. That said, the warantees on these products stink (prorated) and labor is the big thing.

The concept of inspecting the decking is the only valid issue I have seen. I have been up in the attic and seen the underside as well as walked the roof and all seems solid. I am trying to get this done before I have any issues. My existing shingles are not leaking but some spots have little to no mineral left on them. The ridges are cracking. It could last another couple years but that would risk problems. I'd rather fix it now.

Big savings for the overlay is labor if I do it myself. Also I can go slower--one section at a time--and it would be easier to follow existing courses. Current roof has no drip edges installed, I can order drip edges intended for overlays and actually have a better roof. Biggest concern for me is doing the valleys--I don't like the way the old ones were done -- they just don't look like water would flow right over them.

ArkTinkerer

Shingling over is plain and simple a cheaper, crappier way to do it. But go ahead and find reasons to talk yourself into doing that if you like. You may end up convincing yourself that you're happy, but people who know what's what will know you took the shortcut. I'm a builder and would never even remotely consider doing that to anyone, friend or enemy. Anything worth doing is worth doing right, or not at all.

[Rust]

Tear it off..and ridge vent is practicly useless without venting at the soffits.

[GirlnAgarage]

ArkTinkerer, you've been given reasons to strip it. If they aren't strong enough for you, it's your roof, by all means do it how you want. But seems like you want a blessing before you go ahead. Here you go - good luck!


If the amount of work/work speed is what's making the layer look like an acceptable compromise (you did say "Also I can go slower--one section at a time--and it would be easier to follow existing courses."), then paying for roofers to get it done at a good working speed would be a plus.

Anyway, do it how you want. It's your house.

[dirttracker18]

You seem to be looking for someone to give you the OK that you can do it.

It's your roof so you do not need anyones blessing. The overwhelming majority on here are saying to do it right and strip it. However you continue to come back and lean towards another layer.

Plain and simple it is the cheap and wrong way to do it. When you have a problem in a 5 years the only way to fix it will be to strip. Do one layer now and you can make small repairs if needed. BTW, drip edge is not just for snow, but any water coming off your roof.

Your roof, your time, make a choice and run with it. You know what most of us would do.

[CodyY]

I'm a roofer in DFW, with an architecture degree.

Strip it. Leave old felt. New 15lb felt over that then Gaf timberline

The insurance companies don't like the additional weight on the rafters. Tear-off costs me a whopping $10 per square. It's worth it.

[CodyY]

Originally Posted by oldgoat

For the most part I would strip it down for many of the same reasons mentioned like weight and check condition of underlay. I would also say though that if you go to a class 4 shingle with some insurance companies you can get a healthy discount on your homeowners insurance. Yes a metal roof is good, but I know on the old metal roofs that it could get noisey during heavy rain or hail. Also I saw on one policy that you would need to sign a waiver on the appearance of the metal roof for a discount.

Best deal in class4 is Owens Corning Weatherguard HP. about $30/sq over a 30yr shingle

[signcrafter]

It sounds like you already have your mind made up and it is your house so do what you want and best of luck to you.

What I don't understand is you ask a question looking for advice and almost everyone advises you to tear it off for various reasons. Yet you seem to keep trying to justify not tearing it off, or at least that is what I get out of your posts. So why ask if you don't want to hear what others are telling you?

[ra42mario]

I Just redid half the roof on my shop (hip roof). We stripped it, you would be surprised by the amount of bad wood that you could never see.

[ArkTinkerer]

I do have a strong bias for not doing the tearoff--I don't think I'm up to it time and labor wise. That means paying to have it done. Big difference in $$$ and might even make me delay the job for a year or two.

Its clear people have a strong bias against it and thats why I ask. I do think inspection is the only valid argument people have presented so far. I discount statements like "Shingling over is plain and simple a cheaper, crappier way to do it. " because it has no info on why its "crappier". What I read agrees with this if the shingles are broke/curling etc. but that is not my roofs condition. I've heard of people doing a bad installation--bad flashing, short nails, bad valleys, etc. But if I pay people I will be subject to the same risk at higher cost. If I do my own overlay, I trust myself to do a good, if slow, job. Knowing WHY an overlay is inherently bad is very important to me in making an informed decision. The WHY seems to be missing from the opinions listed here.

ArkTinkerer

[dirttracker18]

Originally Posted by ArkTinkerer

Its clear people have a strong bias against it and thats why I ask. I do think inspection is the only valid argument people have presented so far.
ArkTinkerer

WEIGHT - have you ever carried a single bundle of shingles?

Higher likelyhood of future leaks

Much higher difficulty of determining location of future leaks.

did I mention the added weight

your aforementioned valley issues

it's poor workmanship

weight

when your underlayer does start to curl, your new shingles will be lifted

added heat to first layer of shingles

weight

[GirlnAgarage]

Originally Posted by ArkTinkerer

The WHY seems to be missing from the opinions listed here.

ArkTinkerer

No, they're not missing. They were written in plain English. You are refusing to acknowledge the importance of the reasons given.

Instead of accusing everyone here of not providing info, you could say "Thanks for the info but I think I'm going to just do the overlay."

[ArkTinkerer]

>>Weight
Read this before, but not too concerned.

>>when your underlayer does start to curl, your new shingles will be lifted
..
>>heat

Thank you! These are two new to me and make some sense. So the underlayer will curl later even though its not exposed? The heat of the underlayer--what is the effect of this? Decking damage, bad seal, cause the curl listed above?

ArkTinkerer

[ArkTinkerer]

Originally Posted by GirlnAgarage

No, they're not missing. They were written in plain English. You are refusing to acknowledge the importance of the reasons given.

Instead of accusing everyone here of not providing info, you could say "Thanks for the info but I think I'm going to just do the overlay."

I apologize if I caused offence. Perhaps I was not clear enough in asking for more detailed reasoning in my posts. I did not mean to "accuse" anyone.

I re-read this thread from the beginning. There are a fair number of posts in this thread that say it is ok or are ambivalent about overlays and my impression was most of those were from people who had done fewer roofs. (One pointed me to a great website with info on this--Thanks!) Some are stridently opposed and they sound like they come from those who do this professionally and do lots of roofs. In my opinion, they didn't give sufficiently detailed reasons. That they have more experience gives more weight to their replies and led me to follow up with more questions.

ArkTinkerer

[Falcon67]

I'll give you one more to confuse you LOL. The open shed at our old property was 16wx22l. Before insurance would write the policy, the agent required that the shed roof be fixed. It had 3 tabs on it that were curling. I started taking it off, and under two layers of gray 3 tab I found these cool green 3 tab shingles. And, they were laying flat, but missing quite a bit of gravel. So - I went over them with the cheapest gray 3 tab shingles I could find at Payless (remember them?) and got the policy written. That was 1997. We sold the house/property in 2010. The house had two roofs during that time due to hail storms and the shed roof had zero. Still looks good. Note that the shed is open in the front and has no ceiling, so roof deck heating was minimal.

On the flip, the house we bought was built in 2001. It has a single layer of standard 20 year gray 3 tabs on it. There were NO upper vents on the roof, just eve vents. (I dunno). First project was to vent the roof. I can still work with the shingles, but I have already replaced a couple from wind damage where the tabs just snapped off. I'd guesstimate the "age" of the roof at about 15 years due to the excessive heat trapped up there by the screwed up venting. They are not curling, but they feel rather fragile.

[NUTTSGT]

The reason the majority of people are telling you to strip it is because of experience. With experience, comes knowing what's the right way and wrong way of doing something.

Enjoy you're roofing project, drink plenty of water (gatorade/powerade), I'd suggest you wear tennis shoes as they are easier on the shingles you have already put down and stay off the roof when it gets really hot, you'll distort/tear your new shingles.

[SuitorsGarage]

Your nails are going to be going through more shingle material and are not going to hold the shingle down as well as if you stripped the roof making it more prone to a blow off. Also more prone to have a nail pop (lift).

Your shingles may look like they are not curled at all but if they are in the least your new shingles won't be sitting as flat as if you tore off your old roof. Then your new shingles will curl easier and more.

On your valleys that you don't like the way they are shingled. With an overlay the leading edge of the valley shingles that you are not happy with will still be exposed.

Time wise. You do not need to strip the whole roof all at once and bang shingles until you are done. Depending on how your roof is cut up you can probably rip and roof an area at a time. The time you spend actually ripping the roof and getting rid of it is a lot less than applying the new roof.


Roofing is kind of a sucky job and I'm sure that everyone (like me) was just trying to get you to do the best job possible the first time to avoid any problems with the best craftsmanship.

[BD1]

Just curious, what centers are your roof rafters on ? Are they trusses out of 2/4's ? What is the existing sheeting thickness and material type ? Check thickness by looking at roof vents.

[ArkTinkerer]

Rafters not trusses. 2x6 with 24" spacing. 1" (3/4" finished thickness) lapped pine for decking.

ArkTinkerer

[bob15]

Art, I counted (quit about 2/3 down) 7 people tell you WEIGHT. Yet you still ask for reasons. Here is another, you'll help keep the land-fill people happy by stripping the roof.

You have 2x6 rafters 24"OC, strip it.

What state do you live in?

[Zeke]

Originally Posted by ArkTinkerer

I appreciate the advice so far but has anyone personally seen a problem on a second layer of shingles if its well installed and the deck is solid?

No. But the roof will look lumpy. If that is not an issue, go ahead, IMHO. The worst overlay is fiberglass 3 tab over wood shingle. I can't stand that. Architectural fiberglass over 3 tab should actually look fine. Here in SoCal we don't get to do overlays anymore. We have to sheet the roof for horizontal shear (even though the sheathing is not truly horizontal, it creates rotational shear).

What's wrong with the valleys? Are they woven or is there a pan? You can lay in a valley pan if there isn't one. Lay it right over the weave. You might want to cut the weave down the valley line.

[ArkTinkerer]

Originally Posted by bob15

Art, I counted (quit about 2/3 down) 7 people tell you WEIGHT. Yet you still ask for reasons. Here is another, you'll help keep the land-fill people happy by stripping the roof.

You have 2x6 rafters 24"OC, strip it.

What state do you live in?

Arkansas

Based upon the online calculators I should be able to handle a second layer of shingles and about 6" of wet snow which is beyond the worst I have seen here in 20+ years.

Thinking about stripping it because of the comment about "nail pops". Those I have seen here even with single layer of shingles. If a second layer makes this more likely it would actually be "probable" here. Don't know the cause but it happens on about a third to half the houses I've seen when the roofs age. Anyone from the sun belt seen issues with this even without overlayed shingles?

ARKtinkerer

[HarleyArley]

I can't give you an example of a problem due to putting on a second roof, but I can assure you it is not wrong or crappy.

I grew up doing roofing, siding and gutters in the Cincinnati area. My grandfather ran a roofing business, my father roofed as a side income, and I grew up from about age 8 on their jobs and did about 2 dozen myself while in high school. Over those three generations I have never heard of a problem due to roofing over an existing layer of shingles which were sound. Every home owner had our business card and our absolute assurance that any problem would be addressed to their satisfaction. We would periodically get a call back... maybe one every 3-4 years due to step flashing or something similar that didn't seal right, but I can never recall an issue as a result of putting a roof on over an existing roof. If the existing roofing was in bad shape or the homeowner requested it we'd tear it off, but the vast majority of our re-roofs went on over existing roofs. However, two roofs max was our policy. Due to roof loads, we never put on a third one.

I have no idea why the majority of the folks here are so nervous about a second layer of roofing.

I hope this helps.

[sirsloop]

I've done both ways and didn't live in the place long enough to ever know the difference. I bought my current house with 2 layers already on it. No biggy, IMHO. I guess next time I do the roof I gotta get a dumpster and pull em

[signcrafter]

Originally Posted by ArkTinkerer

Rafters not trusses. 2x6 with 24" spacing. 1" (3/4" finished thickness) lapped pine for decking.

ArkTinkerer

I would not ever do a layover with 24" center rafters due to weight. How many square roof do you have?

The problem with not tearing off and just going over is just because the shingles aren't curling doesn't mean they are in good shape. When you do a new roof you put tar paper down and then the shingles have tar strips that seal to the tar paper. If you just go over the top of the old shingles you are trying to seal to old shingles that may not be in the best condition. Your shingles may look great but they might actual not be good for laying new shingles on.

The number one reason is you will never get as good of a seal going over old shingles as you would by starting on a fresh, clean, flat surface. You may get a decent seal but you won't get the best seal you can if you start fresh. Things like moisture creating algea and mold, wind pull up, water leaks, etc. Also when you try and go over an existing roof the shingles will not be going down on a flat surface like they are designed to do so they can actually "tear" after a few years of settling.

[dirttracker18]

Originally Posted by HarleyArley

I have no idea why the majority of the folks here are so nervous about a second layer of roofing.

It was common practise 30 years ago but has fallen out of favor.

That is no longer the case. The labor cost to strip is minimal in the overall reroof.

Best practise now is to strip and instal new products under the shingles and inspect. It is now also common to find a shorter lifespan when layered.

If you plan to keep the house you strip and reroof. If you are going to sell in the near future layering is common to "get by."

[HarleyArley]

Originally Posted by signcrafter

When you do a new roof you put tar paper down and then the shingles have tar strips that seal to the tar paper. .

Ummm, the only course of shingles that the tar strip seals to the tar paper is the starter course. Everything else is new shingle to new shingle.

[HarleyArley]

Originally Posted by HarleyArley

Ummm, the only course of shingles that the tar strip seals to the tar paper is the starter course. Everything else is new shingle to new shingle.

Actually that isn't correct either... the tar strips are on top and NONE of them seal to the tar paper.

[HarleyArley]

Originally Posted by dirttracker18

It was common practise 30 years ago but has fallen out of favor.

That is no longer the case. The labor cost to strip is minimal in the overall reroof.

Best practise now is to strip and instal new products under the shingles and inspect. It is now also common to find a shorter lifespan when layered.

If you plan to keep the house you strip and reroof. If you are going to sell in the near future layering is common to "get by."

I cannot comment on current best practice as I have not roofed professionally in 20 years. However, I have torn off re-roofs my grandfather did after 25+ years on at least two occasions I can recall. My father and I did the jobs when the customer called my grandfather who'd originally roofed the house asking who he'd recommend.

The re-roofs seemed to hold up just fine back then. Its possible that the shingles aren't the same as the used to be. I'm just passing on my experience.

[dirttracker18]

Originally Posted by HarleyArley

The re-roofs seemed to hold up just fine back then. Its possible that the shingles aren't the same as the used to be. I'm just passing on my experience.

That is a very good possibility as nothing seems to be built as good as it used to be

[bczygan]

Shingles HAVE changed. They used to be asphalt based and are now FG. Also lighter weight.
BTW, It is fun, quick and easy to strip a roof. I haven't heard a good reason not to.

[Zeke]

Your kind of fun is strange.

The funniest thing about this whole thread are the comments about not putting a 2nd layer over a bad roof (of course not) but it seems like they were saying only over a good roof.

Who would put a new roof over a good roof?

[olytdi]

Originally Posted by zeke

your kind of fun is strange.

The funniest thing about this whole thread are the comments about not putting a 2nd layer over a bad roof (of course not) but it seems like they were saying only over a good roof.

Who would put a new roof over a good roof?

exactly!

[HarleyArley]

Originally Posted by Zeke

Who would put a new roof over a good roof?

By good roof, I mean one that isn't leaking yet. Most roofs will keep out water long after their physical appearance says they are shot. Most home owners look for a new roof before a leak occurs. Obviously, any area with a know leak needs serious inspection to ensure the decking is still sound and will not cause future problems.

However, if the roof has not leaked, a second layer of shingles isn't the end of the world in my opinion. Even if the original 3 tabs are curled in places it still works. You simply adjust your courses to nail though the tabs of the old roof.

All that said, there are certainly only a few disadvantages to tearing off the old roof. They include waste disposal, labor, and the risk of serious damage to the home if a serious storm comes up before the roof can be restored. None are show stoppers. A tarp and a zero risk mentality should deal with the storm angle. The rest is just a bit of time and money.

So what would I do if I planned on staying for 30+ years? Barring serious financial limitations that prevented it, I'd tear it off and put all new materials in from drip edge, to ice shield, to felt, to shingles, to ridge vents, to vented soffits. It may not be essential, but its the safer course of action. If it went to crap early, I could say without a doubt it wasn't for lack of trying.

[Rust]

lol
This thread reads more like a philosophy class than a thread for advise on roofing.
Procrastination is usually backed up with alot of words.



At this point, I'd just tarp it.
If you triple then up you can get at least five more years. Not to mention the cash you'd save...





I drive by this house every day.
It started with one shingle blown off a few years ago. Someone attempted to repair it, hence the kickers, and never went back. I took this photo today, just for this thread.

[kwb]

For what you can get a decent roofing crew to do a roof for compared to your buying power of roofing (little to none) skip the DIY, have pro's come in strip and reroof and they will be out of there in a day or two.

Guys that did my house (44 square) were only about 35% over the material price that I could have gotten for a 30yr roof and they did it with lifetime (50yr) material. All I had to lift was a pen to write a check.

My brother when he built his shop (20square) went for 30yr materials and it was less than a grand more than what he had in a bid for the materials and was done in half a day.

NFW would I ever do my own roofing beyond a garden shed again after realizing this.

[El Barto]

Originally Posted by bczygan

Shingles HAVE changed. They used to be asphalt based and are now FG. Also lighter weight.
BTW, It is fun, quick and easy to strip a roof. I haven't heard a good reason not to.

Hmmm, I'm just checking your location to see how I can get you to come to my house for a weekend.

[Zeke]

Originally Posted by kwb

For what you can get a decent roofing crew to do a roof for compared to your buying power of roofing (little to none) skip the DIY, have pro's come in strip and reroof and they will be out of there in a day or two.

Guys that did my house (44 square) were only about 35% over the material price that I could have gotten for a 30yr roof and they did it with lifetime (50yr) material. All I had to lift was a pen to write a check.

My brother when he built his shop (20square) went for 30yr materials and it was less than a grand more than what he had in a bid for the materials and was done in half a day.

NFW would I ever do my own roofing beyond a garden shed again after realizing this.

You must live in a state where insurance is cheap or non existent. In CA, roofer workers comp runs over 100 %. That means I pay 20 bucks an hour to the roofer and over 20 to the ins co. Then I pay his SDI, SS and UI. He gets 14 net after withholding; he costs me 50/hr. I charge 100 and make little because 40%+ of my income goes to taxes and SET.

[kwb]

Washington by most standards is not cheap for insurance not sure the state industrial rate for roofers but it was listed as very high for construction in general in a recent initiative that was up for vote that would have changed the system by a long shot.

I just know what I had for materials bids and I know what I paid my contractor - who checked out for insurance, bond, etc before I selected them.

[SARG]

As many have already said ... strip it down and do it right ..... and I would also suggest GAF architectural shingles only.

They seal the best... they seal the fastest .... and they last the longest.

[ArkTinkerer]

Originally Posted by kwb

For what you can get a decent roofing crew to do a roof for compared to your buying power of roofing (little to none) skip the DIY, have pro's come in strip and reroof and they will be out of there in a day or two.

Guys that did my house (44 square) were only about 35% over the material price that I could have gotten for a 30yr roof and they did it with lifetime (50yr) material. All I had to lift was a pen to write a check.

My brother when he built his shop (20square) went for 30yr materials and it was less than a grand more than what he had in a bid for the materials and was done in half a day.

NFW would I ever do my own roofing beyond a garden shed again after realizing this.

Pricing is quite different here. About 30 square to the job. About $3k for shingles $4.5K for labor for tear off/reroof. Nothing really special--single story, moderate slope, one chimney, about 6 vents thru the roof. Had two quotes and they are similar.

I have to work more hours to clear 4.5K after taxes than I think it would take me to do the job myself. If I do an overlay its a no-brainer--I'd do it myself. Tear off leaves the roof exposed for a longer period of time or makes it harder to do in sections on Saturday mornings.

Still researching the nail pop and sealing issues of an overlay.

ArkTinkerer

[WVBrady]

Originally Posted by ArkTinkerer

.... Tear off leaves the roof exposed for a longer period of time or makes it harder to do in sections on Saturday mornings...

I'm planning on removing mine in sections, just what I can get recovered that day (or longer non-rainy period).

[Zeke]

Originally Posted by WVBrady

I'm planning on removing mine in sections, just what I can get recovered that day (or longer non-rainy period).

That is a very good way to go. Strip and lay down the underlayment for an entire shed section. Only too much sun or a nasty storm will mitigate that plan. do 'em one at a time and run the ridge last. Not much rain falls on the ridge.

[bczygan]

I don't know if the question was asked and answered, but the first questions should have been "Have you done this kind of roofing before?" Is it a simple roof? Do you have any "grunt" help? Are you in good physical shape and in the mood for this kind of physical work?
Are you going to hand nail or use a power nailer?
Are you going to hump the bundles up or have them roof delivered?
Is it all 1 story and low slope?
What's the weather?
Have you got adequate tarps for the debris and to cover in case of rain?

Your posts and detailed questions seem to indicate that you are inexperienced with roofing and wanting to learn which is good. So take the expert advice offered here.

If it is just you doing the work, you can do it, but plan to work in stages.
It is monotonous, hot and physical work.
Stripping is physical but satisfying as you see a big change as you remove the old shingles. Pulling stray nails will be tedious. You will then see the decking boards and find the ones that need replacing. And there will be some. You will also see all the vent and flashings and have the opportunity to make any changes to venting or flashing. Also, you will have the opportunity to use ice and water shield and a good underlayment.
You will work way slower than an experienced crew. If you can make more per hour in your work, you won't save money, but if you are using free time, it pays to do it yourself. You will be able to guarantee quality.

As far as having it done, there are crews and there are crews. You will spend time and effort finding the right one. Roofing is like carpet install, a trade where some contractors can make a bunch by using the worst (And cheapest) crews and cutting corners to make the most money. A friend ran 2 crews. One could work alone. The other was dragged out of bars and he had to watch them every minute.

On a sizable roof you will be so tired of roofing by the end, that you will never want to look at another one. But you will have the exhausted satisfaction of a big job well done.

What color are you planning on?
3 tab or dimensional?
Closed cut valleys?
Place your drip edge so it is 1/2" out from the edge of the fascia.
Do you know which way the prevailing winds are so you know which way to run the cap shingles on your ridges?

[djd99]

It's unbelievable to me that there are so many people willing to spend others money so quick. I'm still old school and would have absolutely no issues with throwing a overlay on with Architectural shingles. If your current roof isn't leaking and you know your deck is solid, really you could get another 30 years out of a overlay. As a fact I'm going to do the same thing in the next 5 years. I know several of my friends I helped overlay with their house and none of them leak. Do what you want to do Is all that matters anyway.

[CodyY]

Originally Posted by djd99

It's unbelievable to me that there are so many people willing to spend others money so quick. I'm still old school and would have absolutely no issues with throwing a overlay on with Architectural shingles. If your current roof isn't leaking and you know your deck is solid, really you could get another 30 years out of a overlay. As a fact I'm going to do the same thing in the next 5 years. I know several of my friends I helped overlay with their house and none of them leak. Do what you want to do Is all that matters anyway.

You're Old school.
I'm a construction manager for a roofer with an architecture degree or three.

Strip it, my cash price during storm season is $200 a square for O-C or GAF "lifetime", including drip edge and penetrations. I can buy the material for your job for almost HALF what you can. It would be done in a day or less and ya don't have to fuck with it.

Or risk your old ass falling off the ladder and having a 60lb bundle land on you

[johncarton]

i think Big Poppa said right......

[wouldworker]

I have had a roof replaced due to hail damage 2 different times. Each time the insurance adjuster said to tear off the old roof--adjusters said it is common practice in the industry at this time.

[CodyY]

Originally Posted by wouldworker

I have had a roof replaced due to hail damage 2 different times. Each time the insurance adjuster said to tear off the old roof--adjusters said it is common practice in the industry at this time.

Because of the additional weight on the rafters.

[6768rogues]

Our building code does not allow for more than two layers of shingles. I remove them even if there is only one layer. A second layer will have its life span reduced by about 25%. Then again, if you can legally put down a third layer and you will not be staying in the house for more than 10 years or so, it will be a lot cheaper.