[wmarazita]

Hello,
I have a cabin at 6000 feet that needs a new roof. We would like a dimensional asphalt shingle (something like Certainteed Presidential) for the new roof. The current roof is one layer of a lower quality, non dimensional asphalt shingle. The roof does not currently leak or have any noticeable water damage. We did get a very tiny leak a couple years ago during a very heavy wind and rain storm. My belief is that the water was being blown up under some flashing, which I nailed down better. No leaks since. We get some snow each year that may accumulate to a foot on the lower sloped roof over the front porch, but usually it is gone within a few days. We have had three roofers out and each have said that they would recommend installing new roofing shingles over the old roofing shingles since it is not leaking. They said they would do a tear-off and new roof if I wanted, but it would be about double the cost.
A few questions for the group:
1. Is a "roof over" an acceptable roofing solution for me in this situation?
2. If so, I will probably do the "roof over" myself. I am perfectly capable of the physical labor and have the tools as long as the group can walk me though the particulars and any "gotchas".
3. In a "roof over" should I put down new felt and drip edge over the current roof? Or do I just put new roof directly on old shingles?
4. Do I use a starter strip, as usual with asphalt shingles? if going directly on the old shingles.
5. Do I follow the exact shingle spacing if applying directly over the old shingles.


As usual. there are many more questions that I don't know to even start asking.


Thanks
Bill

 

[dj3]

If you re-roof, might as well do it to your city/county code. Agree?
First, find out if the building dept allows 2 roofs - you can just call without giving your name. In my city they don't allow it.
Then you have to make sure that your rafters can handle the weight.
You said that the old roof is not leaking, but then you said you "need to re-roof".
When you clear all of these questions and ready to start, we can help.

 

[jmon]

Hello,
I have a cabin at 6000 feet that needs a new roof. We would like a dimensional asphalt shingle (something like Certainteed Presidential) for the new roof. The current roof is one layer of a lower quality, non dimensional asphalt shingle. The roof does not currently leak or have any noticeable water damage. We did get a very tiny leak a couple years ago during a very heavy wind and rain storm. My belief is that the water was being blown up under some flashing, which I nailed down better. No leaks since. We get some snow each year that may accumulate to a foot on the lower sloped roof over the front porch, but usually it is gone within a few days. We have had three roofers out and each have said that they would recommend installing new roofing shingles over the old roofing shingles since it is not leaking. They said they would do a tear-off and new roof if I wanted, but it would be about double the cost.
A few questions for the group:
1. Is a "roof over" an acceptable roofing solution for me in this situation?
2. If so, I will probably do the "roof over" myself. I am perfectly capable of the physical labor and have the tools as long as the group can walk me though the particulars and any "gotchas".
3. In a "roof over" should I put down new felt and drip edge over the current roof? Or do I just put new roof directly on old shingles?
4. Do I use a starter strip, as usual with asphalt shingles? if going directly on the old shingles.
5. Do I follow the exact shingle spacing if applying directly over the old shingles.


As usual. there are many more questions that I don't know to even start asking.


Thanks
Bill

Imo, yes, you can do a roof over, as long as you have only one layer of shingles. If there is more than that then you need to do a tear off. It's done all the time. Plenty of videos out there showing you how to do this step by step.

 

[Old Thomas]

Most codes based on the IRC allow 2 layers. You would be adding about 2 lbs. per square foot, not a concern. Metal edge pieces are for reroof so they are larger and will cover the old edges. One layer lasts longer and looks better than two layers. If you are physically able to do the roof, strip it and start over. Buy a shingle eater tool, you will be surprised how easy it is to strip it. I am old and I can strip a roof easily. It peels right off. Start by removing the caps and work top down, one face at a time, then shingle it. Unless you are planning to get out in 10 years or less, strip it. In a couple of hours you can have 10 squares on the ground.

 

[Marson]

Hello,
I have a cabin at 6000 feet that needs a new roof. We would like a dimensional asphalt shingle (something like Certainteed Presidential) for the new roof. The current roof is one layer of a lower quality, non dimensional asphalt shingle. The roof does not currently leak or have any noticeable water damage. We did get a very tiny leak a couple years ago during a very heavy wind and rain storm. My belief is that the water was being blown up under some flashing, which I nailed down better. No leaks since. We get some snow each year that may accumulate to a foot on the lower sloped roof over the front porch, but usually it is gone within a few days. We have had three roofers out and each have said that they would recommend installing new roofing shingles over the old roofing shingles since it is not leaking. They said they would do a tear-off and new roof if I wanted, but it would be about double the cost.
A few questions for the group:
1. Is a "roof over" an acceptable roofing solution for me in this situation?
2. If so, I will probably do the "roof over" myself. I am perfectly capable of the physical labor and have the tools as long as the group can walk me though the particulars and any "gotchas".
3. In a "roof over" should I put down new felt and drip edge over the current roof? Or do I just put new roof directly on old shingles?
4. Do I use a starter strip, as usual with asphalt shingles? if going directly on the old shingles.
5. Do I follow the exact shingle spacing if applying directly over the old shingles.


As usual. there are many more questions that I don't know to even start asking.


Thanks
Bill

If you are going over one layer of three tab shingles that are nice and flat to a roof deck that is in good condition, then IMO a roof over is acceptable. I have done it myself.


No need for felt in this situation. Drip edge is up to you, depending on the status of the current drip edge. You would probably want to demo the bottom row of shingles so they don't show.



I would use starter strip. You want to shed the water out over the drip edge.



I don't know about the shingles you are using and what kind of shingles you are going over but typically, architectural shingles have a different exposure and size than the old three tabs, so no, you don't match them. They are also thick enough that the ridges from the different course of shingles won't show through.



You'll want to make sures your nails are long enough to penetrate the roof deck.

 

[wmarazita]

If you re-roof, might as well do it to your city/county code. Agree?
First, find out if the building dept allows 2 roofs - you can just call without giving your name. In my city they don't allow it.
Then you have to make sure that your rafters can handle the weight.
You said that the old roof is not leaking, but then you said you "need to re-roof".
When you clear all of these questions and ready to start, we can help.

Yes, would definitely want to do it to code. My area follows California Building Code which allows two layers of this material in my circumstance. I'm no too worried about the rafters since this material is so light. Is this really an issue? Roof is 40 years old and the "sand" is all coming off the shingles. I want to do it BEFORE it starts leaking.

 

[wmarazita]

If you are going over one layer of three tab shingles that are nice and flat to a roof deck that is in good condition, then IMO a roof over is acceptable. I have done it myself.


No need for felt in this situation. Drip edge is up to you, depending on the status of the current drip edge. You would probably want to demo the bottom row of shingles so they don't show.



I would use starter strip. You want to shed the water out over the drip edge.



I don't know about the shingles you are using and what kind of shingles you are going over but typically, architectural shingles have a different exposure and size than the old three tabs, so no, you don't match them. They are also thick enough that the ridges from the different course of shingles won't show through.



You'll want to make sures your nails are long enough to penetrate the roof deck.

I will need to take a closer look and see if there is drip edge up there. If I add new drip edge, do I attach on top of the current shingles? Or would I try to get in under the current shingles?

 

[Nealtw]

Will step flashing be a problem for any of this, if there is any?

 

[wmarazita]

Will step flashing be a problem for any of this, if there is any?

Hi,
If this question is for me, I'm sorry but I don't understand it.
Bill

 

[Nealtw]

Hi,
If this question is for me, I'm sorry but I don't understand it.
Bill

Do you have step flashing where a roof runs up beside a wall.

 

[wmarazita]

Do you have step flashing where a roof runs up beside a wall.

Oh got it.
Yeah, I may. I will need to check.
I was thinking that if I reroofed over old shingles that I wouldn't have to deal with putting down new flashing. Is that not correct?
Thank you

 

[Nealtw]

Oh got it.
Yeah, I may. I will need to check.
I was thinking that if I reroofed over old shingles that I wouldn't have to deal with putting down new flashing. Is that not correct?
Thank you

Now the question is for the other guys. :biggrin2:

 

[PatChap]

Oh got it.
Yeah, I may. I will need to check.
I was thinking that if I reroofed over old shingles that I wouldn't have to deal with putting down new flashing. Is that not correct?
Thank you

Details are where 2nd layers tend to be problematic.
If you have any sidewalls, at a minimum you need to ensure you get underneath the first step flashing so the water drains onto the new roof and not under it.

 

[carpdad]

That image shows step flashing weaved with shingles. They work together so water from one shingle flows to one flashing to one shingle, etc. There's always a chance that water flows sideways, bypassing the flashing. So underlayment is important also. These parts wear out and may fail before the life of new shingles.

Where is the cabin and what do you want from it? If keeping with neat neighbors, you should tear off. If not and flat and straight lines are not so important, you can roof over with new flashing over old. Using ice shield as well as new weather barrier, even if just tarpaper over old shingles would be the right choice for me. They are insurance layer over insurance layer and things which should not be skipped. Ice barrier does not have to stick to the roof sheathing. I would think old drip edge will be serviceable, since they are usually aluminum and esp eave drip edge is for kicking water away from the facia than keeping the area dry. Overhang the new shingles at least one inch with the starter shingle which can be upside down shingle, more if how it looks is ok with you. But don't encroach into the gutter too much. This is time to add gutter covers too.


Learn the best practice for roofing (which is about the same as code/rules). Your roofer/inspector may say add ridge vent but your house may not need it, example.

 

[wmarazita]

Details are where 2nd layers tend to be problematic.
If you have any sidewalls, at a minimum you need to ensure you get underneath the first step flashing so the water drains onto the new roof and not under it.

got it. thanks

 

[wmarazita]

That image shows step flashing weaved with shingles. They work together so water from one shingle flows to one flashing to one shingle, etc. There's always a chance that water flows sideways, bypassing the flashing. So underlayment is important also. These parts wear out and may fail before the life of new shingles.

Where is the cabin and what do you want from it? If keeping with neat neighbors, you should tear off. If not and flat and straight lines are not so important, you can roof over with new flashing over old. Using ice shield as well as new weather barrier, even if just tarpaper over old shingles would be the right choice for me. They are insurance layer over insurance layer and things which should not be skipped. Ice barrier does not have to stick to the roof sheathing. I would think old drip edge will be serviceable, since they are usually aluminum and esp eave drip edge is for kicking water away from the facia than keeping the area dry. Overhang the new shingles at least one inch with the starter shingle which can be upside down shingle, more if how it looks is ok with you. But don't encroach into the gutter too much. This is time to add gutter covers too.


Learn the best practice for roofing (which is about the same as code/rules). Your roofer/inspector may say add ridge vent but your house may not need it, example.

this all makes sense.
I will need to get up there and take a look at all of the flashing.
My feeling is that these roofers that I had met with were just planning to go right over the top with the new roof rather than put in new step flashing, but I might by wrong. If there is step flashing, it would be under wood siding, so that would have to come off in order to flash those areas properly. At that point, it seems like a tear off would be the way to go.

 

[Colbyt]

Never do a nail over. Tear it off and do it right. Fix any problems found while they are small.



Depending on the existing step flashing it may or may not be suitable for reuse. It depends on what was installed.


For a 'as secure as possible' a nail over should have new flasing. Else, the water gets in and under your new shingles.