Recommendations for roof type when reroof

3526 Views 24 Replies 7 Participants Last post by jagans, Dec 7, 2012

daluu

Discussion Starter · Dec 4, 2012 (Edited)

2

I have a roof with both 4:12 and 2:12 slopes. In other earlier posts, folks have suggested I look into other roof types meant for low sloped roofs.

But what should the overall roof system be includng the 4:12 slope? One single roof system meant for low slope used for the higher slope too?

Or have a mix of normal and low slope roofing types and integrate/join appropriately at the valleys?

The current roof is all asphalt shingle across slopes.

Attached is a photo of my roof from Google maps overhead view. I've marked the slopes of the roofs. Area A is a valley where the valley is very close to plumbing vent pipes. On reroof either need to move vent pipes further out or make custom valley to properly seal the vent flashings with the valley flashing. Attic there is small, so moving pipes will have to do from the roof top after old roof torn off. Area B is a hog valley where 4:12 pitch roofs meet a 2:12 roof.

I can post addiitonal photos from side or down below view if needed.

So seeing the photo(s), what kind of roofing do you recomment? In terms of whole roof or what on which slope roof (if a mix).

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1985gt

· #2 · Dec 4, 2012

You could mix them up, 4:12 shingles 2:12's being another product or you can put the same product on the 4:12's as 2:12's.

Any single ply membrane EPDM,PVC,TPO would be fine, a Self adhered modified or a torch down would be fine too, A hot asphalt would work but on a 4:12 the roofer would need to know what he is doing.

Actually on the whole thing the roofer better know what he is doing, the valleys would be an increased concern when using two different types of materials.

Grumpy

· #3 · Dec 4, 2012

You could mix up the roof like GT said or just cover the entire roof with a low slope membrane. There are a few membranes with printed shingle patterns. But first thing first, shoot the Architect in the face! It should be a requirement that these guys work in the trades before they can start designing chit.

Personally speaking if I were to mix it up, I would be recommending a granulated torch applied modified bitumen in the 2/12 areas and a good quality fiberglass/asphalt shingle in the steep slope areas. http://reliableamerican.us/articles/choosing-a-shingle.html Having said that, if I had my way I may actually propose one of the shingle patterns PVC membranes and simplify the entire project.

1985gt

· #4 · Dec 4, 2012

I agree with grumpy. If it was mine I would do a low slope membrane over the whole thing or a granulated mop down, *IF* I was doing it my self, I don't know I if I would trust others doing a mop down on this design. Possibly with a shingle PVC or even a TPO or PVC with standing seam "battens" welded on. The PVC with the battens will be very expensive but it actually looks very nice.

daluu

Discussion Starter · #5 · Dec 4, 2012

1985gt said:
I agree with grumpy. If it was mine I would do a low slope membrane over the whole thing or a granulated mop down, *IF* I was doing it my self, I don't know I if I would trust others doing a mop down on this design. Possibly with a shingle PVC or even a TPO or PVC with standing seam "battens" welded on. The PVC with the battens will be very expensive but it actually looks very nice.

1985gt, can you provide some photo references for shingle PVC and PVC with battens? Would like to know what they look like. Also for shingle PVC, do those flake off granules like asphalt shingles do over time?

daluu

Discussion Starter · #6 · Dec 4, 2012

Grumpy said:
Personally speaking if I were to mix it up, I would be recommending a granulated torch applied modified bitumen in the 2/12 areas and a good quality fiberglass/asphalt shingle in the steep slope areas. http://reliableamerican.us/articles/choosing-a-shingle.html

FYI, the mod bit was proposed by one roofer, but only at the hog valley (area B) with rest using asphalt shingles. But that was also because in all my reroof inquiries, when asked what kind of replacement roof, I just said shingles. Though I assume a really good roofer may suggest alternatives like you guys do, but I haven't met one roofer (in my area) who actually did suggest those. Not sure why...(price? inexperience? popularity of shingles in my area so they specialize/focus on that?)

1985gt

· #7 · Dec 4, 2012

Look at GAFs web site for the batten style roofs. Ill have to do some digging for the shingle print its been awhile since i seen them. Mod bit would be a good option for the total roof. The valleys on that woupd be one of the best. Ill do some looking tomorrow when im in the office.

AndyWRS

· #8 · Dec 5, 2012

I like the modbit for the low slope and shingles for the 4/12 idea.

The low slope single ply on the whole thing would work also which has been mentioned. I would be concerned about the installation contractor first, you want someone who knows what they are doing no matter what direction you choose.

daluu

Discussion Starter · #9 · Dec 5, 2012

AndyWRS said:
I would be concerned about the installation contractor first, you want someone who knows what they are doing no matter what direction you choose.

How might a homeowner inexperienced with roofing best figure out qualifications of a contractor? Checking their license status and any BBB complaints is a start, but figure that's not enough.

Grumpy

· #10 · Dec 5, 2012

http://www.traditionsclassics.com/ Look at the IB traditions. You have to be a certified installer to even buy the stuff.

Here is a link on hiring your contractor: http://www.reliableamerican.us/articles/hire-your-contractor.htm

Search their reputation online. The BB is a good source to see if they have complaints, don't bother with their silly rating system. If they have alot of complaints, it's a gamble. Also simply google their company name and see what comes up. Perhaps google "rofoers name problems" or "roofers name complaint" see what comes up. Heck google the estimator by name as well. See if he is bragging about his more recent con on his facebook page, or maybe shooting up heroien on his twitter account.

See some of his finished work. Talk to home/property owners.

1985gt

· #11 · Dec 5, 2012

http://www.gaf.com/Roofing/Commercial/Products/Single_Ply_Roofing/EverGuard_TPO_Single_Ply_Membranes/EverGuard_TPO_Accessories

Link to the GAF website the standing seam profile is about 1/2 down the page.

Talk to the contractors customers, once you have a couple narrowed down ask them for references. If they are unwilling to provide any, then simply move along, ask to check out other project similar to yours you can actually go see. The BBB is not really a reliable source, people can pay for a better rating and anyone can make a complaint against a contractor. On site visits and references is where it's at.

Windows on Wash

· #12 · Dec 5, 2012

+1

Have you considered metal?

jagans

· #13 · Dec 6, 2012 (Edited)

Dont Mix

Steep (water shedding roofs) stop at 3/12. Anything under 3/12 is considered low slope.

HOWEVER. I have seen a lot of shingle roofs installed at 2/12 successfully but you need to do the following:

Install ice dams flashing over the entire roof, and double it in the valleys 6 feet out in both directions. make all laps 6 inches and roll in.

Move vent pipes up out of the valleys, That is just plain dumb.

Only use 3 tab shingles, not architectural, as they present less resistance to wind blown rain.

cut the exposure down to 4 inches not 5. Hand nail.

Use gable end vents not ridge vents

Your roof wont leak.

SIngle ply, metal or batten types can be used if you are rich, but all of these bring other things into play. You will really hear rain hitting metal, and snow slides off and crushes stuff. PVC and TPO will look like crap in short order because it builds up static electricity and attracts dirt. Snow will slide off these too, crushing things.

The other options will also cost a lot more than shingles.

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1985gt

· #14 · Dec 6, 2012

jagans said:
Steep (water shedding roofs) stop at 3/12. Anything under 3/12 is considered low slope.

HOWEVER. I have seen a lot of shingle roofs installed at 2/12 successfully but you need to do the following:

Install ice dams flashing over the entire roof, and double it in the valleys 6 feet out in both directions. make all laps 6 inches and roll in.

Move vent pipes up out of the valleys, That is just plain dumb.

Only use 3 tab shingles, not architectural, as they present less resistance to wind blown rain.

cut the exposure down to 4 inches not 5. Hand nail.

Use gable end vents not ridge vents

Your roof wont leak.

SIngle ply, metal or batten types can be used if you are rich, but all of these bring other things into play. You will really hear rain hitting metal, and snow slides off and crushes stuff. PVC and TPO will look like crap in short order because it builds up static electricity and attracts dirt. Snow will slide off these too, crushing things.

The other options will also cost a lot more than shingles.

Ice and water shield the whole roof and dropping the exposure rate on the shingles adds a significant cost to the roof. Putting it up there with a reliable low slope system.

Reasons not to install shingles: Voids warranty, product not ment for low slopes, will wear out 2X or more faster on low slope roofs.

Reactions: 1

daluu

Discussion Starter · #15 · Dec 7, 2012

jagans said:
Install ice dams flashing over the entire roof, and double it in the valleys 6 feet out in both directions. make all laps 6 inches and roll in.

Only use 3 tab shingles, not architectural, as they present less resistance to wind blown rain.

Use gable end vents not ridge vents

Thanks jagans for a different opinion on the matter.

What is ice dams flashing? Is that separate/different from ice & water shield barrier or same thing?

Current roof is using 3 tab shingle instead of architectural I believe. It also has gable end vents (on the 4:12 slope) and not ridge vents, the low slopes are open beam ceilings below, no attic, so no venting on those (apparently no soffit vents either, don't know if they're needed for that or not). The 4:12 slopes also have eyebrow vents in addition to the gable vents.

daluu

Discussion Starter · #16 · Dec 7, 2012

1985gt said:
Reasons not to install shingles: Voids warranty, product not ment for low slopes, will wear out 2X or more faster on low slope roofs.

Does installing shingles really void warranty? The roofers who gave me quotes plus looking up one manufacturer's installation document on shingles online (forget exact site/URL) state that if you install the shingles properly, it will be warranteed by the manufacturer. And the proper installation for 2:12 low slope roofs call for 2 layers of felt underlayment (and I think some may call for ice & water barrier at the lower end of roof).

Granted I suppose one can question whether the manufacturer will abide by that installation procedure they list in the document, or if they'll try to wiggle out of the warranty guarantee when you file a claim.

Just wanted more insight on that.

daluu

Discussion Starter · #17 · Dec 7, 2012 (Edited)

Windows on Wash said:
Have you considered metal?

Yes, I am considering that option as well. For case of metal, what's good? Standing seam vs metal shingles?

I had interest in that a while back and consulted 2 roofers about it when they assessed my roof for a bid.

One didn't offer metal roofing. The other did and gave a bid quote that included metal options: I was quoted around $12k for highest grade asphalt shingles, $15k for metal shingles, and $27.5k for standing seem metal roof.

Not sure about the other low slope roofing options, will have to check with my local roofers, but for metal at least, I think I'll have less selection of roofers to go by. Seems in northern California, for residential roofing, asphalt shingle is most popular. I have seen homes in my area with asphalt shingles, architectural shingles, wood shake, tile, and tar & gravel. With shingles being most dominant. I don't think I've seen the other low slope roofing options or metal roofing on residential homes unless they look so much like shingle or tar & gravel. So I might have harder time finding roofers who do those roofs.

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redman88

· #18 · Dec 7, 2012

why would you hear rain more on a metal roofed house. Proper insulation and laying the metal on top of the current roof will cut out all excess noise. and in most cases the roof will last longer then shingles or torch down

AndyWRS

· #19 · Dec 7, 2012

Metal shingles also have a slope requirement, you would not typically do metal shingle on 2/12. I would go standing seam on the low slope and metal shingle on the 4/12. If you want it matching, i think your looking at SS on the whole thing. I am not aware of a low slope metal shingle.

A "metal shingle" usually refers to a certain type of metal roofing that simulates composition type materials.

A "metal shake" is a wood shake look a like.

A"metal tile" is a concrete tile look. Lower in profile to the spanish tile look.

There are also some metal roofs that simulate the clay S tile look, like Dura Loc Continental, Metro Roman, Decra Villa ect...

If you need a metal roofer your in a good location. You have access to a lot of experienced metal folks. Back in the very early 80's, metal roofing exploded in your area, it was introduced in 78 to 79 in Sacramento so i am sure they branched out to your location by 80-81. A lot of those folks are still working in your neck of the woods. At one time or another they probably all worked for Cal Pac Roofing, who was the driving force for metal back then. You had two choices then, Decra or Gerard...now you have probably more than 40 choices.

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jagans

· #20 · Dec 7, 2012

Same Thing

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