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1/22/2020 12:12:56 PM
Posted: 9/12/2009 9:57:50 PM EST
[Last Edit: 9/12/2009 10:16:52 PM EST by Mike_Mills]
Okay, so another thread related to my sunroom addition - I need a roof.

It is a small roof (~250 sf). The joint to the existing structure will be protected by a 24" eave overhang from the existing roof. The roofing structure will be stout (3/4" plywood over 2X8 ceiling joists on 16" centers).

The roof is a shed roof with a very, very shallow pitch. It is about 1/2"/foot (I've forgotten the real number). It is almost flat. I think, for all intents and purposes, it might as well be flat. I think there is just enough pitch to ensure the water does not pool on the surface. It is too shallow to use tab shingles and most other types of roofing.

The roof will be visible from the back yard. So, I need a flat roofing product that looks good.

I have found only two types - standing seam metal roofing and spray-on foam roofing.

Spray-on Foam Roofing

Standing Seam Roofing

What do you guys think? Is there another roofing product I should consider (good looking, water-proof)?
Link Posted: 9/12/2009 10:01:17 PM EST
is there any reason you couldn't build a small, false roof? even if it was, say, 6" high in the middle (or one side) and ran down, your options open way up.

if I were choosing, I'd go with something fireproof - the metal roof. Even then, if I could, I'd throw something on top to give it some pitch.
Link Posted: 9/12/2009 10:16:29 PM EST
[Last Edit: 9/12/2009 10:18:45 PM EST by Mike_Mills]
I'm not sure what a "false roof" is.

I wanted a shed roof to ensure all the rain water goes away from the existing structure (my house). The sunroom is attached to the house and I don't want to direct water towards the building.

We do not have a wild fire hazard here, as exists in so many southern California areas. The main house has tab shingles.
Link Posted: 9/13/2009 5:00:39 AM EST
Check your local codes. You may need some type of membrane roof or the rolled asphalt.
I am assuming you dont get any snow.

A metal corrugated roof might not be so bad either.
Link Posted: 9/13/2009 7:16:34 AM EST
Make sure you check with the maker of the steel roofing on their installation instructions. I used to sell a diffrent type of panel and it wasn't recommended for structures under a 3/12 pitch due to drainage issues and causing ice dams in the winter (looking at where your at, this probably won't be a problem for you)

Everything I've seen for a low pitch or flat roof is UGLY. Normally its half lap 90# roll roofing or rubber membrane.

I think you would be better off as suggested above to put on a false roof if you want it to look good. Basically it would be like setting rafters on your existing roof deck to give is some pitch then sheating and shingling that. This option will depend on how much (if any) sidewall height you have under the eaves.


The spray foam idea is neat, never seen that before, can't really comment.
Link Posted: 9/13/2009 8:39:27 AM EST
There is no room under the eaves to create a false roof. If there were, I'd use that space to add pitch to the shed roof.

No, we never get snow here in southern California. Heck, it never rains in California, ... :-)

The standing seam metal roofing I linked to, above, is spec'd for pitches as low as 1/2" per foot, just like my roof.

I still have a little bit of leeway in the roof design. I am struggling to eek out every inch of vertical space to add a tiny bit more pitch to the roof.

I haven't identified any other roofing material options other than the two identified above. The standing seam roof comes in a lot of different materials and colors, but those represent sub-tier options for the standing seam, not a new option.

The foam roof is very attractive in terms of its performance. It is a good insulator. It is white in color, which is what I want. It is seamless, so it cannot leak unless damaged. All around, it is a good choice from a performance perspective. It is relatively new and I don't like being the guinea pig, so that's the down side.

My preference is for the standing seam material because I feel the foam roof will not look as nice. I think I would use steel, not copper. Steel has a very low coefficient of thermal expansion and won't buckle/warp when it gets hot. The steel is also available in a lot of colors. I would use white, to keep the roof cool in the summer. The underside of the roof can be insulated to prevent direct re-radiation downwards but I am concerned about the insulation raising the outer surface temperature, hence, my selecting of the white color. Copper and aluminum expand a lot more, and copper is not available in any colors.

Is there anything else I should consider?
Link Posted: 9/14/2009 11:19:05 AM EST
EPDM.

You can get a single sheet (factory seams) to cover the whole thing.

It is about as long lived as you can reasonably get.
Link Posted: 9/14/2009 2:15:34 PM EST
Originally Posted By brickeyee:
EPDM.

You can get a single sheet (factory seams) to cover the whole thing.

It is about as long lived as you can reasonably get.


This or a modified bitumen glued down rolled roofing.

Link Posted: 9/15/2009 8:56:03 AM EST
Originally Posted By Handydave:
Originally Posted By brickeyee:
EPDM.

You can get a single sheet (factory seams) to cover the whole thing.

It is about as long lived as you can reasonably get.


This or a modified bitumen glued down rolled roofing.



EPDM has a far longer life.
At least 30+ years.
Link Posted: 9/15/2009 6:05:21 PM EST
[Last Edit: 9/15/2009 6:05:55 PM EST by Mike_Mills]
Is EPDM that black, rubbery membrane material?

Is it available in white?

Mike runs off to research EPDM roofing. Google is my friend.
Link Posted: 9/15/2009 6:40:57 PM EST
[Last Edit: 9/15/2009 6:42:04 PM EST by Hueto]
1/2" slope isn't enough for a metal roof. Check your local commercial roofers and see if you can get some roll roofing. It wouldn't take more than two or three rolls of granulated cap sheet to cover the roof. Or, you could see if you could find some single ply(EPDM, PVC, TPO, etc) and cover it without seams(since they come in up to 12' and maybe 15' widths), as I'm fairly sure you don't have any heat weld tools.
Link Posted: 9/15/2009 6:45:46 PM EST
Originally Posted By Hueto:
1/2" slope isn't enough for a metal roof. Check your local commercial roofers and see if you can get some roll roofing. It wouldn't take more than two or three rolls of granulated cap sheet to cover the roof. Or, you could see if you could find some single ply(EPDM, PVC, TPO, etc) and cover it without seams(since they come in up to 12' and maybe 15' widths), as I'm fairly sure you don't have any heat weld tools.


^^This^^

Properly layed, roll roofing is about the only option. It's ugly, but it works.

Why didn't you build any pitch to the roof? Aesthetics don't count for shit when you have to use an umbrella in the house.
Link Posted: 9/15/2009 7:30:46 PM EST
[Last Edit: 9/15/2009 7:42:13 PM EST by Mike_Mills]
Originally Posted By Popo:
Why didn't you build any pitch to the roof? Aesthetics don't count for shit when you have to use an umbrella in the house.


LOL! ! ! !

The roof has to fit beneath the eaves of the existing roof on the one side and terminates above a patio door on the other side. These two features of the existing structure determine the pitch of the roof. It's that simple. I wish there was more of a pitch but there isn't.

There a LOT of flat-roofed buildings here in southern California. Mine actually has some pitch to it to ensure the water goes in the proper direction. I'm sure there is some risk of a leak but I am willing to take that chance. I think the key is to do a good job with the flashing and find a way to seal the seams (if there are any seams in the first place).

The spray-on foam roofing above touts its usefulness in flat roof applications. He sprays the flashings and penetrations (I have none) first to seal them, then he sprays the entire roof. My main hang up with this is the foam product is relatively new. It both white in color and also provides a significant insulation value (R-value) to prevent the heat from the roof from reaching the living space below.
Link Posted: 9/16/2009 5:18:23 AM EST
Spray on foam is the nastiest stuff in roofing. In a couple of years, it'll look like the surface of the moon. It blisters like crazy and is just plain messy. Foam sucks. If I find the pics of the last foam roof I walked, I'll post them. You'll gag. Who ever thought recoating a roof with spray foam was a good idea should be beat down. The only good application I've seen is using it to insulate/waterproof tents for our boys in the sandbox. And that's temporary.

If I had to roof such a small area, I'd torch down an MB Base, and torch a cap over it. Simple.
Link Posted: 9/16/2009 6:16:20 AM EST
What is MB?
Link Posted: 9/16/2009 6:57:28 AM EST
MB Base is one of Firestone's modified(ie-rubberized) base sheets. MB Base SA is the self-adhered base sheet, which has a peel away film. You stick that to the decking and torch your granulated cap shee over it. The MB base is about $100/roll and the torch cap is about $60/roll. Each roll will cover a square.

You could probably get away with some kind of panel system, but I think the standing water would play hell on it. NRCA guidlines mandate at least a 3:12 slope for standing seam if I recall correctly. I'm too lazy to get the book off the shelf. Either way, the standing seam double-lock system you linked to is not DIY unless you have the tools and access to a brake for your trim. The only panel that I know for sure that is suited to low-slope is a structural panel, which is ugly as it gets. I've seen a lot of small restaurants and such use galvanized corregated siding as roof panels for patios and canopies, and it actually looks good, if you're going for that look. It seems popular with the modern crowd.





Link Posted: 9/16/2009 11:13:30 AM EST
Originally Posted By Mike_Mills:
Is EPDM that black, rubbery membrane material?

Is it available in white?

Mike runs off to research EPDM roofing. Google is my friend.


Try 'Flat Roof Solutions'

They sell different sized sheets, but the closest one that is larger and have no seams (unless you cut them for vents).

The flat roof on my dad's finished porch is going on 35 years now, and still looks as good as new.

The only leak was fro the door jamb that goes out onto the roof.

You can cover the black with white gravel, but I seem to remember some in white becoming available.

It may not have the same life as the black though. Carbon black in the material gives it color and long term UV resistance.



Link Posted: 9/16/2009 2:23:37 PM EST
[Last Edit: 9/16/2009 2:30:07 PM EST by Any-Cal]
You might get more slope by changing whatever you are using for rafters, maybe spacing them closer so you can use narrower wood. You may be able to put supports in the span somewhere, or may be able to change the shape of the end wall. Since it is for a sunroom, you may be able to angle the end wall vertically by 10* or so to drop the span. You might be able to cut the existing eave back 1' or so and give yourself an extra few inches.

The spray on foam sucks. It works well for a little, if you can put up with the ugly. Then it stops working, any you will chase leaks down forever, or spend money sealing and painting it as maintenance.

ETA, you may be able to go 4x6 instead of 2x8, which gives you 2". Might could go 1/2 or 5/8 ply or osb, giving another 1/8-1/4". Cut the eave back to 6 or 8", which will give another 6 or more inches. You may be able to drop the fascia and run the roof of the sunroom up against the existing roof sheeting, or maybe just 1" below, which might give you some extra room. When I said change the shape of the end wall, I meant you might set the door in by a couple or 3 feet, which would let it sit where the roof was higher. If you had to do that though, the eaves would be really low and funky outside the sunroom.

What is the total length of the run down the roof to the point of support? 12'?
Link Posted: 9/16/2009 3:56:00 PM EST
[Last Edit: 9/16/2009 3:58:44 PM EST by Hueto]
EPDM comes in white also. The nice thing about the single-ply systems is that you can usually get them in wide rolls(no seems in your application) and the adhesive is pretty easy to apply. The downside is that the wide rolls are heavy and expensive. That's why I said to check out your local commercial roofer to see if he has any extras sitting around. I know we have a crapload of TPO, PVC, and EPDM laying around. To do it right, you still need to heat weld your fashing details though.
Link Posted: 9/16/2009 5:59:33 PM EST
[Last Edit: 9/16/2009 6:00:32 PM EST by Mike_Mills]
Originally Posted By Hueto:
... Either way, the standing seam double-lock system you linked to is not DIY...


I was not planning on doing the roof as a DIY. The rest of the structure, yes, including the roof sheathing but not the roofing.

Should I pay the roofers to do the sheating, too? That way it is part of their work - they can get whatever works best for them. I wouldn't want to buy and install 3/4" plywood sheathing and then have to put some sort of panel over that or rip the plywood off, or what ever.
Link Posted: 9/16/2009 6:03:35 PM EST
[Last Edit: 9/16/2009 6:05:02 PM EST by Mike_Mills]
Originally Posted By Any-Cal:
What is the total length of the run down the roof to the point of support? 12'?


Yes, a very good guess. It is about 13 feet.

Your ideas are fantastically good. I will evaluate each one. Thanks VERY much for them.

Thanks also for the tip to avoid spray-on roofing. I've gotten several recommendations to avoid it.
Link Posted: 9/16/2009 6:09:39 PM EST
Originally Posted By Hueto:
EPDM comes in white also. The nice thing about the single-ply systems is that you can usually get them in wide rolls(no seems in your application) and the adhesive is pretty easy to apply. The downside is that the wide rolls are heavy and expensive. That's why I said to check out your local commercial roofer to see if he has any extras sitting around. I know we have a crapload of TPO, PVC, and EPDM laying around. To do it right, you still need to heat weld your fashing details though.


As soon as I get closer to the roofing activity I will call some local roofers and get bids. The EPDM is starting to sound better and better. I wish I knew where I could go to look at some. I'm not too worried though.

If it is "too ugly" (as determined by my wife and daughter), is it possible to put a false, decorative roof over it (perhaps a metal roof)?
Link Posted: 9/16/2009 6:11:44 PM EST
P.S. - Guys, you are really helping me a lot. Thanks very much.

I've posted similar questions on some home improvement forums but I get almost no responses - lots of viewers but no responses. Is there a good place in addition to ARFCOM to ask about these things?
Link Posted: 9/16/2009 8:13:06 PM EST
See if you have an ABC supply, Allied bldg products, or any other Comercial roofing supply house around. THey all are going to have epdm instock that you can look at. Its going to be gray though.

It looks like a bicycle Inner tube. It can be loose laid with gravel as a ballast. Or it can be glued to ISO board that is mechanical fastened to the roof sheating.

they come in widths 10,15,20 by how ever long you want up to 100'

comes in .045 and .060 thickness.


Good luck, much like some of the info posted in this thread, not eveyone knows what they are talking about. Make sure your roofer is someone that does flat roofs often. Not some jack leg that does residential shingles and thinks he can do the epdm system.
Link Posted: 9/17/2009 4:18:32 AM EST
Coming in to this thread late - sorry bout that. As has already been mentioned, spray foam has it's uses, but roofing really isn't (or shouldn't be) one of them. It's too fragile, too easily damaged, it always has to be kept clean, and it always has to be kept protected from the elements by some kind of coating. If it's been damaged one time, it can never seem to be made right again.

If you're not doing it yourself, then a low-slope-approved standing seam roof may in fact be your best choice. metal is very durable, and if it's installed correctly the first time, it'll stay watertight until it gets physically damaged by some outside force. All other types of roofing have definite lifespans. White EPDM is a good choice, as long as you understand it's limitations. It's kind of like an innertube - if something sharp pokes a hold in it, it'll leak until that hole is patched. You should also look into white PVC and TPO roll roofing. They get installed in a similar fashion to EPDM, but all the seams get heat-welded together, and (unlike EPDM) they have a reinforcing scrim running through them. That scrim makes them less susceptible to damage from wind-borne debris. Unfortunately, they don't hold up in the sun like EPDM does. It's a trade-off - EPDM gives you longer life, but greater risk of damage. I've seen an EPDM roof that was totally destroyed by someone walking around on it with a sharp rock stuck in the tread of his sneaker. Each step made a hole, and he took a thousand steps, all over the roof...

While not as attractive as any of the other options mentioned, one of the most durable is a SBS modified rubber membrane. They're thicker, and more resistant to damage –– you can walk all over them and not hurt them. They can be adhered in hot asphalt, cold cement, they can be torch applied, or they can be self-adhesive. Normally, they're applied in several layers to give you redundant protection, and if you're fairly handy, you can install the self-adhesive kind yourself. Look into Polyglass USA, or Firestone for examples of self-adhesive SBS roofing. As a professional roofer working in Florida's High Velocity Hurricane Zone, that kind of thing is what I normally recommend. Feel free to IM me if you have any questions.
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