DIY sunroom stuck with roofing problem

rbyham · 07-26-2011, 10:43 PM

This is my first post here. Looks like a real helpful forum.

I have run into a roof design problem. I an a homeowner (versus a construction pro) with a 12x18 house addition and a 900 sq ft basement finish under my belt. So I have decent basic skills but roofs scare me.

Current project is a 7X16 second story deck with 7x10 enclosed sunroom. The roof on the sunroom is the problem. Walls are up and framed. Roof plan is a shed roof coming perpendicular off the back wall of the house. Pretty basic and straightforward except somewhere I ended up trapped between the house eave and wall height that leaves me with a roof pitch just under 2/12. Here are my questions:

1. It is my understanding that less than 2/12 cannot be shingled. I am at 6700' in Colorado Springs. Don't see a lot of snow or rain but still that shallow pitch. What would you do? Is it true no shingles if less than 2/12? If so what are my options to shingles? What would be easiest for a homeowner DIY install?

2. Depending on final roofing solution, how should I run the 2X6 ledger and flashing up under the eave?

I have tried to attach some pics to give context... TIA!

rbyham · 07-26-2011, 10:51 PM

Here are the pics (I think)

tinner666 · 07-27-2011, 05:51 AM

You'd be better off doing a gable roof. The support wall(s) are where the rafters land. A shed roof will put all the weight on the outside of the canterlever.

shazapple · 07-27-2011, 08:53 AM

I agree with Tinner. A gable would be best, or you could rotate the direction of the shed roof so the slope is the same as your main roof.

As for your original question, generally shingles aren't recommended below 4/12. If it were my job I'd go to your local hardware store and get some Modbit (modified bituminous) roofing. They come in 3ft wide rolls and you put down two layers, a nailed or screwed 'base sheet' (looks like ice and water shield), and then glue down a 'cap sheet' (same as a base sheet, but has a granular surface similar to shingles). They come in a couple of colours (black, grey, etc), but generally are 'ugly' compared to shingles.

**kwikfishron** · 07-27-2011, 09:47 AM

Why do you have that cantilevered so much? That’s a lot of weight you’re going to have hanging out there.

Let me guess….I don’t need a permit, it’s in the back yard, they’ll never see it.

Jackofall1 · 07-27-2011, 10:07 AM

Quote:

Originally Posted by kwikfishron

Why do you have that cantilevered so much? That’s a lot of weight you’re going to have hanging out there.

Let me guess….I don’t need a permit, it’s in the back yard, they’ll never see it.

I won't comment on the permit non-permit, I will agree with kwikfishron, that cantilever framing doesn't look correct, do the joist extend into the second floor? (like 2 to 1) or just face plated to the house?

If this design was not done by an architect or engineer then I think you should at a minimum have the designed checked, ie the amount of cantilever and the footings for the columns.

Mark

rbyham · 07-27-2011, 11:08 AM

Thanks for all the help and input folks. As to the permit issue trust me it is permitted and all plans approved. This includes the cantilever. Yeah it looks long in the picture but measures out to just under 24" ...well with code here. I have already had the framing inspection for the deck on down and it was passed with no questions. As to attachment I used standard 2x8 hangers attached to 2X10 ledger double lagged every 16"oc to house band. On the outside of the cantilever the hangers go upside down to counter forces. Also plan called for double 2x4s between the two 4x5 windows but I tripled it when I built just to make sure. I considered gable roof after getting the deck built but that plan change required all kinds of reworking and even an additional post down under in order for weight transfer to outside walls. So I am going with original planned and approved shed roof.

Anyway... I found this product last night and got it approved by my inspector today - http://www.solutions.mfmbp.com/MFM-0...20brochure.pdf I just have to make sure to adhere in application to Class A fire rating. I guess that means my OSB substrate plan ain't gonna work. Can anyone comment on the product itself and tell me what constitutes a "non-combustible substrate" for the roof?

Thanks for all the help...

Rick

rbyham · 08-07-2011, 11:37 PM

I did go ahead with framing for shed roof. I will try to post pics tomorrow. I went with peel and stick rolled roofing two layer system. Over the OSB I first ran drip edge on lowest edge of roof. Then I ran my peel and stick base layer. That went pretty well though I lost one length when wind blew it back on itself and it all stuck together. Once that stuff is stuck it is stuck. But I had plenty of base. After base down I ran drip edge nailed in 1/4" bead stop leak flashing cement. Then I laid my cap layer of roofing. Again went well. Basically for the DIYer like me you just have to take your time.

As I got ready to run cap layer, I realized I forgot asphalt primer which evidently should have gone down on drip edge to make sure cap layer adhered well to drip edge. But it being Saturday afternoon no roofing supply places open here. But I had to go for it cuz rain clouds were moving in. SO I cleaned drip edge best I could and laid cap on. It seems to be sticking well around all sides. My question is, if the edges start to look like they might be peeling from drip edge what recourse do I have to seal that edge? Is there a contact cement that would do it? Or do I go for pulling cap back off drip edge, hitting it with asphalt primer and trying to reseal? What do you think?

Thanks in advance!

rbyham · 08-07-2011, 11:39 PM

Forgot to add that between the OSB and base I had to lay 1/4" dens deck for fire rating. I put down the primed dens deck so base adhered nicely...

shazapple · 08-08-2011, 10:19 AM

Mastic, or some sort of sealant. Worst come to worst you could cut the unadhered cap sheet off, put down your primer and then put a new strip of cap around the perimeter.

rbyham · 08-08-2011, 05:40 PM

I don't think I have worked much with mastic. Is that a adhesive or more just a sealer? Any idea if HD carries this and if there is a brand name?

rbyham · 08-08-2011, 06:06 PM

sorry... i did some looking on my own... looks like handy adhesive

robertcdf · 08-09-2011, 03:17 PM

Wow... A shed roof is going to be adding a lot of extra weight to that outside rim. Just because something does calc out as working on paper does not mean it should really built that way. Not trying to be mean but I would reconsider the build, a gable roof would have been better from the start both in appearance and functionality.

The only thing the inverted hangers are doing is keeping the rim from dropping, they are not really doing anything structural.