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-   -   Small EPDM Roof for Addition (http://www.diychatroom.com/f9/small-epdm-roof-addition-40589/)

stubits 03-18-2009 08:34 AM

Small EPDM Roof for Addition
 
1 Attachment(s)
I am in the planning stages of a small addition to my DC rowhouse. Looking at the attached picture, the addition will effectively even off the existing dog ear with the rest of the house. The house currently has a flat roof (1/4" slope) with parapet walls on both sides of the addition. The thought is to build out a parapet wall on the left side of the addition and, as with the current house, install a gutter on the edge closest to the camera. The roof is effectively 5'x10'.

I am considering a DIY fully adhered EPDM roof. There will only be one vent stack coming out of this roof. I would greatly appreciate any insight on doing this myself. I do have a couple of specific questions...

1) What material do you recommend? Particularly, are there any superior brands? Should I go with a 45, 60 or 90 mil material?

2)My thinking is to extend the roofing material up the parapet walls and under the existing roof cap. Is this sufficient? Anything else I should do?

3) I think I will handle the corners using the "pig ear" method. Is this sufficient? Is there a better way?

4) Has anyone ever purchased material from http://www.flatroofsolutions.com/? Do their prices look fair? Is it better to purchase locally?

I am sure there is plenty I am not thinking about yet. Any other suggestions, tips, concerns?

Thanks!

tinner666 03-19-2009 06:00 AM

060 or 090. I like reinforces, though it's a bear to work corners sometimes. Just take plenty of time and practice your folds dry.

7' material might fit well enough so there are no joints, except for the pipe. Use an EPDM boot.

Local supplier would be my preference. You can often get hands on type advice. Many of those guys have worked in the field. Never heard of the site you mentioned.

Black glue for pig ears, and pipe collars. Yellow glue for substrates.

stubits 03-19-2009 08:17 AM

Tinner-

Thanks so much.

I figured that 90 would be the best and given the size of the roof, the cost differential is minimal it would seem. Thanks for the recommendation on the reinforced roofing, I didn't even know it existed.

I will definitely use the EPDM pipe boot, for sure.

Do you mind a couple of other questions?

1) Do you suggest installing this over ISO board or just on top of the OSB/plywood? If just OSB/plywood, do I need to use roofing felt? For what it is worth, the attic will be well insulated.

2) My understanding is that the roofing material should run up and over the side of the parapet walls and end underneath the parapet wall cap. Is this right? Is there a particular type of parapet wall cap that you like to use? Is this relatively easy to work with? Or is there a different means of flashing this joint?

3) On the topic of parapet walls, obviously the outer wall of the parapet will be covered with siding, but the roof side, do I just cover that with whatever material I sheath the roof with (before covering it of course with the EPDM)?

5) It seems everywhere the roof transitions from a horizontal surface to a vertical surface requires a perimeter fastening strip. It can be installed either on the horizontal surface or the vertical surface, which do you recommend?

6) How do you recommend handling the gutter edge?

7) The current roof is not vented in anyway and has performed well for 75 years or so, but it is a solid brick structure with plenty of leaks I am sure. Is it necessary to vent this roof in some way? if so, what do you suggest? There really isn't a place for a soffit or any such structure?

8) Most importantly, what am I forgetting? Is there anything I really need to be thinking about that I am not?

Thanks!
4

tinner666 03-19-2009 06:33 PM

1 Attachment(s)
1) Do you suggest installing this over ISO board or just on top of the OSB/plywood? If just OSB/plywood, do I need to use roofing felt? For what it is worth, the attic will be well insulated.
I like ISO. If you go over wood, be real careful of splinters. ( No felt needed). The roller will lift splinters and stand them up. Thye can puncture the roof.
2) My understanding is that the roofing material should run up and over the side of the parapet walls and end underneath the parapet wall cap. Is this right? Is there a particular type of parapet wall cap that you like to use? Is this relatively easy to work with? Or is there a different means of flashing this joint?
Coping Metal goes here. I don't have the spec handy. Parapet Wall Cap is correct too.

3) On the topic of parapet walls, obviously the outer wall of the parapet will be covered with siding, but the roof side, do I just cover that with whatever material I sheath the roof with (before covering it of course with the EPDM)?
The roof should go under the siding. I reread the question. You're asking about the plywood or osb? Then Yes.

5) It seems everywhere the roof transitions from a horizontal surface to a vertical surface requires a perimeter fastening strip. It can be installed either on the horizontal surface or the vertical surface, which do you recommend?
Specs call for a RM strip under the EPDM on the horizonal, and a 'Term Bar' across the top of the vertical.

6) How do you recommend handling the gutter edge?
I use screw down 1x8 wood to picture frame the edges, ISO in the middle. It gives me a solid nailer for the .24 dripedge. (I run the wood about an inch past the fascia) It gives me a 'drop' at the cover strip that doesn't hold water.

7) The current roof is not vented in anyway and has performed well for 75 years or so, but it is a solid brick structure with plenty of leaks I am sure. Is it necessary to vent this roof in some way? if so, what do you suggest? There really isn't a place for a soffit or any such structure?
I don't consider myself an expert at venting in older structures, the issues don't seem 'as important', so to speak. They leak air and seem to do well. I'd advise you to check around on that, according to how you are finishing and sealing it.

8) Most importantly, what am I forgetting? Is there anything I really need to be thinking about that I am not?
On small areas, I find that I cannot just roll the roll back and start gluing. No room! I end up backrolling a foot or so, applying glue to both surfaces, waiting, then easing that bit in. Then I do another foot or so.

http://scieroofing.com/dogsear.htm

stubits 03-19-2009 07:51 PM

Tinner-

Thanks so much!

I was thinking ISO would be easier to work with... and some extra insulation can't hurt.

Thanks for the link on the dog ear. Makes much more sense now!

So, I am still struggling with the parapet wall. Can you help me through this? I see this as the area of most concern and possible water infiltration.

So, just to orient you, looking at the photo I posted earlier, I will use the existing brick parapet walls to the back and to the right. As with the existing home, the entire front edge of the roof will run off into the gutter. On the left side I will frame out a new parapet wall using 2x6s. The finished walls will be sheathed in plywood and then with Hardie Panel (vertical).

I understand the function of the coping metal/wall cap. I can get this at the roofing supply store, right? On the left, where the new wall I'll be building meets up with the existing wall, can I just overlap the wall cap from the new wall over the wall cap from the existing wall by a few inches? Or is there a better way to handle this?

Focusing on the new 2x6 framed parapet wall:

On the outer side of the wall, let's call this Side A, I assume I will just run the siding right up to the top of the wall. The coping metal will cover the seam and prevent water penetration, right?

On the inner wall (that closest to the roof) let's call this Side B, are you saying I should install siding here as well? I was under the impression that the EPDM roofing went right over the plywood wall sheathing. Am I wrong? Moving forward, I was planning to run the EPDM roofing material up and over the parapet wall (affixing it directly to the plywood) terminating it under the coping metal. Am I on point here?

Now, for the front of the wall (the 6" wide side), Side C. I was planning to run the siding material up and under the coping metal. Right? What I am worried about, however is what to do about the vertical seam created there, between the siding on Side C and roofing material on Side B.

So, am I getting this, or not at all? I was definitely confused when you said that the roofing should go under the siding. Do you have any photos of an application similar to mine? I think if I could see it, it would make sense, but I haven't been able to find a picture.

Ok, with that out of the way, couple more quick questions...

I understand the concept of framing the roof out with a 1x8, but doesn't this make the edge higher than the field? Wouldn't this cause the water to puddle? Or is the nailer actually lower than the ISO? Is this only for the purposes of the drip edge and the gutter? Or, all around? In my application would I install the 1x8 nailer all around the roof, or just on the front gutter edge?

We haven't talked about flashing. Where exactly will I need flashing?

Finally, I agree with you about the venting issue. I am not concerned about venting the existing home at all. I am just curious if you think there is a need to vent the "attic" in the addition? If so, how are flat roofs usually vented?

Thanks so much!!

tinner666 03-20-2009 05:48 AM

On the inner wall (that closest to the roof) let's call this Side B, are you saying I should install siding here as well? No.
I was under the impression that the EPDM roofing went right over the plywood wall sheathing. Am I wrong? It Does. I 'mis-spoke'.
Moving forward, I was planning to run the EPDM roofing material up and over the parapet wall (affixing it directly to the plywood) terminating it under the coping metal. Am I on point here? On the outer side of the wall, let's call this Side A, I assume I will just run the siding right up to the top of the wall. The coping metal will cover the seam and prevent water penetration, right?
Go over the top and ond down the other side to cover the sidning by 2-3? Have the cap extend down 4" on each side, and 'run a continous cleat to hold it on.
Now, for the front of the wall (the 6" wide side), Side C. I was planning to run the siding material up and under the coping metal. Right? What I am worried about, however is what to do about the vertical seam created there, between the siding on Side C and roofing material on Side B.
If I'm reading you correctly, wrap all the way around under the sidng about 6". Install term bar. Run siding to corner and close the gap where it ends. No exposed nails in EPDM.
I understand the concept of framing the roof out with a 1x8, but doesn't this make the edge higher than the field? Wouldn't this cause the water to puddle? Or is the nailer actually lower than the ISO? Is this only for the purposes of the drip edge and the gutter? Or, all around? In my application would I install the 1x8 nailer all around the roof, or just on the front gutter edge?
The ISO is 1" thick. The 1x8 is 3/4" thick. No damming issues. It will be nearly level by time the cover tape goes on. Only on the gutter edges.
I haven't detecting any flasing needs in the scenario you've described.
I haven't vented any flat roofs, though I have worked on a few that had 12" 'flue' looking vent pipe already there. I leave them there, or replace them as necessary, but I haven't spec'd any vents either.

I don't think you will have any issues, but it might be a good idea to run a continous soffit vent. It can't hurt, and you WILL be running a soffit out about 10-14" to protect the rear wall from the weather. I consider a soffit mandatory.


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