scottharris Posted October 28, 2023 Share Posted October 28, 2023 Hi All, I’m working on a new plan with a parapet roof. Below is my draft detail. Comments ? Or can you share your detail? Thanks! 1 Link to comment Share on other sites More sharing options...
JKEdmo Posted October 28, 2023 Share Posted October 28, 2023 1 hour ago, scottharris said: Hi All, I’m working on a new plan with a parapet roof. Below is my draft detail. Comments ? Or can you share your detail? Thanks! Scott, A couple of thoughts for your consideration... Many modern membrane roofs do not need a cant / coping wedge in my experience. Looks like you show a metal deck over a wood roof truss. Not familiar with this combo and not entirely sure if very common. I'd say either wood roof deck over wood truss or metal deck over open web steel joist. Parapet - I think bottom plate needs to go farther down to roof deck for secure attachment. Also, I'd be inclined to show a double top plate for parapet so that parapet can be "locked together" to adjacent parapet at corners. Lastly, no insulation needed in parapet stud bays. Jim 1 Link to comment Share on other sites More sharing options...
scottharris Posted October 28, 2023 Author Share Posted October 28, 2023 Thanks Jim! Link to comment Share on other sites More sharing options...
javatom Posted October 28, 2023 Share Posted October 28, 2023 It would appear that you are doubling up on the insulation. There is several inches on rigid insulation but you are showing insulation in the ceiling. Most EPDM manufacturers will call for 1/2" panels (the fiber board you are showing) or whatever their requirements show. If this is being build in CDA, you might have to show what a scupper is. If it is in the city, there is at least one inspector that will probably want to see the parapet framing be part of the wall below like a balloon framed situation. One last hint. This is sort of overkill but I have one builder that wants the edge of the fiber board to be notched down at the edge of the roof. This prevents the flashing and seams from pooling at the edge of the roof. Link to comment Share on other sites More sharing options...
JKEdmo Posted October 28, 2023 Share Posted October 28, 2023 1 hour ago, javatom said: It would appear that you are doubling up on the insulation. It could be that the upper layer is meant to be tapered to achieve drainage. If that's the case, I might call it out as such to distinguish from base layer. Jim Link to comment Share on other sites More sharing options...
Renerabbitt Posted October 28, 2023 Share Posted October 28, 2023 7 hours ago, scottharris said: Hi All, I’m working on a new plan with a parapet roof. Below is my draft detail. Comments ? Or can you share your detail? Thanks! Hey Scott, Probably put a lot more flashing details in unless youre handling this in a separate detail which I would reference. If not balooning through then would fasten the parapet wall to your decking and interrupt the insulationl Only thing holding your parapet wall is the sheething(presumably) See detail below I just drew up. Flashed cap overlaps wedge and exterior surfaces. Flash the parapet wall and lap over your exterior flashing(Under your exterior surface) as well as interior parapet flashing. Flashing at interior of parapet wall overlaps cant(if cant is necessary). Would stiffen that parapet wall up with double top plate. Like others said, no need for parapet insulation. 1 Link to comment Share on other sites More sharing options...
robdyck Posted October 28, 2023 Share Posted October 28, 2023 My comments would have been similar to Rene's; at that scale I'd try to be sure that the flashing components are highlighted. The roof assembly components could just as easily be identified with the callout for that assembly. Here are some of my illustrations; feel free to examine and pick apart what you like / dislike and then determine how you might adjust your detail. 2 Link to comment Share on other sites More sharing options...
robdyck Posted October 28, 2023 Share Posted October 28, 2023 From the standpoint of a builder, I'd also want to see how the slope is being achieved when all components appear to 'flat', but I realize that may be handled in a different drawing. I'm ok with simply noting slopes in 1/4" scale section views, but for any thing over 1/4" scale, I prefer that the slope is shown as accurately as possible. Link to comment Share on other sites More sharing options...
scottharris Posted October 28, 2023 Author Share Posted October 28, 2023 Tom, Rene, Robert - thanks for the comments! 1 Link to comment Share on other sites More sharing options...
scottharris Posted October 28, 2023 Author Share Posted October 28, 2023 1 hour ago, robdyck said: My comments would have been similar to Rene's; at that scale I'd try to be sure that the flashing components are highlighted. The roof assembly components could just as easily be identified with the callout for that assembly. Here are some of my illustrations; feel free to examine and pick apart what you like / dislike and then determine how you might adjust your detail. These are great cutaways! 1 Link to comment Share on other sites More sharing options...
mthd97 Posted October 29, 2023 Share Posted October 29, 2023 Apart from all the comments above. One of the most important considerations is sealing the roof from leaks and the actual drainage on plan view. I personally would recommend consulting an engineer in all these types of applications. In the US regulations are quite different from what we do here in Australia. I like to be extra cautious with flat roofs. Link to comment Share on other sites More sharing options...
para-CAD Posted October 29, 2023 Share Posted October 29, 2023 I had to frame this for an apartment in WA state. It's the only parapet I've done. I created shop drawings from the plans to get things correct. It was a wall set back from the edge and had a sloped hip roof around the perimeter. Not what you're doing but if it can help...here you go. Link to comment Share on other sites More sharing options...
scottharris Posted October 29, 2023 Author Share Posted October 29, 2023 3 minutes ago, para-CAD said: I had to frame this for an apartment in WA state. It's the only parapet I've done. I created shop drawings from the plans to get things correct. It was a wall set back from the edge and had a sloped hip roof around the perimeter. Not what you're doing but if it can help...here you go. Very nice, thanks for sharing! Link to comment Share on other sites More sharing options...
GeneDavis Posted October 29, 2023 Share Posted October 29, 2023 These flat-roofed projects don't have parapets but do have structural metal decking bearing on wood framing. The tower project has rigid tapered insulation, making the roof surface like a hipped roof pitched 1/4" in 12" all four ways. https://salaarc.com/project-types/featured/box-camp/ https://salaarc.com/project-types/featured/metal-lark/ Lotsa good info here about tapered roof insulation https://www.insulfoam.com/tapered-insulation/ Link to comment Share on other sites More sharing options...
scottharris Posted October 29, 2023 Author Share Posted October 29, 2023 2 hours ago, GeneDavis said: These flat-roofed projects don't have parapets but do have structural metal decking bearing on wood framing. The tower project has rigid tapered insulation, making the roof surface like a hipped roof pitched 1/4" in 12" all four ways. https://salaarc.com/project-types/featured/box-camp/ https://salaarc.com/project-types/featured/metal-lark/ Lotsa good info here about tapered roof insulation https://www.insulfoam.com/tapered-insulation/ Thanks Gene for the info! Link to comment Share on other sites More sharing options...
Gawdzira Posted October 30, 2023 Share Posted October 30, 2023 Depending on the height of the parapet, on my last project my roofer ran the membrane roofing up the vertical section and then the only metal flashing was the cap on the wall. In my case it was a pretty short parapet but from an economics standpoint, this made good sense to me. Link to comment Share on other sites More sharing options...
JKEdmo Posted October 30, 2023 Share Posted October 30, 2023 2 hours ago, Gawdzira said: on my last project my roofer ran the membrane roofing up the vertical section and then the only metal flashing was the cap on the wall. Yes, good solution and probably cheapest for short parapets. I wonder if there is a point where the roof mfg. stops warranty on product where it stops being roofing and turns into siding? Another thought for general parapet detail - I'm inclined (pun intended) to slope cap flashing inwards to drain toward interior roof. This helps avoid dirt streaks down facade from grime build-up on top of parapet. 1 Link to comment Share on other sites More sharing options...
Renerabbitt Posted October 30, 2023 Share Posted October 30, 2023 2 hours ago, Gawdzira said: Depending on the height of the parapet, on my last project my roofer ran the membrane roofing up the vertical section and then the only metal flashing was the cap on the wall. In my case it was a pretty short parapet but from an economics standpoint, this made good sense to me. I would hope they put a concave flashing.. that membrane heats and cools enough times it’ll break on a hard turn with no backing IMO Link to comment Share on other sites More sharing options...
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