Steve, what was the primary goal guiding this roof design? Modern/flat asthetics? Avoiding thermal bridging (this seems like it's along the lines of monopoly framing)? Both? Just curious.
I’m a layman, but I’ve been wondering if you could avoid having to build the rafter tails by just building the trusses conventionally. Take your sheathing and AWB to the bottom of the tail. Then install the rain screen with insect screen. Then tie your siding into a vented soffit. The soffit and rain screen would share the same air channel up to the attic. Does that make any kind of sense?
How is the attic space vented? I understand that there is air flow above the air barrier and between the roof, but you said the attic is also vented but didn’t really explain how. I’ve seen Joe talk about a SIPs roof that had moisture issues because it trapped the moisture in. They simply cut a vent at the ridge and vented both the double roof and the attic to vent.
Steve, wouldn't the layer of sheathing below the air gap be considered as your "structural roof sheathing" and therefore wouldn't you be required to have either R25 (climate zone 6) of exterior insulation on the top side of the first layer of sheathing or air impermeable insulation on the underside?
Great explanation of the details but I’m curious why you need the vent? Why can’t you do an unvented roof since you have a good air barrier between the living space and the roof?
Hah just responded to one of your comments on a different video stop following me! I just hate the idea of unvented period. Even with spray foam. Regardless the interior temp will reach the exterior temps and there will be condensation having to form somewhere. Ok so good air blocking whether siga or let’s say spray foam. Still doesn’t mean temperature isn’t transmitting through. Ok so spray foam R50 can be done like 8-10 inches let’s say. So you can save space compared to 18 inches fibreglass. But R50 is still R50 regardless and let’s heat through the same (assuming the fibreglass had a really good air barrier). So even if people like to say that spray foam connects to the sheathing so it’s all one with no air gap, then bypass the sheathing and the condensation will form under the shingles (or other roof covering etc). Recipe for bad news. Even a vented metal roof. Assuming you’ve ran underlay it would likely form under the underlay attaching the sheathing, or cause premature rusting of the screws used for the metal panels etc. I mean if I’m totally wrong I’m open to hear it, I just don’t get where people think venting is the biggest thing in an open attic, but not needed in a flat roof. I have seen so many issues in flat roof assemblies from lack of venting.
I saw something similar posted from a builder in Portland where they used a parallel cord truss in a cathedral ceiling but instead of using a sheet of OSB on top of the insulation they used commercial tyvek (I think) as an air barrier and netting for the insulation, used the flat 2x4 over the cords to secure it down and provide an air space under a plywood roof with a traditional soffit and ridge vent system. Is there any real disadvantage of not using OSB under the air gap except preventing the insulation billowing out?
Nothing new , I did details similar to this years ago with raised heel trusses . I planted a 2x2 on either side of the top chord and put 1/4" osb under them
Maybe others are just catching. I’ve not seen a roof like Steve shows, and I’ve seen a lot. Another difference, your description needs a video so people can follow it as well. Not clear what you are describing, but it doesn’t sound similar.
Any prescriptive fastening pattern for the applied eaves using the 2x4 on the flat? Every builder I talk to gets nervous about wind uplift in these applied eaves. (Not in a hurricane area or anything).
Love the detail. Any more from the job site on the netting against the bottom of the roof deck and ducting would be incredible!!
Steve may have a 150 lb frame but he also has a considerable amount of insulation and sheathing on that frame!😂✌️
150 lbs 😂
Steve “THE CAT” Baczek!!! 😂😂😂
Steve, what was the primary goal guiding this roof design? Modern/flat asthetics? Avoiding thermal bridging (this seems like it's along the lines of monopoly framing)? Both? Just curious.
I’m a layman, but I’ve been wondering if you could avoid having to build the rafter tails by just building the trusses conventionally. Take your sheathing and AWB to the bottom of the tail. Then install the rain screen with insect screen. Then tie your siding into a vented soffit. The soffit and rain screen would share the same air channel up to the attic. Does that make any kind of sense?
How is the attic space vented? I understand that there is air flow above the air barrier and between the roof, but you said the attic is also vented but didn’t really explain how. I’ve seen Joe talk about a SIPs roof that had moisture issues because it trapped the moisture in. They simply cut a vent at the ridge and vented both the double roof and the attic to vent.
Steve, wouldn't the layer of sheathing below the air gap be considered as your "structural roof sheathing" and therefore wouldn't you be required to have either R25 (climate zone 6) of exterior insulation on the top side of the first layer of sheathing or air impermeable insulation on the underside?
Great explanation of the details but I’m curious why you need the vent? Why can’t you do an unvented roof since you have a good air barrier between the living space and the roof?
Hah just responded to one of your comments on a different video stop following me!
I just hate the idea of unvented period. Even with spray foam.
Regardless the interior temp will reach the exterior temps and there will be condensation having to form somewhere.
Ok so good air blocking whether siga or let’s say spray foam. Still doesn’t mean temperature isn’t transmitting through.
Ok so spray foam R50 can be done like 8-10 inches let’s say. So you can save space compared to 18 inches fibreglass.
But R50 is still R50 regardless and let’s heat through the same (assuming the fibreglass had a really good air barrier).
So even if people like to say that spray foam connects to the sheathing so it’s all one with no air gap, then bypass the sheathing and the condensation will form under the shingles (or other roof covering etc).
Recipe for bad news. Even a vented metal roof. Assuming you’ve ran underlay it would likely form under the underlay attaching the sheathing, or cause premature rusting of the screws used for the metal panels etc.
I mean if I’m totally wrong I’m open to hear it, I just don’t get where people think venting is the biggest thing in an open attic, but not needed in a flat roof.
I have seen so many issues in flat roof assemblies from lack of venting.
I saw something similar posted from a builder in Portland where they used a parallel cord truss in a cathedral ceiling but instead of using a sheet of OSB on top of the insulation they used commercial tyvek (I think) as an air barrier and netting for the insulation, used the flat 2x4 over the cords to secure it down and provide an air space under a plywood roof with a traditional soffit and ridge vent system. Is there any real disadvantage of not using OSB under the air gap except preventing the insulation billowing out?
All these systems ceiling and roof require extra materials and work, some twice as much of both.
Did we talk about a ridge vent to allow the air a path outwards?
My guess is this is a shed roof on a modern house with no ridge.
Will that eve be safe to walk on for 50+ years?
Is plywood at the top of the wall a valid fire block?
Nothing new , I did details similar to this years ago with raised heel trusses . I planted a 2x2 on either side of the top chord and put 1/4" osb under them
Maybe others are just catching. I’ve not seen a roof like Steve shows, and I’ve seen a lot. Another difference, your description needs a video so people can follow it as well. Not clear what you are describing, but it doesn’t sound similar.
Any prescriptive fastening pattern for the applied eaves using the 2x4 on the flat? Every builder I talk to gets nervous about wind uplift in these applied eaves. (Not in a hurricane area or anything).