Hello out there. I have a situation where I am insulating over exposed framing and deck. I will use 2 x 4 on edge with ridgid foam in between and plywood on top. Now then, in the past I have used in that situation 3 different methods; packed in tight 3 1/2 inch foam and sealed it up, also used 3 inch foam with 1/2 inch air space but no cross ventilation and finally the air space with through ventilation. So which way is correct. Our climate is coastal northern California, not too hot, not too cool but with a lot of moisture. The roof is standing seam metal. Let me know what you think and why. Thanks T
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I am interested in this answer also, although my climate is SE. Does'nt someone have an opinion?
Instead of fitting the foam tight BETWEEN the 2x4s on edge,
run the foam solid and lay the 2x4s flat across them and use long screws to hold them down to the other under neath. then do the roof. That way you don't break the insulation package.
I have heard of that as well. Is 1 1/2 inch air space really neccasary. I would worry that the roof then would be bouncy. I like this idea though and I think the next time I have one like it I will use it. However in this particular scene the ceiling beams are all exposed and the engineer has spectd a detail that ties the sleepers to the exposed pine deck (ceiling) with A35 clips to therefore transfer the sheer ply all the way to the frameing. Thanks for the feedback -Terence
OK, so it sounds like you are also dealing with seismic design as well as roof and insulation. Let the architect have the liabilities since there is one involved.
As to slack/bounce in the steel roof, it depends on the pitch. The steel panel fabricators all have load tables available for their particular products to help you spec spans.
Generally, I have 1x4 strapping.Excellence is its own reward!
Well, kinda and kinda not. The owner is actually a landscape designer. A very good one at that, he has a formidible education in architecture but his practical application has been limited to the design of barns, folleys and other structures related to his landscapes. Basically he is an artist, he tells me what he wants and I figure out how to get there. Yes, we live on the north coast of California so guys tend to go overboard with engineering. As for me I am just 30 and this is my first "big" one on my own so I am a little nervous and don't want to make any mistakes. The structure itself is all compacted earthen material. The exterior is PISE and there are structural ramned earth columns on the inside as well as ramned partition walls. Living out in the sticks like we do there is a limit to the diversity of construction. Though with land prices at a million an acre the only new construction is large custom homes, this is (was) timber country so that is what everyone builds with and most guys don't want to change. Thats why I turned to this site thinking I could find a diverse group of builders willing to exchange ideas. Whoops, what I found was a group of rednecks comparing drill sizes and arguing about how long it took to be a "real" contractor.
I appreciate your response, piffin, to what I consider to be a boreing, but atleast relavent question. What I have decided to do (I just installed the last jack on friday- hips, valleys and dormers oh my!) is go ahead and leave a half inch air space and ventilate. It may not be absolutely neccasary but it won't hurt. I have a built out shingle molding detail so I can cleanly fur out one of the pieces to get flow from the bottom and the top will vent under the ridge. I like the idea of the continuous insulation. On my house, built in 77 with a similar sleeper detail. On our annual frost day you can see the rafter lines from outside as they melt off first thing in the morning when we get the fire cranked up.
You have my respect. Keep investigating and communicating and working hard while paying attention to the customer and you'll do well.
This forum has a bunch of good guys and advice but you do need to separate the wheat from the chaff. Lately, their's a lot of frustration with this new prospero format that is spilling over into discussions and taking up space. It's up to you how much time to invest here. I've got over thirty years building and designing and still learn here every day - but it's gotten to be more work lately.
Good luck.
bTW, I had to chuckle over your "one frost day"
I can remember one summer here in Maine that was the opposite, we only had a bout twenty nights with no frost that year. It was a tomatoeless summer - none of the fruits set. carrots and peas did OK thoughExcellence is its own reward!