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Tahoe went from building 19 pitch steel roofs to a lesser pitch because the snow slid off and turned the house into a cave. Now going to a whatever you're calling flat, 1-5 pitch is batshit crazy imo. They have to overbuild the frame to hold the load too. There's no good answer for Tahoe.
Every roof style can leak, including metal...and is loud af in the rain.
Flat roofs are totally do-able in any climate with modern materials. TPO is pretty amazing stuff, and even better than EPDM.
My house was built in '79 by hippies, and had a flat roof. At some point later a pitched roof was added atop it, presumably because they couldn't keep the thing from leaking. But now, with modern materials & methods, flat is no problem.
As a side note, roofs are engineered to support whatever snow load is expected. 130#/sqft near Tahoe, for example. The pitch doesn't affect it, even when a metal roof will be installed and snow will self-shed. I argued with an engineer a bit about this once, but obviously that went nowhere.
Same with our cabin in the old Alpine Meadows. It had a flat roof, the snow stacked up there like crazy and it never leaked. It was a really small footprint 2 1/2 story high, but nonetheless, I love the design. I have a bigger house now, but it has a slanted tin roof that sheds, and sometimes it doesn’t shed completely, and it’s a big pain in the ass. You can see some water damage in the areas over the deck where for assorted reasons it didn’t shed, and then you have the H2O back up.
I've got a 0.5/12 flat standing seam roof in snow country that has been holding together well. I can't recall the specific brand but know that we paid a good bit extra for a standing seam that has a mastic adhesive in the female side of the standing seam. After we installed the roofing we then went back through with a plug in electric crimper that we ran down and back on each junction.
We are 8 years in and it's holding together well with no ice dam issues but man will I be bummed if I have to install another one!
Our roof is rated to ~100 psf and we've got snow brakes to keep it all up there.
tl:dr My 8 year old flat roof is working so far. Here is to 92 more years.
A double crimp standing seam isn't letting any water in and would slowly shed even on a 1/12 pitch. If it was tar before nothing shed off it so built to hold the load. Carport so no need for a cold roof.
DO NOT buy any "click lock" standing seam for this pitch as it will likely leak.
The Socal style houses I see being built around here are being being built with steel beamsQuote:
Originally Posted by jackstraw
Our roof has varying pitches but the steepest is comfortable for my wife to walk on and the flattest is comfortable for me (climbing a ladder to get up there is another story.). We have had leakage in the past with ice dams with water coming through around a poorly sealed vent stack. Since reroofing (architectural comp) with a membrane we've had no leaks. Adding more ceiling/underside of the roof deck insulation has helped a lot with the ice dams.Quote:
Originally Posted by climberevan
Our ground snow load is 315 psf.
a 15:12 roof doesn't need to carry the same snow load as a 5:12
That's good news! Hopefully you get a 30+ out of it. New tech has helped a lot, but I do feel like proper installation is critical as well. It's not rocket science, but many roofers are batshit crazy...and have been known to have a drink or ten at lunch [emoji16]Quote:
Originally Posted by John_B
The snow load is the snow load. It's a function of the geography and the climate, not the structure. The engineering to handle that snow load obviously depends on the slope. At least that's my amateur understanding. And as I learned when the engineer for an addition we did used 200 psf instead of 315. Back to the drawing board. Literally.Quote:
Originally Posted by ::: :::
Some jurisdictions allow for a lower load requirement if the roof has a shedding design.
Sent from my iPhone using TGR Forums
ground snow load is fixed for any given spot (determined by specific elevation & local climate usually), but that isn't necessarily the final factor as applied in the roof design load calcQuote:
Originally Posted by old goat
I've built houses in eight different states back when I was skiing and Truckee was by far the most strict with their building codes due to snow load and earthquakes. The one that baffled me the most was the amount of nails on the sheathing. Inspector sat and watched us shoot more nails at this house in OV. I was laughing thinking the studs are going to be blown to smithsrines. I don't recall exactly, but it was like every 4" or something. We'd typically do every 6-8-10" or so...idk. You just walk down the wall firing nails...plywood is not going anywhere.
Quote:
Originally Posted by ::: :::
I am sifting through the best option for insulating a basement sill plate on a complicated footprint with exposed ledge, a history of water intrusion, humid summers, and cold winters. Closed cell spray foam two feet below and two feet above would be so easy but I really want figure out another way.Quote:
Originally Posted by ::: :::
Nerd alert:Quote:
Originally Posted by jackstraw
Plywood resists lateral loads (wind or seismic) by securing the sheathing panels to the studs with nails to create a shear wall. The tighter the nailing, the stronger and stiffer the wall. Truckee is in Seismic Zone D (high), so that most likely explains why your shear walls needed more nails, compared to other states, than you are used to. The spacing of base plate nailing (or bolting to the concrete foundation) also needs to be reduced.
Snow loading is interesting. The ground snow load is the same for any type of structure and is based on location. Truckee has loading from 130psf up to 500psf depending on location and elevation. They based all their "psf" loading on a study document from 1973. Code mandates that the ground snow load be converted into a roof snow load, and then a sloped roof snow load. These equations reduce the ground snow load based on roof temp, slope of roof, snow stops, etc. The steeper the roof, the lower the sloped roof snow load will be. Code also makes engineers check for drifting and sliding snow (such as a high roof shredding snow to a lower roof, or areas where wind would blow snow up against a wall).
We engineers can design flat roofs in high snow load areas, but no one ever likes how large the roof rafters become.
water intrusion element needs to be solved independently of the insulation firstQuote:
Originally Posted by Mazderati
spray foam can be pretty good at the plate/rim
whether it goes beyond that is a bit of a specific issue to your particular situation that might be best answered by a local pro
Attachment 505725Quote:
Originally Posted by climberevan
It's older construction and half ledge so there is only so much to do for water. Even if the exterior perimeter of the foundation is waterproofed and insulated, water will still run right into the foundation wall. Going to try and connect with a local trade school for a quality referral. Retrofitting without compromises is difficult.
Twelve years old but the best video I've found on the subject of insulating and managing moisture in basements.
https://www.youtube.com/watch?v=kwn0Vjw_ji0&t=3s
your moisture & vapor control layer may need to be run immediately underneath the floor framingQuote:
Originally Posted by Mazderati
& leave the crawl to be damp
this is for flooding, but seems similar to a porous foundation wall
https://basc.pnnl.gov/sites/default/...al_BSC_3-2.jpg
Nice. There was no doubt in my mind that an engineer had calculated the nail spacing needed, but us East coasters were blown away by it.Quote:
Originally Posted by SorryBro
I can't remember if it was Tahoe, but somewhere had us sheath vertically vs horizontally. I have no idea what the difference actually is, but primarily the houses I worked on were horizontal. I didn't frame much, I was mostly a finish carpenter.
That seems unwise, given that someone might reroof with comp without getting a permit, or the building dept doesn't bother to check that the house was built to shed. (But not in Truckee, where the building dept put a deed restriction on our house as a condition of permitting and addition that could shed on the neighbor.)Quote:
Originally Posted by nickwm21
I think that was what I was trying to say about snow load, but I used the words wrong.Quote:
Originally Posted by SorryBro
An architect friend who visited us--the first words out of his mouth were "you have no shear wall" (Glass apparently doesn't resist lateral forces very well, particularly when it's hardly attached to anything.)
Our rafters are 4x12 on 24in (I think) centers. The house is basically post and beam with massive timbers salvaged from a pier in SF Bay. I suppose it would resist racking pretty well if those rafters had solid connections to the beams, but they don't, just toe nailed. I have earthquake insurance.
Solid advice everybody on my roofing issue. I think I'm just going to go with the GAF self-adhering rolls. it looks like a way better system than the non-adhesive rolls I've got up there now just secured with some roofing tar, there are at least 2 layers in there and its just an open carport and unfinished garage roof, so not highly important, just don't want it to leak.
I'm headed up there tomorrow with some roofing tar and try to seal any tears or open seams I can find and then in the spring when it warms up I'll just put all new sheathing and do the full GAF flat roof system (asphalt primer, underlay, cap sheet) so i can also redo my soffits, gutter, and attachment to the house at the same time.
In Vangroovy all the condo's were finished in big orange tarps becuz the tarps were keeping the rain out while they they fixed brand new condo's with water issues
And I'm not talking about a few buildings I'm talking about the whole fucking city, either from water ingress due to poor roof design or poor insulation technique
IMO from growing up in the north wet you want a roof with a bunch of overhang but what happened is they went all fucking post-modern-california in a big part BECUZ the bylaws were changed so you could have a bigger condo by not having an overhanging roof which was perfect for the condo buyer until is all leaked
but you probably already read it all in my link eh
So update on the home ceiling speaker thing. I bought an Arylic A30+ on a black Friday sale for $95. The thing’s tiny so I’m gonna hide it somewhere. Pretty fucking amazing. Easy, super clean app too.
https://uploads.tapatalk-cdn.com/202...484724700a.jpg
https://uploads.tapatalk-cdn.com/202...1707227514.png
Thanks for all the suggestions and ideas.
Starting to think more about a home addition. Considering having it done w/o a permit but requesting that it be built to code. We will need to get a HELOC or similar to finance.
Question: will we be able to insure the addition and will we be able to have a claim on the addition if something happens to it?
How the fuck do you do that without a permit? Not sure about your local regs but I'm in unincorporated county and my neighbor got fucked trying to just build a garage w/o a permit. Had to tear it down, chop up the cement and start from scratch. He got screwed.Quote:
Originally Posted by bodywhomper