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Shifty Pony posted:So basically every tract home built in the last 40 years is a write off in case of a fire? Isn't any house a write-off after a fire bigger than a wastepaper basket or a pot on a stove?
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Feb 23, 2016 05:43
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What is used for homes besides trusses? Forgive my construction ignorance but I've never seen anything besides what I think are trusses.
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Feb 23, 2016 05:44
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ohgodwhat posted:What is used for homes besides trusses? Forgive my construction ignorance but I've never seen anything besides what I think are trusses.
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Feb 23, 2016 05:50
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ohgodwhat posted:What is used for homes besides trusses? Forgive my construction ignorance but I've never seen anything besides what I think are trusses. Trusses are basically a triangle between the rafters and the ceiling joist that have been reinforced with extra members (breaking the big triangle into smaller ones). You can omit the extra members and have a triangle that's just rafter 1 -> rafter 2 -> ceiling joist -> rafter 1, but you need to use larger boards. Or you can hang the entire roof from a central ridge beam (making a vaulted ceiling), in which case you don't need joists because there's no spreading force from the roof pressing down on the walls. I seem to recall reading on these forums that vaulted ceilings are bad news in fires though. Something like, if you lose the ridge beam then the entire roof comes down all at once.
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Feb 23, 2016 05:53
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ohgodwhat posted:What is used for homes besides trusses? Forgive my construction ignorance but I've never seen anything besides what I think are trusses. Solid dimensional lumber. Trusses use smaller pieces of lumber joined together with thin steel plates. The steel softens very quickly in the heat of a house fire, which drops the load bearing capacity of the trusses to zero faster than the fire can eat through a stud grade 2x4, much less a structural grade 2x10. You have a similar problem with I-joists, where the 3/4" osb webbing burns through quickly.
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Feb 23, 2016 06:26
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Is it generally easy to identify the type of construction of a house from the outside? How do firefighters know which houses aren't worth saving?
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Feb 23, 2016 06:28
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kaschei posted:Is it generally easy to identify the type of construction of a house from the outside? How do firefighters know which houses aren't worth saving? So every dept has different rules. In mine, we will probably go onto a roof if the fire is in less than half the house and the fire has been burning for less than say ten minutes (it's up to the officer). Before we go onto the roof, the lead Firefighter will pound the poo poo out of the area near the ladder. If we think the roof is stable, we cut an inspection hole to try to determine the size and spacing of rafters and to observe smoke. Then we proceed to the target area, testing the roof stability the entire time and making smaller holes to observe smoke. We cut a louverable hole to remove smoke, make sure it is adequate, then leave the way we came. At the same time, a fire attack crew should make entry into the area and measure the point on the door frame where the heat forces the back of your hand to retreat, then it is measured again a few seconds later. Ideally, the point is at least 6 feet from the ground (with an 8 foot ceiling) and rises slightly in between measurements. A hot gas point less than around 60% of the ceiling height is grounds to stop the interior firefighting operation. Done correctly, the vent hole will lift the hot gas and smoke out of the living space to enable the fire attack crew to get to the origin and put out the fire.
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Feb 23, 2016 07:41
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kaschei posted:Is it generally easy to identify the type of construction of a house from the outside? How do firefighters know which houses aren't worth saving? I think they decide it mostly on the basis of the race of the homeowner
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Feb 23, 2016 10:04
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Can someone please post some image examples of what is good and bad in house roof construction? Also re: Tiny House Hunters--I'd be willing to bet $1000 those people were screwed financially and they bailed with the little they could get out of their mortgaged-to-gently caress house and moved to middle of nowhere under the guise of "family".
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Feb 23, 2016 15:50
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Stick framing: Long, thick rafters. May have a few structural pieces joining rafters (such as collar ties), and/or non-structural knee wall framing, but for the most part, the space under the rafters is open. Truss:  Lots of smaller pieces joined together using flat steel plates with a bunch of triangle shaped holes in them.
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Feb 23, 2016 16:08
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Shady Amish Terror posted:Holy poo poo. I love that either a family member or a social media drone (or maybe just a big fan of the show?) has started posting anonymously to the comments on that page, acting as if it is totally rational and reasonable to move six people into a one-bedroom house because you have a burning need to experience every second of your children's lives. I get it, their eldest is growing up, it's hard to let go, but I don't think this is the healthiest way of handling it. To be honest I'm kind of enamored with tiny houses, but I'm a single guy without much stuff so having that all to myself seems sort of reasonable. I can see the attraction hipsters have to container houses, check out this lady who made a "two-story" house in a 20ft container: https://www.youtube.com/watch?v=2l58L3QEVnc She had to work with a ~100sqft limit in a 160sqft (20*8) space so she built a covered porch. In most jurisdictions you get 200sqft before you need a permit, so you could do a 40ft refrigerated container (pre-insulated walls) with twice the living space and a 120sqft covered porch.
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Feb 23, 2016 16:50
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Zhentar posted:Truss: I don't see anything residential here in Florida that isn't trusses. A few much older places I've seen 2x's and relatively low sloping roofs, but pretty much all of the builder/developer level homes are trusses. My current place has exposed 3x8 cedar at the old (now enclosed) carport and laundry room, which is kind of cool only to people like me. The flat plates are called mending plates and/or gang plates. And unless you have a actual timber rafters stick vs. truss isn't that big of a difference in good/bad... it's mostly price. Here it's cheaper to ship them than make them on site.
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Feb 23, 2016 16:51
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Zhentar posted:Stick framing: I have no idea about how to build a house etc., but these pictures always scare me. When my parents moved into their newly built house about 10 years ago (not in the US), we had trouble putting holes in the livingroom ceiling while finishing the place because there are steel beams running through the solid concrete, and good luck if you hit a steel beam while drilling. It's essentially cinder block + insulation for the walls all around, with concrete/steel ceilings and a massive central wooden beam + wooden framing for the roof.
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Feb 23, 2016 16:54
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Hollow Talk posted:I have no idea about how to build a house etc., but these pictures always scare me. When my parents moved into their newly built house about 10 years ago (not in the US), we had trouble putting holes in the livingroom ceiling while finishing the place because there are steel beams running through the solid concrete, and good luck if you hit a steel beam while drilling. It's essentially cinder block + insulation for the walls all around, with concrete/steel ceilings and a massive central wooden beam + wooden framing for the roof. So...you're scared about the use of wood for building houses, period? Building out of cement and steel is overkill for your average residence.
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Feb 23, 2016 17:17
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My mom had a poured concrete basement for the house she built, and I trailed along as she talked to contractors at home shows. One of them had a client that wanted a house that was basically indestructible. His walls were poured so thick the house could be picked up by a tornado and dropped in one piece (apocryphal I'm sure).
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Feb 23, 2016 17:21
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FISHMANPET posted:My mom had a poured concrete basement for the house she built, and I trailed along as she talked to contractors at home shows. One of them had a client that wanted a house that was basically indestructible. His walls were poured so thick the house could be picked up by a tornado and dropped in one piece (apocryphal I'm sure). "Oh wow, even your checks say Pharaoh"
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Feb 23, 2016 17:24
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Is it cheaper to insure with rafters vs truss? I don't see why anyone would use rafters over truss based on cost alone assume they're not doing a vaulted ceiling. Then going back to someone saying a vaulted/cathedral style ceiling is bad for fire too--is it just because the main timbers are exposed? Also looking online at most of these vaulted/cathedral style ceilings it appears they're all placed 4' on center--assume this okay due to the additional size of the rafter pieces?
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Feb 23, 2016 17:25
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TooMuchAbstraction posted:So...you're scared about the use of wood for building houses, period? Building out of cement and steel is overkill for your average residence. I know it works perfectly well, I'm just saying it always looks flimsy in pictures and reminds me of playing Mikado. Also, I don't see very many wooden-framed houses here, ever, so "overkill" probably depends on where you are from.
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Feb 23, 2016 17:27
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I am now used to wood construction, but I grew up outside the US and wood construction was virtually unknown because lumber was very scarce. Basically any building intended to last was built out of either steel and concrete or quarried stone. Every wall in my house growing up was solid stone, 6-8" thick, and the roof was layered clay tiles over a steel base. I remember being really confused as a kid because I would watch american movies or shows and someone would get mad and punch a hole in the wall, and from my perspective it meant that person was possibly the hulk. It was very weird moving to America and realizing that almost every house was made of wood with siding and drywall nailed up over it and insulation stuffed in between.If you aren't accustomed to it as a building method it seems kind of rickety until you realize that there is really no reason your interior walls need to be solid rock.
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Feb 23, 2016 17:29
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You can make use of the space in rafter construction as a giant storage space for light yet bulky items by just putting down some plywood on top of the ceiling joists. You can even squeeze a room up there with some planning and if you accept that it will be oddly shaped and difficult to cool and heat. Trusses have too many crossmembers dividing up the space for it to be usable. There was a good /r/diy post where some idiot didn't let that stop him though and ripped out all the crossmembers to make way for his diy room filled with heavy objects.
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Feb 23, 2016 17:35
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c0ldfuse posted:Then going back to someone saying a vaulted/cathedral style ceiling is bad for fire too--is it just because the main timbers are exposed? I said that, but it was just my vague recollection of prior conversations on these forums. I could be wrong. But it makes sense to me. A truss or stick-built roof has multiple independent supports for the roof: each triangle stands on its own without requiring support from adjacent triangles or the ridge beam. The triangles in turn are supported by sections of wall, and it's unlikely that you'll lose an entire wall all at once. So the roof is redundantly supported. A vaulted ceiling has a single support for the roof in the form of the ridge beam, so if you lose that then the entire roof (or at least the entire section between the posts that support the ridge beam) has nothing holding it up. I'm unclear on why trusses are worse than traditional stick construction when it comes to fire safety. Maybe just because the boards used in truss construction are smaller and thus take less time to burn through?
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Feb 23, 2016 17:42
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It depends on your area for sure... in some areas the zoning prevents you from getting enough space in for storage/trusses. It can also be straight up goofy looking to have a roof above 5:12 in some areas because the ridge line gets so high. Not a big deal further north because of snow loads. If you're going from scratch you can get the cross members out if you talk to the truss maker. I had this on a commercial clubhouse that was essentially a huge home in construction. We had the AHU's in the ceiling and it just really meant a 2x6 bottom chord.
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Feb 23, 2016 17:50
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It seems like trusses have pulling forces acting on a lot of the steel plates, which are weakened in a fire. Stickbuilt has compressive forces acting on almost all the joints. As long as the wood can withstand the compression, you can safely replace singed beams.
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Feb 23, 2016 17:52
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TooMuchAbstraction posted:
I'm sure having all that air inside the attic also helps. I'm currently renovating a duplex that's built with trusses and it's a dream come true for running electrical wires and ducts.
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Feb 23, 2016 17:53
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xwing posted:And unless you have a actual timber rafters stick vs. truss isn't that big of a difference in good/bad... it's mostly price. Here it's cheaper to ship them than make them on site. It's not so much the cost as the spans. 30'+ spans are no big deal with roof trusses, so they let you eliminate all interior load bearing walls on your top floor. As far as fire safety goes, if I were building a house, rather than worrying about rafters vs trusses, I'd put in a fire sprinkler system. It drastically reduces the chances that the fire resistance of rafters will ever matter, and it can be cash flow positive from day 1 thanks to homeowners insurance savings.
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Feb 23, 2016 17:55
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TooMuchAbstraction posted:I'm unclear on why trusses are worse than traditional stick construction when it comes to fire safety. Maybe just because the boards used in truss construction are smaller and thus take less time to burn through? The steel plates joining the boards lose at least half their strength at typical house fire temperatures. They're thin and completely exposed, so it doesn't take them very long to warm up and soften. The components of a truss work together as a system to transfer forces from one spot to another, so the failure of a single joint can dramatically increase the forces on the other components, causing other joints or wooden members to fail as well; once one piece fails the rest will likely fail in a chain reaction.
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Feb 23, 2016 18:06
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Zhentar posted:The steel plates joining the boards lose at least half their strength at typical house fire temperatures. They're thin and completely exposed, so it doesn't take them very long to warm up and soften. The components of a truss work together as a system to transfer forces from one spot to another, so the failure of a single joint can dramatically increase the forces on the other components, causing other joints or wooden members to fail as well; once one piece fails the rest will likely fail in a chain reaction. Got it, thanks!
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Feb 23, 2016 18:27
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Zhentar posted:The steel plates joining the boards lose at least half their strength at typical house fire temperatures. Wood fuel can't melt steel plates.
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Feb 23, 2016 18:41
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You don't have to melt the steel for it to lose strength just heat it up. Think about blacksmiths, they heat steel up and then bend it or hammer it. And yes wood fuel can melt steel. Granted you would need an insulated environment and sufficient air flow but it's possible. This is how a crucible furnace works, but not likely to be replicated in a house fire.
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Feb 23, 2016 20:43
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AbsentMindedWelder posted:You don't have to melt the steel for it to lose strength just heat it up. Think about blacksmiths, they heat steel up and then bend it or hammer it. Joke flew over your head like a passenger airliner would fly over a skyscraper, under normal circumstances.
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Feb 23, 2016 20:52
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Saw this in a training course and couldn't stop laughing. 
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Feb 23, 2016 21:05
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Zhentar posted:It's not so much the cost as the spans. 30'+ spans are no big deal with roof trusses, so they let you eliminate all interior load bearing walls on your top floor. Spans and cost are directly related because the longer the span the bigger the timber would have to be and the price and size goes up sharply. You can span some wicked distances with a glulam beam but it's going to be big. And for reference to people on here 50'-60' is a general limit on wood trusses before they break them up and use girder trusses (trusses stacked, I personally haven't seen past 4-ply) because they want them to fit on a truck.
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Feb 23, 2016 21:16
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Chemmy posted:Saw this in a training course and couldn't stop laughing. Did you jump up and declaim the trainer as a shill for the Illuminati?
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Feb 23, 2016 21:21
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xwing posted:Spans and cost are directly related because the longer the span the bigger the timber would have to be and the price and size goes up sharply. You can span some wicked distances with a glulam beam but it's going to be big. And for reference to people on here 50'-60' is a general limit on wood trusses before they break them up and use girder trusses (trusses stacked, I personally haven't seen past 4-ply) because they want them to fit on a truck. That's true, but in tract housing I think most of the time they're coming from the other direction. The decision isn't 'how do I make this 30' span as cheap as I can', but rather 'I'm spending $x,000 on the ceiling/roof, with joists and rafters that gets me 16' spans and an interior load bearing wall, or with trusses that gets me 32' spans, so I'm doing the trusses'. Spending $x,000 times 3 to get the same spans with glulam was never an option under consideration.
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Feb 23, 2016 21:38
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Shady Amish Terror posted:Fun thought exercise, hilarious legal battle. The 6 people in 600 square feet were apparently serious. http://tinyhousefor6.com/ canyoneer posted:Well, it's not like they have the closet space... Anecdotal, but my coworkers tell me about another coworker who was on the show, and yes, that's exactly what happened. e: f, b on the tiny house for 6.
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Feb 24, 2016 00:28
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Darchangel posted:The 6 people in 600 square feet were apparently serious. I'm friends with a couple that are scheduled to be on Tiny House Nation. They are going to be on it because they're a young, attractive, multi-racial couple with an adorable 2-year-old daughter. Basically the perfect family to use in marketing materials. They've given plenty of reasons for why they want to move into a tiny home, but really it's because the wife is basically a hippy. They were invited to a local home show to talk about their decision to move into a tiny home, even though they were still months away from getting their home built. I ran into the wife the week after the show and asked about it. She said that their builder had some homes on display, and it was nice to finally be able to actually step into one. The lack of enthusiasm in her voice didn't surprise me at all. Basically, like almost all people that jump into any sort of trendy major lifestyle change, they didn't really think it through and fully research things before jumping feet-first into the middle of it. Given that she is currently pregnant with their second child (due 1 month after they get their tiny house), I give them < 6 months before they sell the tiny house and move back into their townhouse.
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Feb 24, 2016 02:34
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Speaking of trusses, this was spotted in Florida and indicates to fire fighters that the building has a truss roof. FIREFIGHTER SAFETY WARNING SIGNS for Structures with Light-Frame Truss Type Construction in Accordance with the Florida Administrative Code 69A-3.012 Structures with light-frame truss roofs shall be marked with the letter “R” Structures with light-frame truss floor system shall be marked with the letter “F” Structures with light-frame truss floor and roof system shall be marked with the letters “RF”
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Feb 24, 2016 04:42
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Alereon posted:Their blog actually makes it look livable after the remodel. They turned the attic into a pair of bedrooms for their older girls, remade the kitchen into a master bedroom for them, and put their younger kids in the existing bedroom. They continued the room conga line by making the dining room the kitchen, and eating in the living room. Now, mind you, I am single, but I really think I could have lived fairly happily in her digs, much less the larger idea, as long as off grid doesn't mean without internet.
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Feb 24, 2016 04:45
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"Off the grid", means "on land that belongs to my parents". Notice they never turn the camera to show the view from her front door. And nobody mentioned where her sewage goes. And the solar battery is heating the shower water? I'm kinda sceptical.
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Feb 24, 2016 05:07
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I cant think of a single house in australia that doesnt have a vaulted ceiling that ISNT truss construction? Even the old 1930's house my girlfriend used to rent was truss construction?
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Feb 24, 2016 05:15
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