I am looking for opinions on costs & quality involved with different framing methods.
I have a set of plans that call for dimentional lumber framing throughout. The plans call for something like 20 piers. I would think that material & laborwise, it might be a better call to go with LVL’s or trusses with less pierwork underneath. I would think that in terms of settlement, you could use 1/2 as many piers with an LVL or truss system. Also, I need some opinions to how truss systems are viewed by high end homebuyers. Negatively or positively. I have been told that high end buyers would prefer conventional framing or LVL.
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Just curious - Did you buy a plan off the internet, or out of a plan book? They tend to have a ridiculous amount of posts and beams, along with stick framed roofs.
You can certainly get a lot longer clear spans with wood webbed trusses. I've designed floors with clear spans up to 32'. It makes for a real dramatic basement.
The downside to long clear span floors is that the floor system has to be a lot deeper.
When you talk about usinf LVLs for floor joists, do you really mean I-joists? LVLs are way too expensive to use in all but the most extreme cases.
Regarding perceptions - I think they vary a lot from one region to the next. Around here I don't think any particular floor system has a bad reputation.
Some more info might get you more helpful answers. Like are you building on a basement or crawlsace? Where are you located? Is this a one story or 2 story house? Building for yourself, or on contract?
To clarify, the plan was hand drawn by a local architect (Old School). It's a two story house with vaulted family & open foyer. The house had only been built one time before. The LVL's I speak of are in fact I-Joists which appear to be the standard on high end homes in this area. I have heard that trusses & I-joists do not generally fluctuate in price like dimentional lumber.
The fact that it's a 2 story house may or may not complicate things. You may be able to use less support posts in the basement or crawl space (You didn't mention which one) But you have to make sure you have support for the 2nd floor.
Wood webbed floor trusses can make it a whole lot easier running electrical and plumbing between the first and 2nd floor. But you're not likely to get HVAC ducts in there unless you have pretty deep trusses. (18" deep or more)
I'm not personally a big fan of I-joists. But they're used on roughly 80% of new homes in this area. They are stable in price and consistent in depth. But I think people tend to think they're super-strong, and overspan them.
The thread on Floor Vibration is worth a read before you choose a floor system.
I live in a two-story house.one story is "I have a headache" and the other story is "It's that time of the month."
I drew plans for a couple once and suggested trusses instead of stick built roof. Wife was against it because "those triangular things on the back of trucks look so flimsy"--then she found out how much money they'd save by using trusses and thought they were really neat. LVL's, on the other hand, even look sturdy. I've heard too that firemen don't like floor trusses or wooden I-joists because they burn through faster than sticks.
You have raised an interesting topic in the seemingly increasing use of trusses and I-joists. Some of my closest friends do double duty as both firemen and tradesmen(electricians/plumbers). The bulding system that makes it easy to run mechanicals in one trade is a potenial nightmare situation in the other.
What they have conveyed to me is that lumber has inherant strength the exceeds trusses in one respect; in a fire, a 2x10 joist system(16oc) spaning 14ft, for example, can burn up to 1/3 the way through the thickness of any number of joists and still have enough strength to hold a reasonable load(themselves). With the use of trusses(24oc typically) on the other hand, the loss of the lower cord on more than one truss could be fatal to a firefighter. This issue comes into play when they have to poke holes in roofs during a fire. What they tell me is that if there is knowledge that a building they are working on is constructed with trusses for the roof or floor systems, they just try to control the fire and forget about saving the structure because it's to dangerous.
Edited 4/27/2006 1:22 pm ET by Big Lou in Chicago
Wow; I heard firefighters didn't like them, but I didn't know they might let a structure burn if they knew it had trusses or I-joists. Hope insurance companies don't find out! (I can certainly understand how the firefighters feel.)
Where I live, the firefighters try to put out structure fires. Maybe it's a union thing.
It may be that firefighters may not know what the structure is made of, or that no cave-ins have occurred there yet because of trusses, or, like you say, they may try anyway. I think too that if firefighters knew people were still in a burning building, they would go in to rescue them regardless of the danger. But I can see not going in if you know the building is empty and you can fight the fire from the outside--especially if you know you could fall through the floor or the roof could fall in on you.
I did a post a long time ago about Trusses and Fires.
Collapses of trusses in fires *IS* an issue in some cases. But I think it gets blown WAY out of proportion.
Make good use of your toys and life will be fun. [Jim Drosdick]
I don't want to imply that they will not risk their lives if civilians are in danger in these types of structures --they most certainly will. The approach to fighting the fire and trying to save lives does make them look at things a little differant however. Also, putting the fire out is a give.
The issue that my firefighting buddies convey is that the likely hood of saving modern structures who's roof and floor systems are wooden truss/I-beam based is much much lower than those equiv. structures made with convetional lumber.
Some I joist benefits.
They come in lenghts of up to 40'. This can make for a clean, quick, and structurally sound install.
Sub floor nail patterns do not offset like they do at joist overlaps.......
Webs are easier to drill for duct runs, elec, etc......
Maybe the numvber of piers is for soil bearing values.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
A bit off topic, but why piers and not a real foundation?
You have mentioned piers - Are you referring to a pier foundation - no basement or crawlspace? If so, the number of piers may be important to carry the loads. You don't say where you are located - building practices vary greatly. I'm not a fan at all of pier foundations, but I've noticed that they are very popular in places like FL.
sorry folks, I must be miss thinking. This is a crawl space foundation with concrete block piers common to traditional framing. I am located in central North Carolina and my site has firm "clayey" soils. I will try to reduce my foundation plan to 8.5" X 11", scan it, and add it as an attachment. Thanks for all the advice.
In my area, I joist floor framing is very much the standard in both basic and custom homes. Most roofs that have vaulted ceilings are using I joists as well.Lignum est bonum.
I'm in Raleigh... Re a floor system over a crawl space you will not be able to significantly increase your spans using I-joists over dimensional lumber unless you go to significantly deeper I-joists, which will potentially burn the money you saved by installing less piers and girders.
The reason homes are often designed with a lot of piers and girders in the crawl space is because who cares if the crawl is cluttered with structural stuff and that is the cheapest way to go. Also, before making any plans to eliminate piers and girders, you need to trace the load bearing walls and any point loads down through the structure to the foundation.
For average 12' or 13' spans, WAG for price uplift for I-joists over 2x10s would 10- 15%.
You don't want to use floor trusses directly over a crawl space because trusses are difficult to insulate properly.
For a mid to upper end home on a crawl space, the norm might be I-joists first floor system and floor trusses for the 2nd floor system. The trusses are often even more expensive than I-joists but allow for a more open floor plan (longer spans) and have the added advantage of easily being able to run plumbing DWV and possibly some mechanicals especially exhaust fan ducts.
A real building supply will price out I-joists vs 2x10s for you, but if you want to start re-arranging piers and girders, you need to get the plan redrawn and stamped by an archi or PE - or at least you do here in "the city" and all the surrounding counties.
Likewise a truss company will price out a trussed floor system for you.
Thank for the input. I am in Raleigh as well. I dont really want to get into re-drawing the plans unless there would be a significant price savings in material & labor. The other concern that I had is how the typical high end buyer views truss systems. Any opinions on that?Thanks
one other thing. If I do not want to re-arange piers & girders, can I use I joists instead of dimensional lumber on the designed plans.Thanks
>> The other concern that I had is how the typical high end buyer views truss systems. Any opinions on that? << It will be fine. I'm guessing that this house is being built for you - once the house is done, and sold 5 years down the line the new buyer will never even think of what the floor system might be made of. The popular trend for houses of just about any size is open floor plans, but even more so for expensive homes and floor trusses is how you most easily and economically achieve that - the alternative being steel beams, flitch plates, etc and dimensional lumber. And, generally floor trusses will yield a stiffer floor - but of coarse any framing member can be over spanned.
>> If I do not want to re-arrange piers & girders, can I use I joists instead of dimensional lumber on the designed plans. << Yes, you can just use I-joists, but again, you get the supplier to design the floor system. IMO, most importantly you need to educate yourself as to what kind of floor performance you are looking for. For example, if you don't mind the china cabinet rattling whenever you walk by, you can span a 2x10 14' - and it is perfectly within code minimums - which is generally L/360 Live load (LL). People who can't live with what I previously described will want to go with a floor system designed for L/480 or even L/600. I'm simplifying this greatly, but to learn more about floor performance, check out Boss Hog's floor vibration thread which I think he previously referred a link to, or do a search here at BT for "L/480" or similar.
BTW - a random thought just crossed my mind.... If you think you might want one of those new front load washers, check out one of the washer spec sheets for required floor support/performance. It is quite high.
floor trusses directly over a crawl space because trusses are difficult to insulate properly
Which is part of the reason that Building Science would have you move the insulation from the floor to the foundation wall, instead. Controlling moisture from coming into contact with the floor structure being the other.Occupational hazard of my occupation not being around (sorry Bubba)