Posted: 11/13/2015 4:02:07 PM EDT
|
I'm building a second floor inside my garage. Instead of I-joists, I'm using 6"x12" solid pine beams to support the floor. I'm also using 3/4" OSB for the floor itself.
I know the spacing of traditional I-joists but I don't know what kind of spacing I can get away with using 6"x12" pine beams. Is a beam 4' center-to-center going to provide enough support or am I stretching it too far? [ETA] These are true 6"x12" sized beams and the 12" length is hung vertically. [ETA2] Corrected some terminology. |
|
What kind of pine is it, or the grade? That seems like a strange sized beam. I would think that probably 8" x 8" beams would do fine. But, check on that to be sure, don't go by my word. hahahaha I may mean well, but, I'm not a builder either. Try this: http://www.the-house-plans-guide.com/
To be safe, I would hang the joists 16" OC, for maximum strength. Since the floor space is not huge, this may only involve a couple extra boards/joists, but, they will be very strong. STRENGTH IS GOOD! 
|
|
Quoted:
The 6x12 is not the weak link, the 3/4 flooring is. It will not span 42 inches and hold up the weight of a human. BTW, what is the load on this thing? I would guess 16 inches between joists or 22 inches on center to support a human adult. Yes it will hold the weight of two humans, until the nails or screws pull out.  I used to use a 4x8 sheet of ply between two angle irons spanned in the 8' direction as a bed in my toy hauler. It will hold two humans while having sex.
|
|
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. 
|
|
Quoted:
I'm building a second floor inside my garage. Instead of I-joists, I'm using 6"x12" solid pine beams to support the floor. I'm also using 3/4" OSB for the floor itself. I know the spacing of traditional I-joists but I don't know what kind of spacing I can get away with using 6"x12" pine beams. Is a beam 4' center-to-center going to provide enough support or am I stretching it too far? [ETA] These are true 6"x12" sized beams and the 12" length is hung vertically. [ETA2] Corrected some terminology. What is the span? What is your proposed use/loading? Small things, I know, but still . . . |
|
Quoted:
All this without knowing the span or the loading. Remarkable. Quoted:
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. qft |
|
Quoted:
All this without knowing the span or the loading. Remarkable. Quoted:
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. I got a good chuckle out of it. |
|
Quoted:
qft Quoted:
Quoted:
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. qft This thread is full of industrial strength derp. |
|
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. |
|
Quoted:
You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. Quoted:
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. I'm pretty sure if you pull a structural permit, you need an engineer. But hey, what do I know...... 
|
|
D Quoted:
You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. Quoted:
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. That did very little to de-derp this thread. "Sheeting"? Really? You lost it right there. The problem is just the "sheeting", it's the entire load path. |
|
http://www.tecotested.com/techtips/pdf/tt_osbdesigncapacities
In case you don't understand engineer lingo on a 24" center with the the joist running the length of the sheet 3/4" osb will support 750 lbs/ft and it will take 305 lb/in of force to shear( completely break). Credentials: ME |
|
I am still trying to figure out if these 6X12 inch beams are running the 12 inch dimension vertically?
Or is the 6 inch dimension the vertical??? Anyway...like others have already mention a subfloor plywood that is just 3/4" thick is meant for a gap that is just 14.5". (There are some applications where 19.2" will work. Some of the newer tape measures will actually have a black diamond printed at every 19.2 ". However, I do think that layout is meant for a different type of joist.) Or 16 inches on center. The rule of thumb for joists made from regular 2X material is this: Take the span...divide by 2, then add a 1. Let's say you have a 16 foot span, dividing by 2 gives you an 8, then adding a one gives you a 9. Well, they really don't make 2X9's. So you are stuck with 2X10's, which are actually 1.5"X9.25" . |
|
Quoted:
I'm pretty sure if you pull a structural permit, you need an engineer. But hey, what do I know...... Quoted:
Quoted:
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. I'm pretty sure if you pull a structural permit, you need an engineer. But hey, what do I know...... It depends on your location. Very few locations require an engineer stamp for residential building. But hey, I have only built probably 1500 homes without an engineer stamp. and a few dozen with one. |
|
Quoted:
All this without knowing the span or the loading. Remarkable. Quoted:
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. I knew you would arrive in this thread. |
|
Quoted:
http://www.tecotested.com/techtips/pdf/tt_osbdesigncapacities In case you don't understand engineer lingo on a 24" center with the the joist running the length of the sheet 3/4" osb will support 750 lbs/ft and it will take 305 lb/in of force to shear( completely break). Credentials: ME You might want to re-check your units. |
|
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need and engineer to build a garage but this thread is clear evidence that some people do. tcpre could probably design something in just a few minutes using the existing beams and 2x4 purlins if he only had some really basic questions answered. |
|
Quoted:
Remember this thread, the next time you see me getting really pissy in an IT-related thread. Quoted:
Quoted:
This thread is full of industrial strength derp. Remember this thread, the next time you see me getting really pissy in an IT-related thread. LOL I see it regularly. I leave IT shit to the IT guys. |
|
Quoted:
You don't need and engineer to build a garage but this thread is clear evidence that some people do. tcpre could probably design something in just a few minutes using the existing beams and 2x4 purlins if he only had some really basic questions answered. Quoted:
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need and engineer to build a garage but this thread is clear evidence that some people do. tcpre could probably design something in just a few minutes using the existing beams and 2x4 purlins if he only had some really basic questions answered. They fail to see that they could easily get someone killed with their derp. |
|
Quoted:
I don't understand why you would want to waste 6"x12" beams for a garage attic floor. Does the garage not currently have a framed "ceiling" in it? He may have to span 20 feet or more (it's a garage, after all). He may be wanting to store heavy shit up there. He may not want to kill any of his kids. Serious shit, really. |
|
Quoted:
He may have to span 20 feet or more (it's a garage, after all). He may be wanting to store heavy shit up there. He may not want to kill any of his kids. Serious shit, really. Quoted:
Quoted:
I don't understand why you would want to waste 6"x12" beams for a garage attic floor. Does the garage not currently have a framed "ceiling" in it? He may have to span 20 feet or more (it's a garage, after all). He may be wanting to store heavy shit up there. He may not want to kill any of his kids. Serious shit, really. I suspect he got the beams from someone for free or had them sawed. It doesn't sound like he has had any forethought. |
|
Quoted:
I'm pretty sure if you pull a structural permit, you need an engineer. But hey, what do I know...... Quoted:
Quoted:
Quoted:
This thread reminds me why good engineers are worth their salaries.... You don't need an engineer just a builder who knows what they are doing. Everyone has said already that your sheeting is the problem. However you need to divulge what distance you intend the beams to span to know if your joist will make it and what spacing they can have. Also you need to know the grade to figure this as well. That is the opinion of a man who runs a log home construction company and uses 6" x 12" pine logs every day. A non professional would tell you that many people would good Ol boy it and probably be fine. That however is not what I am recommending. I'm pretty sure if you pull a structural permit, you need an engineer. But hey, what do I know...... Depends on the city. A few I've worked in would let you do quite a bit as long as the inspector okayed the plan. Might even give you advice if he didn't like your plan so it would pass. One of them mowed lawns for the city for 25 years. He obviously knew construction. 
|
|
I Quoted:
I suspect he got the beams from someone for free or had them sawed. It doesn't sound like he has had any forethought. Quoted:
Quoted:
Quoted:
I don't understand why you would want to waste 6"x12" beams for a garage attic floor. Does the garage not currently have a framed "ceiling" in it? He may have to span 20 feet or more (it's a garage, after all). He may be wanting to store heavy shit up there. He may not want to kill any of his kids. Serious shit, really. I suspect he got the beams from someone for free or had them sawed. It doesn't sound like he has had any forethought. The first thing we do with structures like this is define the "codes and loads". That comes before anything else. Not done here, yet GD practically has this thing detailed out. With no mention at all of columns, footings, etc. Seriously, it's not that big of a job, and it's not at all complicated, but there's no reason not to do it right. Good luck, OP, at least you're not self-building trusses. |
|
Quoted:
All this without knowing the span or the loading. Remarkable. Quoted:
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. yeah span is going to make a difference as will a bunch of heavy shit on there but 2x8s - 2x12s 16 inches on center is getting a lot closer to the ballpark than laying in some beams and spanning them with cheap ply |
|
Quoted:
I'm building a second floor inside my garage. Instead of I-joists, I'm using 6"x12" solid pine beams to support the floor. I'm also using 3/4" OSB for the floor itself. What does the existing structure look like? I assume you want to put in an attic for storage and your beams will be resting on the existing wall? |
|
Quoted:
The first thing we do with structures like this is define the "codes and loads". That comes before anything else. Not done here, yet GD practically has this thing detailed out. With no mention at all of columns, footings, etc. Seriously, it's not that big of a job, and it's not at all complicated, but there's no reason not to do it right. Good luck, OP, at least you're not self-building trusses. Pfft... some scrap sheet metal + tin snips + roofing nails + 2x4's == truss... Just make it steep enough to let water run off and not too steep to shovel the snow and you're golden. And if 4' centers wasn't the obvious choice, why would they make OSB boards that wide?
|
| 2X8 would be minimum for that span no more than 24 inches on center for a storage space, 16 inches for living space. I am running 2X6 on a 10 foot span for a storage loft that is glued and sheeted top and bottom with 1/2 inch OSB that works out good for my needs. No way I would use 2X6 on a 12 foot span. |
|
Quoted:
yeah span is going to make a difference as will a bunch of heavy shit on there but 2x8s - 2x12s 16 inches on center is getting a lot closer to the ballpark than laying in some beams and spanning them with cheap ply Quoted:
Quoted:
Quoted:
using 6x12s doesn't make any sense to me. should be 2x8s - 2x12s 16 inches on center if you used the 6x12s at 4' you would have to run 2x8s or 2x12s perpendicular to them at which point why bother with the 6x12s any more often than the length of the 2xs All this without knowing the span or the loading. Remarkable. yeah span is going to make a difference as will a bunch of heavy shit on there but 2x8s - 2x12s 16 inches on center is getting a lot closer to the ballpark than laying in some beams and spanning them with cheap ply You can't span most garages with a 2x8 even with no load. If he can it means it means he has a tiny yet much taller than average garage. I'm willing to bet that is not the case. |
|
GYy Quoted:
Pfft... some scrap sheet metal + tin snips + roofing nails + 2x4's == truss... Just make it steep enough to let water run off and not too steep to shovel the snow and you're golden. And if 4' centers wasn't the obvious choice, why would they make OSB boards that wide? Quoted:
Quoted:
The first thing we do with structures like this is define the "codes and loads". That comes before anything else. Not done here, yet GD practically has this thing detailed out. With no mention at all of columns, footings, etc. Seriously, it's not that big of a job, and it's not at all complicated, but there's no reason not to do it right. Good luck, OP, at least you're not self-building trusses. Pfft... some scrap sheet metal + tin snips + roofing nails + 2x4's == truss... Just make it steep enough to let water run off and not too steep to shovel the snow and you're golden. And if 4' centers wasn't the obvious choice, why would they make OSB boards that wide? LOL, you do make a good point. 
|
|
4' OC is way too far for 3/4 OSB.
There are online span calculators for your given subfloor, and whatever design live and dead loads you are using. You can specify a deflection, depending on your use, so it doesn't feel bouncy when you walk across it. There are also codes to deal with, don't know what applies in your area. For general storage/loft I would not exceed L/360 deflection. As a reference point, I previously owned a timber frame house built with 12x12 beams. The first floor was 24" on center, subfloor was T&G 1x6 pine with mdf subfloor. No deflection or bounce when walking around. The second floor had beams 42" on center. The floor was 2x6 T&G, and there was noticeable deflection when someone else was walking around, not bad though, as it was just a loft and two bedrooms up there. |