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Ok guys we are in the middle of a whole house remodel. Well the owners have decided they would like to add on a bedroom to the second floor in back and they want it free standing. As in no first floor. This is something that no one has ever done Around here. So I come to you guys for pointers.

The room will be 15'5" wide ad 14' long. My plan it to use 8x8 s. for the post then triple 14"lvl (what it came out to). Then tie my floor joist into the lvl then just normal framing from there on up.
 

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What does your structural guy say?

We did a master bedroom over an open carport a couple of years back. The corners were 4"x4" steel tubes with a wide flange steel section between. Wood I joists ran from that back to the main structure where they landed on a 14" double LVL. Make sure you insulate the floor well, especially if you have plumbing running through it.
 

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This sounds like it is within prescriptive means, engineering not required but prescriptive design would be.


Andy.
Andy.... I've only done very minor prescriptive design (decks mainly/headers I guess) and really am always working off plans.

Could you tell me your opinion as to any best/easiest/most understandable source for prescriptive design criteria..... maybe it's just current operative code book.... but I was hopeing for perhaps a more consise/explanatory source.

Maybe there isn't...

TIA

I wonder how many times I've called the SE... and maybe the answer was prescriptive.

Best

Peter
 

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Andy.... I've only done very minor prescriptive design (decks mainly/headers I guess) and really am always working off plans.

Could you tell me your opinion as to any best/easiest/most understandable source for prescriptive design criteria..... maybe it's just current operative code book.... but I was hopeing for perhaps a more consise/explanatory source.

Maybe there isn't...

TIA

I wonder how many times I've called the SE... and maybe the answer was prescriptive.

Best

Peter
Mostly I would use the CRC if not in a seismic D zone.

But that is Calif. Residential Code based on the 2008 IRC. I assume he is not in CA. so I think I might opt for the Wood Frame Construction Manual This Link

It is only about $80.00, but worth it if your AHJ allows it. Some jurisdictions may say that it does or does not have prescriptive framing methods in it. If they say not, then they may ask for an engineered design that could be based on the WFMC, very weird and confusing I know but most of my experience on this is in California which is a very weird and confusing place.

Andy.
 

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Mostly I would use the CRC if not in a seismic D zone.

But that is Calif. Residential Code based on the 2008 IRC. I assume he is not in CA. so I think I might opt for the Wood Frame Construction Manual This Link

It is only about $80.00, but worth it if your AHJ allows it. Some jurisdictions may say that it does or does not have prescriptive framing methods in it. If they say not, then they may ask for an engineered design that could be based on the WFMC, very weird and confusing I know but most of my experience on this is in California which is a very weird and confusing place.

Andy.
Andy.... Thank you!

Just went and downloaded the WFCM Workbook (which is free) to get a taste of their approach before springing for their Manual.... preliminarily looks like just what I was looking for and will be getting their Manual....

Sorta funny, my reference to having to call the SE on everything was in reference to your Cali code when my son and I added on 1800 to his Dana Point former cottage.

I'm Colorado (snowloads and no earthquakes) and was a newbie in Cali... never put in so much Simpson in three homes back here... should have just welded the addition together... heck I thought a 3X4 mud sill was a typo...

But I've always wanted to understand prescriptive design criteria better... not just know what goes/acceptable in my local area.

Thank Ya again....

Best

Peter
 

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Andy.... Thank you!

Just went and downloaded the WFCM Workbook (which is free) to get a taste of their approach before springing for their Manual.... preliminarily looks like just what I was looking for and will be getting their Manual....

Sorta funny, my reference to having to call the SE on everything was in reference to your Cali code when my son and I added on 1800 to his Dana Point former cottage.

I'm Colorado (snowloads and no earthquakes) and was a newbie in Cali... never put in so much Simpson in three homes back here... should have just welded the addition together... heck I thought a 3X4 mud sill was a typo...

But I've always wanted to understand prescriptive design criteria better... not just know what goes/acceptable in my local area.

Thank Ya again....

Best

Peter
When I'm in Colorado or in the east visiting family I can't help but wonder why the houses haven't fallen down yet: there is simply not enough hardware on those connections. One part engineering, one part Simpson kool-aid, no doubt.

- Bob
 

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When I'm in Colorado or in the east visiting family I can't help but wonder why the houses haven't fallen down yet: there is simply not enough hardware on those connections. One part engineering, one part Simpson kool-aid, no doubt.

- Bob
We're funny people I suppose,...at least I am....As I/we tend to assume that what we first learned is somehow standard/correct and everything else is strange.... I think you Cali's overbuild...and you think us mountain people underbuild.....;)

Not really....... but I would note that my son's original cottage (SoCal) and my daughter's (Marin) are 1949 and 1953 builds.... and 60+ years later are still standing, functional, and structurally safe.... and I haven't seen as much as one A35 in them.....:thumbup:

.... (Of course, I don't really know what Richter magnitudes they have been subjected to):eek:

(You Cali carpenters put so much steel/Simpson in a resi, I'm surprized they don't call you ironworkers...:thumbup:)


Best

Peter
 

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..... but I would note that my son's original cottage (SoCal) and my daughter's (Marin) are 1949 and 1953 builds.... and 60+ years later are still standing, functional, and structurally safe.... and I haven't seen as much as one A35 in them.....:thumbup:
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A high percentage of the serious failures come in "soft story" buildings - typically multi-unit buildings with rows of garage openings in the first floor. A big focus in California and in S.F. is on seismic retrofit of those buildings in particular. We lived in one during the quake of '89; I was home, and I could feel the building swing out over the street then come back and slam into the building next door, several times. I'd guess that the building was swinging 2 feet, on the third floor. The building didn't collapse, but after a look at the state of the piers down in the garage afterward, we moved ASAP. I've been a fan of seismic hardware ever since.
 

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A high percentage of the serious failures come in "soft story" buildings - typically multi-unit buildings with rows of garage openings in the first floor. A big focus in California and in S.F. is on seismic retrofit of those buildings in particular. We lived in one during the quake of '89; I was home, and I could feel the building swing out over the street then come back and slam into the building next door, several times. I'd guess that the building was swinging 2 feet, on the third floor. The building didn't collapse, but after a look at the state of the piers down in the garage afterward, we moved ASAP. I've been a fan of seismic hardware ever since.
Yes.... Wow I understand ....that would make me a believer too...
 

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At a certain time around here, builders would use about half the nails as we do now, trying to save money I suppose. Scary though.
 

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The OP question is not entirely clear. I've built second story additions that are self supporting, a relatively simple design project. If there is nothing at all below, The issue is sway bracing, Again nothing difficult. Essentially you are building on stilts, a common practice in some places.

It's all about understanding structure and loads.
 
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