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Old 01-01-2011, 05:20 PM   #16
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Hanging loft from glulam beam, pics inside.


This house may not have been designed by an architect, it may have been constructed from off the shelf plans. Further, since the contractor is not available, it is possible the house was not constructed according to the plans, assuming there were plans. The simplest way to proceed is to assume that there are no plans, and validate what was constructed by direct visual inspection.

I don't really understand the exact plan for this loft. From the diagram, it appears the OPS wants to cantilever the loft out from the existing glulam. The web site link showed an interesting loft in a garage, which appeared to be connected on one side to a beam (the article stated is was a glu lam beam), and from the photo it appeared that the other side was supported by struts connected to the ceiling. If that is in fact how it was constructed, that would make sense, since the shear on the glulam would be relatively small, and the use of vertical struts would elminate moment on the glulam due to the cantilever (the web site loft is NOT cantilevered, since it is supported on both ends).

The key to the web site loft design, so far as I can tell, is the careful selection of a suitable strut system and hanger from the ceiling. The strut needs to be adequately strong, properly attached, and the rafter where the strut is attached must be strong enough to support the load. The glulam may not be the limiting factor, since the glulam is only supporting half the loft (about 5 feet), and the loft load by code would probably be about 20 psf, for a total additional load on the glulam of about 100 pounds per foot.

So in conclusion:

A loft designed to be supported on one end by the glulam and on the other end by struts can almost certainly be designed. The design requires a check on the strength of the glulam, detailing of the connection to the glulam, design of a strut system with connections to the loft and the roof rafter(s), and design of the loft framing.

The use of vertical supports (the struts) or similar support elements on the far end of the loft is crucial, since otherwise the connection to the glulam would need to be a moment carrying connection, far more difficult to design than a shear connection, and would load the glulam in a manner almost certainly not intended by the designer/contractor.

This would be an interesting project for an engineer or architect to design. It almost certainly needs a permit, which typically means a stamped set of plans. The fact that there are apparently no usable plans available is a minor inconvenience, it means the designer will need to make measurements of all critical elements, and will need to make conservative assumptions regarding the strength of the elements.

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Old 01-01-2011, 11:52 PM   #17
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Hanging loft from glulam beam, pics inside.


Quote:
Originally Posted by Daniel Holzman View Post
This house may not have been designed by an architect, it may have been constructed from off the shelf plans. Further, since the contractor is not available, it is possible the house was not constructed according to the plans, assuming there were plans. The simplest way to proceed is to assume that there are no plans, and validate what was constructed by direct visual inspection.

I don't really understand the exact plan for this loft. From the diagram, it appears the OPS wants to cantilever the loft out from the existing glulam. The web site link showed an interesting loft in a garage, which appeared to be connected on one side to a beam (the article stated is was a glu lam beam), and from the photo it appeared that the other side was supported by struts connected to the ceiling. If that is in fact how it was constructed, that would make sense, since the shear on the glulam would be relatively small, and the use of vertical struts would elminate moment on the glulam due to the cantilever (the web site loft is NOT cantilevered, since it is supported on both ends).

The key to the web site loft design, so far as I can tell, is the careful selection of a suitable strut system and hanger from the ceiling. The strut needs to be adequately strong, properly attached, and the rafter where the strut is attached must be strong enough to support the load. The glulam may not be the limiting factor, since the glulam is only supporting half the loft (about 5 feet), and the loft load by code would probably be about 20 psf, for a total additional load on the glulam of about 100 pounds per foot.

So in conclusion:

A loft designed to be supported on one end by the glulam and on the other end by struts can almost certainly be designed. The design requires a check on the strength of the glulam, detailing of the connection to the glulam, design of a strut system with connections to the loft and the roof rafter(s), and design of the loft framing.

The use of vertical supports (the struts) or similar support elements on the far end of the loft is crucial, since otherwise the connection to the glulam would need to be a moment carrying connection, far more difficult to design than a shear connection, and would load the glulam in a manner almost certainly not intended by the designer/contractor.

This would be an interesting project for an engineer or architect to design. It almost certainly needs a permit, which typically means a stamped set of plans. The fact that there are apparently no usable plans available is a minor inconvenience, it means the designer will need to make measurements of all critical elements, and will need to make conservative assumptions regarding the strength of the elements.

Actually the back wall, and side wall of the garage is bearing walls, and exterior walls, both have footings, and the loft would be lagged to the wall studs..... The glulam would only be holding up the outer edge/corner of the loft.... So as I stated before the load on the beam is going to be "shared" if you will with the back wall and side wall.....

You know you have a point... there were 7 or 8 house designs we chose from, the name hearthstone comes to mind..... I had to pay 12k for all the modifications to this garage, i.e. the beams, and the extension to fit my crewcab etc... but never saw anything but the images of the changes to the front of the home.... I know there is plans, I saw them in the home at one time..... but I never recieved copies. Hell the upper floor was supposed to be normal cielings, and one day walked in to find everything vaulted.... Builder just said well.... now you get them free I am not going to change it... I wish that was not the case now.... but that is a whole other story all together.

I will post up images in the morning, of everything I have..... will give better input...

Last edited by wackerjr; 01-01-2011 at 11:55 PM.
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Old 01-05-2011, 01:19 AM   #18
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Hanging loft from glulam beam, pics inside.


OK As promised, had to make a few calls. And had a few things confirmed. But located some docs and finally figured out the architect. Any way long story short.... got ahold of the plans. (city does not keep plans for more than a year)
(highlighted red area where proposed loft going to go)

Hanging loft from glulam beam, pics inside.-plan.jpg
The 2 beams in the garage I poorly described in my first post are here in the images below. (spec'd on the plans)

Keep in mind the back walls where loft will attach are not in this image yet as this is in progress.

Hanging loft from glulam beam, pics inside.-untitled.jpg
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Old 01-05-2011, 05:33 PM   #19
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Hanging loft from glulam beam, pics inside.


I personally wouldn't put any more weight on it without a S.E.'s approval. The left hand post in the picture is a 6x6 (As per plans) behind the 2x4 side stud that looks to be the same width as the 2x4 brace on the left of post. All of garage framed with 2x4, no 2x6's broken down from load yet.........Appear to be 2x4's for post, but I could be wrong.....

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Old 01-05-2011, 08:16 PM   #20
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Hanging loft from glulam beam, pics inside.


Quote:
Originally Posted by wackerjr View Post
I am in the process of building a loft in my attached garage. I need more space on the floor to work, and my current shelving in the back is taking up to much precious space... so the only result is hang it up... get all the little things off the shelving and make it easy access for the wife.

You could probably use what is know as Sammi's and threaded rod to hang your loft joist from the LVL. If you can't find any Sammi's (look for a Fastenal store or online) then lag screw unistrut into the bottom of the beam. Home depot should have unistrut.

My thought process is to build a loft essentially hanging off the back and side walls of the garage and only the leading edge will need to be attached to the glulam some how...... ( now keep the whole," putting to much weight up there. You need to make sure your beam can hold the weight. Stuff to your self.... I only plan on loading the back portion of the loft, closest to the wall, so the beam is only seing minimal additional load holding up the leading edge of the loft)

You could use a ledger board and attach it to the framing members on the back wall with lag screws. Set the ledger board at an elevation where the loft joist will rest on it. Place 3 8d toe nails into the ledger board. Oh, I'd use a 2x6 minimum for the ledger and 1/2" lag screws with washers. Make sure to pre drill the holes in the framing members with a smaller diameter bit to prevent splitting them.

My question is this... I found this gentlemans Idea online
http://homerefurbers.com/projects/167

Didn't look at the link.

Mine will be VERY close to this ..... however he stated he attached his "hangers" if you will to the side of his glulam with nails and says its fine.... I don't like that Idea.... but can find no answers online about attaching to the top... and your standard "hangars" are not going to work....

So my thought is, to get some 6" channel. And use it as essentially a "saddle" if you will on the top of the beam, then attach rods from those to hold the leading edge of the loft. Thus placing the load on the top of the beam without the need to attach/drill the side..... (see images)

Unistrut would work or 3/8" steel angle lag screweed into the back side of the beam. Pre dill the 3/8" steel and use nuts and washers to attach the threaded rod to the steel.

Am I on the right track? is there a easier/better way of attaching? the internet is vauge on this (understandably so)... so any help would be appreciated.

Internet is either vague or wrong on many things. Its painful to find anything this "specialized". My ideas are from 15+ years as a home builder and Commercial GC. Good Luck.

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IMO - people are only concerned with your safety when commenting on loads/engineers etc. Its hard to answer questions when as a professional you arent onsite.

Last edited by Nucon; 01-05-2011 at 08:23 PM.
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Old 01-05-2011, 09:55 PM   #21
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Hanging loft from glulam beam, pics inside.


Didn't want to quote again... to long...

Thank you for your informative post... The problem with the internet is you don't know the "actual" persons abillities on the other side of the keyboard...

I have contacted the architect, and an engineer... but as most in this industry, nobody is in a hurry..... Neither am I but Would like some info..... you know.....

I am awaiting the S/E to call me back.

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