# Structural Engineer in the House???



## Firewalker (Jan 3, 2011)

If you are getting tired of the questions just tell me. It's cold outside and snowing and I am just surfing and pondering all of lifes mysteries.

I am planning on having a bar/mancave area in the shop and it will be lofted on the top for massive storage. Imagine not climbing into the attic to get Christmas decorations.....Halloween......Thanksgiving etc. It's not that I don't like crawling on 2x lumber and sticking the back of my head with roofing nails.:laughing:

Anyway, the space that will be decked will span 20'. There will be no support below with exception of the studded walls. (2x4) construction. It will be a 20' x 16' loft. I can use whatever material it calls for but I would like to do it with the least expensive method that I can install myself. IE: 8" steel I beams and forklift won't happen. I can do 2x8s laminated with plywood or ???

In my old shop I had a 16x12 loft that was supported on 2 3/8 oilfield tubing with 1/8 flat strap on 2' centers. It was decked with 3/4" CDX and had some vertical pipe supports to the main ridge beam.

I know this is a ww forum but I have found myself surrounded by a lot of people who have done a lot of things in life. I wouldn't be surprised if this was one of them.

Thanks for any words of advise you might offer.

Be safe! Stay warm! 

Scott


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## Greg in Maryland (Jan 6, 2011)

Scott,

First, I am not a structural engineer, nor do I play one on TV. However, I did stay at a holiday inn last night ......

With that said, I recall watching a basement renovation show on tv where they removed the center column and replaced it by laminating the beam with iron plate bolted to the beam. I would think that plywood lamination would not be sufficient.

Good luck with the build.

Greg


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## Firewalker (Jan 3, 2011)

Thanks for the reply. To make this a little more clear. These are for the support rafters that will have both a ceiling attached below and a deck on top. I am not sure of the spacing. I was thinking 24"

I wonder if you attached some heavy angle iron to the lumber if that would work?

Forgive the craptastic drawing...here's what I am talking about.


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## woodnthings (Jan 24, 2009)

*20 feet is a loooong span*

Not quite clear on this:
Anyway, the space that will be decked will span 20'. There will be *no support *below with* exception *of the studded walls. (2x4) construction. It will be a 20' x 16' loft.

OK pick one. Free span or supported? Supported on either end?
One support in the middle would greatly simplfy your issue, but let's go for broke. If it's a platform 20 x 16, supported on 3 sides, open on one end, you can run 2 x 10's on the 16 ft length no problem, but then you'll need to support the free end somehow. You will need an engineered micro lam beam or steel to support all that weight. Even the deck itself will weigh plenty.
I've put about 5 - 8" x 10" x 22 - 27 ft beams in my house.
5 of them by hand with several guys, a come along or 2 and one big one, 1200lbs. with a tractor with forks. It can be done inside, without a forklift, 2 of mine,20 ft long, 666 lbs each, were on the second floor, came up outside on an oak tree and in a window, but I was younger then. :laughing:
The floor deck must rest on hangers or on top of the beam so that reduces the ceiling height at that location. This was all 
Michigan Engineered SOP (seat of pants). The steel supplier was helpful in determining width and depth of the beams.  bill


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## Firewalker (Jan 3, 2011)

It will be supported on 3 sides by the walls. If it has to have any support in the middle I can weld some pipe up to the roof trusses however I would like to avoid this unless needed.

Lemme see if I have a pic I can post of the area so far.


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## woodnthings (Jan 24, 2009)

*Another approach*

http://www.internationalbeams.com/i-joists/
Run some "I" structural joists, rather than 2 bys, across the 20 ft dimension so that each joist becomes a load bearing member rather than supporting the short dimension on a beam.
That makes way more sense. JMO  bill


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## cabinetman (Jul 5, 2007)

Firewalker said:


> I know this is a ww forum but I have found myself surrounded by a lot of people who have done a lot of things in life. I wouldn't be surprised if this was one of them.
> 
> Thanks for any words of advise you might offer.
> 
> Scott



You are right, this is a WW forum. If there are any structural engineers as members, they might chime in. Suggestions on a subject like this are a lot like electrical suggestions. When projects can possible be life threatening a licensed experienced structural engineer, or an appropriate engineer should be consulted.

I, like many on the forum have done a lot of things in life, but I wouldn't offer suggestions. Rather I would urge getting professional help.












 







.


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## jstange2 (Dec 5, 2010)

Here is a table that shows spans of certain floor I'beams. Consult your local lumber yard and tell them how much you plan on storing up there and they will get you set from there. Local lumber yards are better than big box in this situation sometimes.
"*Wood* *I Beam*™ Joists - Residential Floor


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## maxwoodshop (Feb 7, 2011)

hey buddy i to am not a engenier but i have been framing for 8 years i would run a couple microlambs (lvls) along the 20' span 12"ers or maybe even 14"ers. but the other guy is right u should go to a local suppler and they will be able to tell you the right size and nailing and or bolting pattern to laminate the beams together. you should also use hanges for the joists or a ledger strip. and futher more the 2 by 10s mentioned above will be the correct size to span the 16 foot way of your loft, unless your planning to have a big party up there or store semi truck engenies and so on. any way good luck


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## Firewalker (Jan 3, 2011)

Thanks for the replies. I will make some calls and see what it calls for. I can appreciate that one wouldn't want to give information on a subject without being 100% certain what they are saying is true. If someone here is a homebuilder and they know from either the architect or the inspector that this span requires this material or it won't pass inspection...that is what I am looking for. I wouldn't want someone to provide a half baked response on what could work, maybe. I also don't want someone to think they are taking on my life as a responsibility by giving suggestions on a web forum. In my career there are some things that are my opinion.... "is my hand broken?" "I am not a doctor ma'am, so I can not say" there are some things that are fact. "Is 0.9% saline isotonic in humans?" "Yes it is." As I have said before I tend to overbuild things because I am not sure of the minimum but I feel pretty sure it won't break because of how I built something. (usually overdone) I certainly hope this thread didn't make anyone uncomfortable in responding. Thanks again for the replies.

Here is a pic of the area in question. I do realize the uncovered wall was leaning when the pic was taken. It was lacking the top cap and out of square.


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## Oldtimecarpenter (Feb 7, 2011)

For that length of span you will need a structural LVL type of beam or joists. Rather expensive for sure! Otherwise it will need to be supported with concrete lally columns as most building codes require. You possibly may get away using a 4x4 post placed at about 8 foot centers depending on the weight load it will carry even using the 2"x8" joists at 16" centers. I'd be sure to add some diagonal bracing if it is free standing on two or three sides. I'd also check with the local building department if a permit is required. Should something happen your home insurance may not cover that if built not complying with building standards. Good luck!


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## BWSmith (Aug 24, 2010)

Just a bunch of guesses....

Is there a footer under that 2x4 wall?If no,then you're gonna have a hard time 'splain'n how its holding up a beam.Likewise,putting columns on a slab just anyole'where.Further,is this slab on grade or is it on fill?One thing most have a hard time understanding is that slab on fill is treated like a suspended slab,WRT steel and engineering.At least how its been explained to me.....it don't matter how well soil/gravel's been compacted,we still treat it like a suspension.

Theres ways of fixing above,but it gets a little too drawn out.........and more than likely explains why a "real" engineer gets a little hinky even discussing such.And in no way am busting on the whole thing,just trying to help.BW


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## Firewalker (Jan 3, 2011)

BW you bring up some good points I hadn't thought of. The wall is not on a footing and it is on compacted fill. It's a 4 inch slab of I believe 3000 psi concrete with fiber. It may be better to attach the loft to the 7 inch steel pipe that is in the ground well below the concrete. The posts were placed when the barn was built and it had a dirt floor that was leveled before the slab was poured.

It's a head scratcher for sure. Thx for the input.


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## BWSmith (Aug 24, 2010)

Check your PM's,BW


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## woodnthings (Jan 24, 2009)

*Here's a "thought"*

BW makes some good points on supporting the slab.
Your support wall coming into the room will become a load bearing wall, if you run some "I" joists on the 20 ft length, with a distributed load. Unlike if you run the floor on the 16 ft length and use a beam for the open end. Depending on the total load, the distributed load is easier to manage along the length of the wall, double plates, header etc. If you concentrate the load on a post under the beam, you should saw out a 24" sq in the crete and put a 12" thick footer in after digging down to virgin/compacted soil. The footer will support the load on the post. You won't lose any head room if you use joist hangers. All this free advice is subject to local building codes of course, this is just the "planning" stage for discussion.....
I had to saw the crete and put a footer under the far end of my 1200 lb, 27 ft Steel beam. I probably used a 30" square and filled that sucker full. I also used a triple laminated PT post, 6" x 10" under the beam and used plywood to face the studs for additional rigidity. Building is as much fun as woodworking.....sometimes. unless it involves concrete. :no: bill


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## frankp (Oct 29, 2007)

I won't guarantee anything, but my wife is a structural engineer and I'll try to get her to look at this for you. My guess is she'll say go with a lam or steel support beam somewhere in there, but I'll see what she says.


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## Oldtimecarpenter (Feb 7, 2011)

Most all of these are solid advise. You certainly can draw up a set of plans utilizing the input from this forum, then present it to the local building inspector. In turn, he / she will approve those plans but may request additional items regarding the state and local building code. Specify and accurately draw the complete plan with all the items including all materials used. Best to draw it to scale as best as possible. I'm sure they will be glad to help since you are the homeowner and not a contractor. Again, good luck!


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## frankp (Oct 29, 2007)

Okay, discussions with the wife say "storage is storage... we design for 125 psf (pounds/square foot) per code" IE with the "non-load" wall and two outside walls forming a loft with three supported sides, she thinks it's doable. "The third wall will become a load bearing wall over the 4" slab on grade BUT you SHOULD add a footer or "thickened slab" (12" thick) below that wall if you want it to be done properly. Then use laminated beams/joists to get the 20 foot span." (Her spreadsheets for calculating these things say 2x12 at 12" on center won't support the load across that large a span. She says an LVL (1.9E grade) 1 3/4 by 15 should work on 16 inch centers.) 

That's what the structural engineer wife says. She also says, get a professional engineer in your area to check the design, just to be sure. (Actually that's my addition to cover our butts  ) So, start with our suggestions and get it checked by a building inspector/structural engineer familiar with code issues in your locale, and you should be good.


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## Firewalker (Jan 3, 2011)

Frank, thanks for the reply and please relay my thanks to your wife as well. Very cool of both of you indeed. This portion of the shop is not a must do right now so I will have time to do whatever it is to make it right. Will post up what I come up with. Thanks again.

Scott


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