How to clear span 23 ft?

[Hades12]

We have moved into a new shop and I want to setup an office in the back as a second floor. My thought is to build it like a deck. One beam across the 23 ft and use 2x6 for the 10ft from the block wall to the beam. We will be parking cars under it.

I am not sure how large the beam would need to be to span that far. A post in the middle would drop us from 3 cars across to 2. The upstairs will have a couch and tv plus a few computers and desk.

 

[SGKent]

you need to visit a structural engineer. The loads have to be calculated for what will be in that room as well as the strength of the wall and foundation.

 

[Dan in Pasadena]

Yup, what he said. You're likely gonna use a wide flange beam, i.e. an "I beam" or a fairly deep sectioned glulam.

 

[kwb]

Loft is 23x10 if I read this right- glulam is probably going to be ~16" deep (assuming 5.5 wide to put a wall on top of).
Lumber yard will size this for you usually for something this straight forward.

Edit - go with 12 deep and not need to rip your subfloor sheets.

 

[Red05GT]

The additional 2 foot of depth will increase the weight of floor deck and load and
required an even larger beam to clear span. Could possibly bury the beam partially in
a knee wall which would serve as part of a railing/wall.

 

[Hades12]

10ft is the max. that is where I get to a Roof support post and any past it and we will not be able to move cars between it and the next one.

There will not be a wall on top of it. just a railing to keep the kids from falling off, that is why I say more like a deck. No real floor either just OSB or a cheep plywood.


It will be in the back to the left from the back beam to the back wall and to the wall on the left over the cars.

 

[Hades12]

Here is the other side of the shop

 

[Hades12]

http://www.aitc-glulam.org/pdf/Capacity/SP_49.PDF

What is the C of D is that the load?

 

[GeorgiaHybrid]

You have other major issues.....I don't think that lift has the capacity for the 4 wheel vehicle between the posts.....

As for the other question, a lumber yard should be able to size an LVL as long as the load you place on the floor is not too large. If you go over their limit, a wide flange beam might be required but you will need an engineer to size it.

 

[John in OH]

Just an off-the-wall thought ..... perhaps you could partially support the new horizontal floor beam by suspending it via cable or threaded rod from the overhead roof support beam that appears to be directly over where you will want the front edge of your deck.

 

[aubrey601]

Edit

 

[theoldwizard1]

GluLam/LVL is the answer.

How are you going to attach it to the I-beam post and to the concrete/block wall ?

You might have to upsize the floor rafters to 2x8, but you could cantilever them out 2' past the beam giving you a 12' floor.

 

[deuces2]

I didnt clearspan, but I did add 240 sq ft with my mezzanine,I used treated 4x6s and 2x6 floor joist with hangers on the outsides and 2x8 joist in the center with hangers fairly cheap and done it all by my self.I did not use any of the buildings structure for support .I just built a free standing deck,fairly cheap

 

[OccupantRJ]

You could use 2 posts instead of clearspan, then you would have 3 bays to park cars in. Also would no longer need a huge beam.

 

[fury9]

I would use another I-beam structurally attached to the said I-beam you want to start with,and cut a pocket in the wall to set the other end on/in then you will attach the appropriate 2x to the top of the beam and away you go.you will need to do this in the back wall and side wall I'm no substitute for an engineer though but that's probably what they will tell you to do. They just have the know how to calculate live load and other said equations. It appears as though you have some type of small overhang on the back wall?bout 8' up?If you did want to go with wood thoug you're gonna need some typw of engineered floor joist to span 23'. I have sen many LVL sag in the middle even after tripling them up. I would prefer a big hefty glu-lam over a lvl and a engineered floor truss first

 

[Iowa Mark]

How about building a plywood skinned "box beam" that acts as the structural support and as the railing for the kids. A four foot high stick built wall with a nailing strip on the lower section for joist hangers and skinned with 3/4" plywood on both sides will hold almost anything you want to put up there. I've built them to span double garage door openings, hold up the roof joists, add insulation against the weather and hide wiring for years. Best part is they don't require a crane to put them in place.

 

[Hades12]

That might work good, I have no clue how to spec it out. If I am reading it right build a 4ft high wall and skin it. would the bottom need to be doubled? build the whole thing out of 2 x 6 and set it on 6 x 6 posts?

How about building a plywood skinned "box beam" that acts as the structural support and as the railing for the kids. A four foot high stick built wall with a nailing strip on the lower section for joist hangers and skinned with 3/4" plywood on both sides will hold almost anything you want to put up there. I've built them to span double garage door openings, hold up the roof joists, add insulation against the weather and hide wiring for years. Best part is they don't require a crane to put them in place.

 

[Cryptic1911]

We have a 30ft 7x24" glulam beam in our garage for a clear span, then 15' 2x12's off of that the other direction

 

[Hades12]

Stopped by the scrap yard and they had a few I beams that would work but they have already been sold.

Would the main beam out of a mobile home work? I know where a set is if I can get to them through the bushes.

 

[samert111]

When I put the 8' extension off the back of my 26' wide PB, to eliminate the 3 posts they used 2 - 16" x 26' LVL's side by side nailed together to tie in the rafters for the new roof.

 

[tlmartin84]

The LVL's are nice and easy to work with, but when you start getting over 16" in depth dropping back to a shorter steel beam tends to be more cost effective.

For ease I would order 2-1.75" x 16" LVL's. Place one, and then nail the other one to it placing to min #12 nails every 12", 2" from each edge (If that makes sense). Then use joist hangers to support 2x10's on 16" center with 3/4" sheeting. ANYTHING over 10" on 16" centers is COMPLETELY OVERKILL and a waste. I would drop back to 2x8's on mine.

The ends need to rest on post or have a steel connection (like a joist hanger, only beefier) to tie into the walls.

What size are the mobile home beams?

 

[buening]

Is this a business or personal use building? Have you checked to see if a construction permit is needed, since this will be structural?

My biggest warning will be to make sure you have your connections of the joists to the block wall (recommend not anchoring to wall and rather have another LVL at the wall face), as well as the connections of the LVL to the columns done correctly. Simpson makes some pretty good brackets that you might want to look into. Also make sure your columns are big enough to handle the loads. You are looking at roughly 3000 pounds per corner column assuming 50psf dead + live loading on a 23'x10' "deck".

Regarding the mobile home beams, they are typically bulky enough but you really need to know what size they are.

 

[Bluesbarrister]

No matter what you end up using for the main beam - why don't you consider using wooden I-beam joists for the floor? Way stronger than dimensional lumber and as a previous poster said, you could cantilever a few extra feet for more space upstairs. I'd go to your local truss manufacturer and ask for their opinion.

Da new guy.

 

[magicdrafter]

Why not use 23' floor trusses 12" tall & space 12" o.c. build 2x4 walls at either end w/ sheeting. Verify rating w/ truss company. Floor would be clearspan without posts & you would distribute the weight evenly with the wall. Overall would be less money than beam & joists & much less time to set. Just my 2 cents.