Questions for the Architechs/Engineers

[mw67rs]

I am in the very early planning/dreaming phase for building my workshop/garage. I want to build a 30x40 shop. I know the bigger the better but that is all I think I will be able to afford and I think it will serve me well for several years. But I know that at some point I may want more space so I would like to build the shop so that if I do want to add to it later I make it as easy as possible. I want to have a large entertainment room above the shop for the family to use. I am thinking of having 9' high ceiling in the shop and the ceiling in the upper room will start at 6' and go up to 9'.

I am thinking of making the 30' wall the load bearing walls so if I decide to add space it will be easier to expand the shop to 40x50 or 40x60. Is this the right way to do it. It does make the initial build a little more difficult because the upper floor joist have to span 20' instead of 15' if I made the 40' walls the load bearing walls. see pic below.

http://www.garagejournal.com/forum/attachment.php?attachmentid=296221&stc=1&d=1385265496

I am thinking that I would build 9' high walls, then add the upstairs floor joist on top of these walls and then add 4' high walls on top of the upper floor. Is that how it should be done?

I am also assuming I will need an I-beam running the 30' length to support the upstairs floor joists. I couldn't find anywhere how to accomplish a 40' floor joist span so I think I will need the I-beam. Is it possible to have the floor joists mount inside the I-Beam (see photo above) to minimize the room lost by the beam and floor joists.



Also, I would like to maximize my usable space upstairs. Can I have a roof that is not supported by rafters? Instead use 2x? run from the walls to a beam at the peak of the roof?

I know I will need to have plans drawn up that will cover all of this before I start building but I am many months away from that point and want to know how some of these things should be done. Thanks for any help anyone can provide.

 

[Trochu]

A couple questions:

-Will you have to build this to any sort of code or are you mainly concerned about safety/quality of work? If it will have to be build to local building/municipal code, what members say won't matter; and,

-If there is no building code, regarding the rest, it depends upon a variety of factors mainly pertaining to your loading situation (snow, wind, dead/live, beam size, etc.). If you live in Fernie, I wouldn't be building a roof without proper trusses.

 

[keelan]

If you live in Fernie, I wouldn't be building a roof without proper trusses.

Fernie? Odd example to use. Having grown up in Fernie and moved on to warmer climates, I'm always surprised at how under-built things seem in the warmer areas.

 

[mmhouse]

Talk to your local pro lumberyard or truss manufacturer about attic trusses. It'll save you a lot of hassle with the beam both now and later if you add on. You may get a little less space than you have pictured upstairs but in exchange you won't have any posts in the garage.

 

[Architorture]

Are you expecting a 30' clear span for the main beam? If so it's going to be a lot deeper than what you have pictured....

 

[jkwilson]

+1 on Attic trusses.

 

[mw67rs]

Thanks for the replies. I currently live in MA but I am planning a move to NC or SC. So I shouldn't have any snow loads.

I don't know about any code issues but I understand they can change all my plans. I won't be able to find out about code issues until I determine exactly where I will be moving.

I was hoping for a 29' clear span for the I bean so I wouldn't have a post in the middle of the shop but I don't know if that can be done.

What is the benefit of attic trusses over what I was planning. I know they would cost me open area upstairs but what would they get me?

 

[stingry]

Thanks for the replies. I currently live in MA but I am planning a move to NC or SC. So I shouldn't have any snow loads.

I don't know about any code issues but I understand they can change all my plans. I won't be able to find out about code issues until I determine exactly where I will be moving.

I was hoping for a 29' clear span for the I bean so I wouldn't have a post in the middle of the shop but I don't know if that can be done.

What is the benefit of attic trusses over what I was planning. I know they would cost me open area upstairs but what would they get me?[/QUOTE]

Trusses can easily span the 40' span plus you can spec attic trusses as mentioned above that will get you an upstairs room.

Cheers
Steve

 

[Sheriff245]

+1 on attic trusses. If you're doing the I-beam thing, you can use steel joists for minimal loss of space in the attic.

Also, depending on where you relocate, you may need to build your foundation deeper in the ground to protect from freezing. In that case, you should consider a structural slab for ground level, which will double your work area without having a larger building.

 

[Nowater]

1. Look into the hurricane wind speed zones where ever you move in the Carolinas.
2. The walls as you have drawn them act as a hinge where they join and meet at the ceiling, a weak spot. There are ways around this, but also consider 14' studs and balloon framing.
3. Consider trusses sized to meet your upstairs loads.

 

[mmhouse]

What is the benefit of attic trusses over what I was planning. I know they would cost me open area upstairs but what would they get me?

The biggest benefit is no post in the garage. You will either need a post for that span or the beam would be ridiculously deep (and expensive). Also less roof framing.

 

[jkwilson]

Thanks for the replies. I currently live in MA but I am planning a move to NC or SC. So I shouldn't have any snow loads.


What is the benefit of attic trusses over what I was planning. I know they would cost me open area upstairs but what would they get me?

In the Carolinas you need to worry about wind from hurricanes.


Attic trusses will be a lot cheaper. Rafters and joists with the kind of lengths you are looking at are going to be expensive. Trusses uses short pieces of lumber.

It looks to me like your drawing is way out of scale. Draw it out on graph paper and I think you'll find you need a lot more pitch upstairs to have anything close to the room size you are hoping for, and you'll need a lot more height to get a 9ft ceiling because of the collar ties. I went through this on my house, which is a Cape Cod. Anything less than a 10/12 pitch kills your upstairs space.

 

[Riverside]

I am planning a move to NC or SC. So I shouldn't have any snow loads.

If you move to the mountains of NC, you will have snow loads.

 

[hippie2cams]

It also snows quite frequently in S C

 

[rburke65]

I would think trusses also. I think any lumber yard will be able to show you a printout on an attic truss to span your 30', or wider, span and your required, or desired, ceiling height.

 

[theoldwizard1]

For the maximum amount of attic space make the roof out of Structured Insulated Panels (SIPs). This does require a different building technique. You have to have a true ridge beam supported on each end by a proper column. The ridge beam is typically something like a 4x12 glulam.

Roof panels would probably be 4'x24', one piece. Obviously a crane is required to install the ridge beam and the roof panels.

The big bonus is, once installed you now have a very well insulated roof !

 

[bczygan]

It's real simple.
When you decide exactly WHERE you are going to build (The exact lot).
Zoning will tell you WHAT you can build, how big, tall and where you can locate it on your lot. It will also tell you what uses you can make of the lot.
Applicable building codes for that jurisdiction will tell you HOW you may build.

Then it is just a matter of setting a budget and determining if you can accomodate all your wishes within that budget.

An Architectural designer will layout your spaces within the constraints of zoning and building rules, to accommodate the functions needed. He, or an engineer will determine the most appropriate type of structure to accommodate all of this. They will size members and choose materials to best meet your desires with an eye toward cost. Sometimes steel is the material, sometimes engineered wood of some kind, sometimes dimensional lumber. It all depends on functions, loads, uses and codes.

You can do almost anything. Everything you do costs money. The more extreme the task, the more it will cost.

 

[wssix99]

I am thinking of having 9' high ceiling in the shop and the ceiling in the upper room will start at 6' and go up to 9'.

That isn't enough! You'll want more, I think. Also, if you put in a car lift at some point, you'll want to carve out a section up above for more headroom. It's such a big shop, that I think a 9' ceiling would feel a little cave-like.

I am thinking that I would build 9' high walls, then add the upstairs floor joist on top of these walls and then add 4' high walls on top of the upper floor. Is that how it should be done?

If you want clear spans, you can also run multiple beams across the long way and then span joists in between the multiple beams - but this would be a lot more expensive. I'd guess the way you have it laid out would be the most economical.

I am also assuming I will need an I-beam running the 30' length to support the upstairs floor joists. I couldn't find anywhere how to accomplish a 40' floor joist span so I think I will need the I-beam. Is it possible to have the floor joists mount inside the I-Beam (see photo above) to minimize the room lost by the beam and floor joists.

We just installed some floor trusses spanning 30' for our house and our truss guys said we were starting to "push it." They are 16" deep and have some noticeable give to them in the middle of the spans. (I'd prefer a more solid feel to the floor and hope that things will stiffen up a bit when we get the walls in.

I think you are wise to expect that a center beam is the way you'll end up.

You can put the trusses on the beams a number of ways. You can put them inside the flanges for a "bottom chord bearing" truss, but the steel beams aren't that precise. The sizes are nominal and can vary by a good amount beam-to-beam. Attaching the trusses to the bottom flange of the beam is also problematic. You can nail through the steel, but that flange is the one that takes all the bending tension of the load. (I and my engineer-of-record prefer not to do this method and/or nail through the flanges of the steel.) If you leave a bay open to get some more head room in your shop, you also introduce some odd twisting in the beam that has to be accounted for.

I think you will find top chord bearing trusses are the way to go. They should be easier to install, easier to engineer, and should provide you with additional flexibility of design. Simpson makes special truss hangars that lap over a wood top plate placed on the beam and bears all the weight on the top.

For steel beam depth, you'll have a lot of flexibility if you can put in columns. You'll find that each column will drastically reduce the depth (and expense) of your steel beam. In addition to loosing the floor space to the columns, you'll also want to consider their impact on concrete control joints. You'll have control joints radiating out in 4 directions from each column, which could impact how you install lifts or other equipment in the shop.

You also don't necessarily need to evenly space the columns out either. I have two in my garage, holding up a massive steel beam with a two story solid concrete wall on it. The architect put the columns right where my car doors would open, but I was fortunately able to move them both several feet to allow for easy opening of doors, etc.

 

[theoldwizard1]

We just installed some floor trusses spanning 30' for our house and our truss guys said we were starting to "push it." They are 16" deep and have some noticeable give to them in the middle of the spans.

My buddy built a barn a few years ago with floor trusses for the second floor where he stores hay. A LOT OF HAY ! These are fresh cut, field dried rectangular bales so they still have a fairly high moisture content, which of course adds to their weight !

Just guessing but those floor trusses about the same depth (maybe 18-20" ?), but they are spaced every 16" O.C.

 

[wssix99]

I just thought of something. I expect the cost will be prohibitive, but it is an interesting technology.

If you want a thin floor, you can go with cross-laminated timber. http://www.naturallywood.com/emerging-trends/cross-laminated-timber-clt

The depth is much less than a truss, but they are heavy and need a crane to place. (You may also still need to install a ceiling underneath to get the proper fire rating for your shop. They seem to be en vogue now in the architecture world and are being visioned as a way to build super tall timber buildings.

 

[PetesPonies]

I just moved from Maryland to SC. The snow down here is a joke, no loads to speak about. That's one reason I'm here. I went to college here and have been down here once a month for the last 6-7 years working on my property. Building here is pretty easy IMO, compared to Maryland. I've done plenty of it in SC, still building my house as I type. 56x64 garage is done. Go with the attic trusses, makes thing easier from the beginning.

 

[jkwilson]

Did a real quick sketch while I was stuck on the phone in a conference call.

With a 6/12 pitch, you'll only have about a 10ft width of 9ft ceiling upstairs. One thing to consider to increase this is a saltbox style roof, where you basically raise one wall up to get more headroom in half the space.