3-car shop

[RabbitHutch]

Hi everyone,

I've been reading many posts here regarding pole barns and proceedures, etc. I have some questions that I haven't been able to wrap my head around the answer. So, I would like to post them since everyone here has great opinions and ideas.

Background:
There were existing poles in place when I bought the place (12x24 on 12'pole spacing). They have the tin wrap in the pic. So I had a slab poured around the existing poles and had some new ones placed. It's ~24x36. The use of this building is intended as a garage/shop. The roof was going to be shed type with a 1:12pitch, but now I would like to make the building a little better. So, that went from a basic bldg to being insulated and possibly a room on top. So, here are my questions:

If I trim the poles level and put attic trusses up, how much overhang can I have (trying to make the attic/room as tall as I can) and do they have to be placed 2' OC? Or... is the 24' span just not big enough to make a stand up room (like a sleeping loft)?

If I wrap the bldg with moisture barrier, where does the moisture barrier go? and should I just side it with osb too? Girt/wrap/metal? wrap/girt/metal? Or... can I just put insulation (like that foam board stuff) on the inside of the girt after walls are up and be done with it?

Thanks for helping I've been at a loss with steps.

Michele

 

[MikeD74T]

Lots of unknowns for a real good answer but: here's a link to various truss types. A full gambrel will give you the most space short of going to a full second story. Question is; will your posts support the weight of added structure & intended occupancy? Do the posts sit on solid footings? what kind of wind load/bracing will you need?
Overhang is obtainable but must be designed into truss application. Trusses rely on a specific geometry & can fail slowly or catastrophically if incorrectly installed. Most triuss companies will provide a design for your aplication.

Moisture barrier is primarily to keep the normal room moisture from penetrating to & saturatung the insulation/framing. Moisture trapped in the wall causes loss of insulating factor & rot. Rigit foam (vs fiberglass)won't absorb enough moisture to substantually lower heat transfer but can still trap moisture in contact with structural wood. MikeD74T

 

[ustmd]

Question is; will your posts support the weight of added structure & intended occupancy? Do the posts sit on solid footings? what kind of wind load/bracing will you need?
MikeD74T

Ditto--also, there are about a million other qutions--type of roofing, what is the room for? YOur are insulating, will there be power and HVAC?

All of this is important because it is goign to add weight to that sleeping loft and if the basic structure is not correct, it wll all come down--either slowly or quickly.

Can I ask if you have done any type of projety like this before? I am all for figureing it out as you go, but you might need some on site advice.

 

[ustmd]

One other thing, just looking at the span tables for floor joists, for the 12ft span, you will need either 2 x 8 (12 inches on center: 12 OC) or 2 x 10 24 oc). Those will be some heafty rafters.

 

[RabbitHutch]

Thanks. I guess you are right... too many unknowns. I will be ready to start this project in December and am still in the "what if" stage to gain more room up top for the extra $.

If the truss idea is too complicated and/or I can't get the desired results then it will be a plain old roof. I will still be happy with that.

I would still like to insulate the building though. Can it be done after construction with the same r-value results? or should I take the time during construction?

 

[RabbitHutch]

ustmd, after posting the original question(s) I found your building. This is more or less what the design is now. A shed type roof originally used for an RV or something. The tin currently installed will come down and everything will be redone "correctly" and trued-up.

The building will really be to work on my VW Rabbits (Rabbit Hutch) and other vehicles. Also, for secured storage.

It will have electricity for sure and hopefully H2O one day.

I wanted to insulate so winters wouldn't be so darn cold (and damp). I live outside Houston and when that winds comes off the gulf in winter it hurts the bones. So, I wanted to put a wood stove in there, but not too much more. If attic will not work I will span using 2x12. This I would really like to insulate and don't want the moisture problem. Would this combo work?:
2x12
decking
felt paper
2x4 purlins 24"OC (adds to wind load i think I read 20mph)
metal roof


I don't have a lot of property so I was just trying to maximize the results.

 

[ustmd]

ustmd, after posting the original question(s) I found your building. This is more or less what the design is now. A shed type roof originally used for an RV or something. The tin currently installed will come down and everything will be redone "correctly" and trued-up.

The building will really be to work on my VW Rabbits (Rabbit Hutch) and other vehicles. Also, for secured storage.

It will have electricity for sure and hopefully H2O one day.

I wanted to insulate so winters wouldn't be so darn cold (and damp). I live outside Houston and when that winds comes off the gulf in winter it hurts the bones. So, I wanted to put a wood stove in there, but not too much more. If attic will not work I will span using 2x12. This I would really like to insulate and don't want the moisture problem. Would this combo work?:
2x12
decking
felt paper
2x4 purlins 24"OC (adds to wind load i think I read 20mph)
metal roof


I don't have a lot of property so I was just trying to maximize the results.

I hear what you are saying.

Trusses will work or the material list you have.

How tall are the poles? I am asking because I thought you mentioned you wanted a low slopw roof--1/12 pitch, which may affect how much room you would have in the attic.

It is was my building, I would put radiant barrier OSC sheathing on first (then your felt paper, purlins, etc). Three reasons:

1. Wind shear/structural benefit
2. Radiant barrier/insulation benefits (it does make a difference here in TX)
3. Support the roofing felt over time--the wind moving between the metal and the purlins is going to cause that felt to start "flapping" and moving over time and it would drive me nuts when I was in there working. :confused2:

For the sides, I would definitely sheath it and use the house wrap, then what ever siding you want (metal, hardi plank, vinyl, etc).

For insulation, that can always be added later. Unless you want to do foam sheets on the outside, you do the insulation from the "inside" of the building only after you have created a weather tight skin on the outide.

 

[RabbitHutch]

Thanks, it's soaking in finally. Good tip for the radiant barrier. I never would have thought of that. and yes Texas is a beast for the sun.

The pole have varying heights and will have to be trimmed accordingly. So, if I stick with the shed type roof then no attic. I will just "hang" some plywood from the rafters to put my coolers and such on.

Thanks again. I know this isn't a glamorous project. I had two people quote me $5-7K just for labor and that was barn product only. Metal roof and sides. So... it does make a difference when it's yours and I'm not interested in being debt for something like this.

When I decide everything and start the project I'll post pics. I'm sure I'll need some armchair coaching.

Michele

 

[tjse9006]

I'm not an expert by any stretch of the imagination, but I would put the headers on those poles asap. I've had them twist on me after a little time and had a mess. TC

 

[gazoo1]

keep on working gonna look great when your done moisture barriers are always installed on the warm side of the building:thumbsup: