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:

 

[RabbitHutch]

Hi again folks. I've finally finished a really, really big project this year and am ready to move on to the next big thang in my life... a shop. a shop that's warm in the winter and cool and breezy in the summer. Is that too much for a girl to ask for.

So... I have some questions so I can get my materials together.

1. Do I need that pink stuff under the 2x4 that's j-bolted to the slab? I saw it on ustmd's post for his bldg. Is that just for drafts?

2. 5/8"plywood tongue-grooved for roof? Is there a grade like A/D or A/C or something I should get?

3. 1/2"plywood for walls... is that tongue-grooved as well or regular? Grade?

4. The walls will NOT bare the weight of the roof. The poles will hold up the roof. What on-center spacing for the studs can I get away with? I will be insulating and don't really want to cut width of insulation to fit, but I don't want the walls to be flimsy between the poles. I was thinking 24"OC too big and maybe going with 19"OC. Thoughts ??

5. I have read folks screwing the sheet metal directly to the plywood without a strap/girt. I don't know why, but I am wary of this. I guess for the same reason I want to put straps/purlins on top of the roof decking. Any thoughts or reasons for one way or the other would be appreciated.

Thanks all,

Michele

 

[ustmd]

1. Do I need that pink stuff under the 2x4 that's j-bolted to the slab? I saw it on ustmd's post for his bldg. Is that just for drafts?

2. 5/8"plywood tongue-grooved for roof? Is there a grade like A/D or A/C or something I should get?

3. 1/2"plywood for walls... is that tongue-grooved as well or regular? Grade?

4. The walls will NOT bare the weight of the roof. The poles will hold up the roof. What on-center spacing for the studs can I get away with? I will be insulating and don't really want to cut width of insulation to fit, but I don't want the walls to be flimsy between the poles. I was thinking 24"OC too big and maybe going with 19"OC. Thoughts ??

5. I have read folks screwing the sheet metal directly to the plywood without a strap/girt. I don't know why, but I am wary of this. I guess for the same reason I want to put straps/purlins on top of the roof decking. Any thoughts or reasons for one way or the other would be appreciated.


Michele

Hiya,

It looks like everything is progressing well.

To give you some ideas:

1. The pink stuff does stop drafts, but it also functions as a moisture barrier between the slab and the wood. Even with pressure treated wood, you do not wantwood in direct contact with concrete. You can also use a zig-zag bead of construction adhesive. The pink stuff is not expensive, I think I paid $5 for a 50ft roll.

2. Tongue in groove material is for floor decking (for example on a second floor). For the roof you want to use OSB sheathing (most like 9/16ths--depending on the spacing of the rafters). Also, you want to get the panel spacing clips for the sheathing. The clips are in the section of Home Depot or Lowes that has the Strong Tie parts. You want some spacing between the panels for ventalation.

3. You should use OSB sheathing for the walls as well (no tongue in groove). You can use plywood, but it will be much more expensive (OSB will be ~$10 for a 4 x 8 sheet vs $20 (or more) per sheet for plywood).

4. How tall are you walls? Are you using 2 x 4 for studs? 24" OC should be okay. You will need to use a thicker sheathing 9/16 or 3/4).

5. I can offer no intelligent opinion on this. I did not use purlins/straps under my metal roof. I have seen people go either way.

 

[RabbitHutch]

Here is the pic of existing cover removed. I've ordered the material and will start the beams for the roof in the near future.

Thank you everyone in advance for observations/comments/recommendations.

 

[RabbitHutch]

2x12x24's were delivered. I start making the double beams.

 

[ustmd]

2x12x24's were delivered. I start making the double beams.

Having just lifted 2 x 10 x 24 for my shop, I hope you have help for those.

Good luck.

 

[RabbitHutch]

I have a beam question:

the beam is 2-2x12x36'. It will be 4 pieces 14'-22' on one side and 22'-14' on the other with plywood in the middle. Bolted every ~12' to a post.

At 10# dead load (more probably 7#) each span will carry ~1500#.

Q: Do I still need to put a crown the beam? and is it possible to do so with the design mentioned above? Will it sag that much?

Thanks. Someone mentioned this and it has me worried.