High Snow Load Building

[chris the wrench]

Backstory: Im wanting to build a 20' wide by 24' deep with bottom of trusses at 14' rv/truck storage cover. No walls, no doors, no siding(for now), just a roof over a gravel floor. We live in an area that gets quite bit of snow. Our Ground snow load is 108 psf, unheated roof snow loaded is 82 psf. I've drawn and built several pole structures in other areas that didn't have the snow load, but at my home the county requires an engineered stamp for roof and walls. My profession is working on houses/building decks, Ive got the hammer and saw skills but I primarily worked in a different state before relocating back here and I don't know many professionals in this area.

I contacted 6-8 building engineering firms in my area(Central Washington). 2 bothered to respond. A larger company said yes they could do the drawings $3000. A one man shop responded and said yes, $950. That was back in early Jan. We agreed on a price and a 3 week timeframe to delivery. He has since disappeared, doesn't answer phone or emails. I didn't pay him anything, so Im only out my time and frustration.

Id prefer to build this structure with 6x6 posts, 2x lumber and trusses that I can obtain locally, but Im starting to consider a metal tube building kit. Versatube can supply a structure 'designed' to my snow and wind loads, and stamped engineering drawings(I think those were a $700'ish additional). During my research Ive seen quite a few crushed versa tube structures on the internet from snow loads and pissed off customers blaming the company. I have no way of knowing what the actual specifications were on those failed buildings, but it's the internet and facts frequently get left out.

Ive contacted a few of pole barn kit places, but I haven't gotten too many solid answers yet.


Questions:
Anyone with an engineered versatube type building and lives somewhere that gets a lot of snow? experiences?
Anyone know an engineer who could actually provide drawings for my project? Spending $3 grand for drawings seemed excessive to me.

Thanks


Edit:About 15 minutes after I posted those questions I was out walking the dog, and that's usually when my best ideas come to me. I called the local truss builder and it sounds like they maybe able to provide all the drawings plus the trusses. He hoped to have a quote ready for me on Monday!

 

[Rustyiron]

Sounds like you have the drawings solved, but I'm going suggest laminating 3 (or 4) 2x6's together for your posts. Stronger and much less likely to twist and bow. You probably have different materials and species of wood than here on the east cost, but around here treated 6x6's are usually SYP and finding a straight one even 8' long can be challenging let alone 16' or more. Laminating 3 or 4 ply's with PT 2x6 not only is stronger and more stable, (especially leaving 14' exposed with no purlins or additional framing)
but probably less expensive.

 

[chris the wrench]

Sounds like you have the drawings solved, but I'm going suggest laminating 3 (or 4) 2x6's together for your posts. Stronger and much less likely to twist and bow. You probably have different materials and species of wood than here on the east cost, but around here treated 6x6's are usually SYP and finding a straight one even 8' long can be challenging let alone 16' or more. Laminating 3 or 4 ply's with PT 2x6 not only is stronger and more stable, (especially leaving 14' exposed with no purlins or additional framing)
but probably less expensive.

I've been wanting to try the laminated posts where the top few feet aren’t glued together, so that you can cut the middle section to length and drop the truss right into the void left(bad explanation). Or leave the internal section and cut the two outer sections to support double trusses.

 

[mikester]

If you are buying and engineered building it will come with stamped drawings

 

[Rustyiron]

Chris I've been laminating 2x6 posts for a long time and never used a glue. Just a chit ton of ring shank or spiral pole barn nails. Even nail gunning with nails at opposing angles "stiching" them .

 

[oosik]

Contrary to several neighbors suggestions - I got a building permit to build my Pan Abode cedar home. This home came with a set engineer stamped drawings.

The permitting process took less than ten minuets because Pan Abode had most all their models pre- approved thru the county building dept.

It took longer to find a damn parking spot at the County Building Dept than to get my plans approved. As I remember - the permit cost $565.

 

[chris the wrench]

As I remember - the permit cost $565.

The permit for my rv/truck roof will be about a grand here. Im not thrilled about being close to $2k into this project before i even dig a hole.

 

[chris the wrench]

Chris I've been laminating 2x6 posts for a long time and never used a glue. Just a chit ton of ring shank or spiral pole barn nails. Even nail gunning with nails at opposing angles "stiching" them .

Are you a buried post kinda guy or brackets on top of cement piers? Ive done both based on customer desires. My in laws have a hay barn with posts that are buried and they are 50 years old. They easily have another 50 years of life, but they live in the valley where its alot drier.

 

[Rustyiron]

I've transitioned to no wood in the ground for anything but little sheds. Finding direct burry 2x6 is difficult, and I'm not sure what or if the chemicals they use today can compare to the old original CCA stuff.

 

[ponytug]

I've transitioned to no wood in the ground for anything but little sheds. Finding direct burry 2x6 is difficult, and I'm not sure what or if the chemicals they use today can compare to the old original CCA stuff.

Not much. In the lower 48, creosote treated wood is banned for most non-industrial uses. You can get treated wood with higher amounts of copper in it. (UC4B and higher) However, it can be hard to find. More here, if you are interested.

Wood Preservative Use Categories

Understand how Use Categories are the guidelines for determining the level of protection needed in the wood to perform in the specified conditions. See how the categories determine the amount or retention and the penetration of the preservative in the wood as defined by the AWPA.

preservedwood.org

I don't know the Canadian rules and availability.

I try not to have wood below grade if I can help it. Pressure treating only gets into the outer 1/8-3/8". If the wood subsequently cracks, or splits, untreated wood is exposed. I don't think it is a universally safe bet. I much prefer concrete piers, or concrete piers with a perimeter foundation to get the wood supports well above the rain or snow line.

You can boost your pressure treated wood with additional copper by painting or soaking the wood with 2% copper as copper naphthenate. It is the recommended treatment for any saw cuts into pressure treated wood.

All the best,

Peter