Reverse Engineering Fabric Building

• Monday at 11:05 PM

• #41

Ron247

Structural

Jan 18, 2019

1,462

US

Tube thickness could be a nightmare. Mass produced structures might have 16 gauge in one place, 12 gauge in another; their fab drawings and part numbers keep them separated. You will have no idea what they are.

 

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• Tuesday at 11:05 AM

• #42

LittleInch

Petroleum

Mar 27, 2013

23,123

GB

I think what everyone is trying to tell you is that you've bought a pup.

Whether it really needs a "building permit" is questionable, but this is a product designed to a very low price and intended for locations and usage where it doesn't really matter if it falls down in high winds, heavy rain or snow.

When you can buy a brand new one from a known supplier, delivered with full instruction manual for $9000, it seems to make trying ( and paying more money - what did you buy this thing for??) to get this second ( or third) hand bunch of parts to meet any sort of known code or standard or even just a "looks ok to me" form of comfort from an engineer, very poor value to me.

And then it is clearly NOT able to actually withstand any decent snow load, you do wonder if anyone else puts these up and relies on them during the winter??

I looked up what 60lbs/sqft was in terms of snow and "settled snow" comes in at about 4 feet (!). The idea that a fabric covered flimsy tent like shed can handle 4 feet of settled snow is for the fairies quite frankly. But if the agricultural "code" angle says its up to you, try it and see if it survives a winter, then come back next year and tell us we were all wrong.

 

Last edited: Tuesday at 4:22 PM

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• Wednesday at 2:05 AM

• Thread starter
• #43

C

cjowett

Structural

Jul 12, 2025

11

So I spoke with the building department coordinator today and explained that the drawings aren't available. Her response was that the township can't legally issue a permit without the stamped drawings so I have two options: come up with the drawings; or withdraw the application and put the building up without the permit.

 

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• Wednesday at 2:32 AM

• #44

Aesur

Structural

Jun 25, 2019

894

AZ, US

XR250 said:

That fee just seems crazy to me. If your rate is $250 per hour that is 160 hours of design and site time. C'mon seriously?
You would find out pretty early on in the process that the job is basically impossible anyway.

Click to expand...

I wish my bill rate was that! I estimate more than 160 hours when knowing you also have to draw it, not just engineer it. It's not as easy as you think by any means, I'm going off experience with having done things sim to this before and having learned the lesson of going too low.

 

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• Wednesday at 12:33 PM

• #45

LittleInch

Petroleum

Mar 27, 2013

23,123

GB

I'm sure you've seen this, but for everyone else, it does indeed look like any structure for a farm in Ontario which could have someone inside it, needs a building permit.

Interesting article here about SB-11 - requiring a "competent designer" if you need to avoid the building code.

Agricultural Post Framing - Elite Agri Solutions

Elite Agri Solutions strives to provide background information on topics which are hard to research. In cases where no reputable print resources were available for us to reference, we interviewed industry experts, so it is inevitable that the contents of this document will contain inaccuracies...

eliteagrisolutions.ca

I would not ignore the requirement for a permit, especially now you have raised one. Unless you live out of sight of a public road.

 

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• Wednesday at 1:59 PM

• #46

Ron247

Structural

Jan 18, 2019

1,462

US

LittleInch said:

I looked up what 60lbs/sqft was in terms of snow and "settled snow" comes in at about 4 feet (!). The idea that a fabric covered flimsy tent like shed can handle 4 feet of settled snow is for the fairies quite frankly. But if the agricultural "code" angle says its up to you, try it and see if it survives a winter, then come back next year and tell us we were all wrong.

Click to expand...

The 60 psf was an unimaginable load for a building who's selling feature is cheap cost. But as I said, sales have a lot of gimmicks. What if only the fabric (which I think is a PVC product), can take 60 psf USD load at the distance it spanned BUT NOT the frames. They would play with the wording enough to make "sales point". I also noted that TMG referred to theirs as "heavy duty".

 

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• Wednesday at 2:05 PM

• #47

Brad805

Structural

Oct 26, 2010

1,558

CA

Keep in mind now that you have started the process it is on record. If they find out later they can put a notice on your title and that can have impacts if you ever want to sell. I would re-list this on facebook or if you want to find an engineer to look at this and toss $5-10k down the drain to discover it needs a ton of reinforcing, you can do that and then list it.

You might be able to find a PEng for this task at PEO. Their website search is quite terrible.

 

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• Wednesday at 3:50 PM

• #48

Ron247

Structural

Jan 18, 2019

1,462

US

In the end, I doubt whoever you get to engineer it, it will not work for some very simple and practical reasons.

1. You cannot easily get the actual tube thickness. In a mass produced environment, they tend to minimize material whenever possible. One frame alone could have 6 different potential thicknesses per outer tube size. They can easily keep up with those during fab, but not easy to field measure.
   1. Your alternative is to be conservative to cut down field measurement costs.
   2. Even the perimeter tube on the frames is probably spliced. Each side of a splice may be different thickness.
2. Are the end frames slightly lighter than interior frames since they are "half a bay" loading? If they are, another set of measurements and thicknesses because you have no way of knowing.
3. You also must review condition since it is part the responsibility. That includes welds.
4. Testing costs for steel grade and again, being conservative because each sample may yield different results.
5. Drawing cost. I know of entire PEMBs that were stock sizes they had engineered years ago. On those, there was not one engineering calc, detail drawing or primary drawing that was done for that very job. They were all xeroxed from the original design.
   1. You will pay for a lot of drawings done for your job. That will be the lion's share of the cost.
6. Analyzing connections will eat another hole in the budget. Determining fastener allowed strengths, diameters etc.
7. When you are conservative on all assumptions or "ball park estimates", the final product will most likely not check out. Mass produced items such as these do not tend to have a lot of added "umph" to them. So, taking something that barely works with everything known, and trying to reverse engineer while having to be conservative, tends to be a waste of money.
   1. A classical PEMB is far easier to field measure and analyze than your tube frames and their connections.

 

Last edited: Wednesday at 11:43 PM

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