# Is 4-12 pitch OK for 24ft Truss span?



## Sleeper (Mar 24, 2009)

I'm designing my New shop Framing for a 24x50ft shop and when I drew up the truss, it didn't look right. I just want to run it by some people in the profession for some advice before I commit myself to this plan.


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## Steve Neul (Sep 2, 2011)

The area where you live the 24' span should be fine. You don't live in an area with heavy snowfalls. The pitch of the roof wouldn't affect the span as much the strength of the trusses and the spacing. It's the amount of weight each truss is expected to hold. If you used a metal roof you could use fewer trusses. Part of my shop is 32'x42' with a metal roof and I just have two trusses. They are much heavier trusses than bought trusses though.


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## Sleeper (Mar 24, 2009)

We don't have to worry about snow loads. I drew the truss from a photo I saw on the internet without know how they are supposed to be. I used to build garages when I was young and the trusses were always pre-built and delivered to site and placed on the top plate. I never really paid any attention to them and just set them up and nailed down the sheeting. 

The reason why I questioned the pitch was because when I first drew the truss, I only had a 1' height and realized pretty quick that would not work just by the looks of it. Then I remembered everybody talking about a 4/12 pitch which only made sense that would affect the span. I just didn't have the anything to back it up.

I haven't thought about the roofing material yet and just assumed composition roofing, but you got me thinking. I have to check into metal roofing. Thanks!


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## TimPa (Jan 27, 2010)

we are building a 24'x50' pole building now with 4/12 trusses 4' oc, metal roof in a snow climate. the building was engineered so I have to trust the design. there is a lot in truss design - layout, wood type, wood dimensions, attachment methods, etc. I would do my homework there.


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## Sleeper (Mar 24, 2009)

TimPa said:


> we are building a 24'x50' pole building now with 4/12 trusses 4' oc, metal roof in a snow climate. the building was engineered so I have to trust the design. there is a lot in truss design - layout, wood type, wood dimensions, attachment methods, etc. I would do my homework there.


Thanks, I don't know yet what is available where we are moving to, but I would rather have a company build them and stack them on top for me. I'm looking into metal roofing now but I'm a little trouble finding them in the area unless I pay big. 

I haven't looked into pole barns, there are a lot of farms all around me so they should be available. The last pole barn I saw had a dirt floor. I guess I need to look into pole barns as long as I have a polished concrete floor.


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## Steve Neul (Sep 2, 2011)

The 4/12 or more pitch is what shingle manufactures recommend. In your area that is your only real concern regarding pitch. Some places in the country that have heavy snow they like a steeper slope because it gives more strength to the trusses or roof framing. 

As far as using metal for the roof there isn't anything wrong with using the R-Panel metal like they use on metal buildings with wood framing. This is what I've done in my shop. I still use the metal building insulation but the framing is wood. The first picture is the old part of my shop. I have an area 33'x42' which just has the two trusses. The rest of the framing is just 2x6's. The second picture is a new section I'm trying to add. It's an area 28'x28' with two trusses. I omitted the skylight in the new section because of condensation and put the skylight material at the top of the wall instead.


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## Sleeper (Mar 24, 2009)

Oh WOW Steve, that looks nice. I'm trying to save as money as I can because its just going to be for my own personal projects and it doesn't have to be pretty.

I like the skylight and I thought I wouldn't be able to have them with a metal roof. Thanks for the photos that really helps me a lot.


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## Steve Neul (Sep 2, 2011)

Sleeper said:


> Oh WOW Steve, that looks nice. I'm trying to save as money as I can because its just going to be for my own personal projects and it doesn't have to be pretty.
> 
> I like the skylight and I thought I wouldn't be able to have them with a metal roof. Thanks for the photos that really helps me a lot.


This is the type material I used for the skylight. http://www.metaldeck.com/fiberglass-r-panels-skylights.html It's the same pattern as the metal but made of fiberglass. You just have to be careful walking on the roof because the fiberglass panels won't hold a persons weight. I really didn't care for the skylights after I did it. It lets in a lot of light but in winter condensation builds up on the skylights and drips on everything below. This is why I put the fiberglass on the walls on the new build.


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## Sleeper (Mar 24, 2009)

Steve Neul said:


> .......... It lets in a lot of light but in winter condensation builds up on the skylights and drips on everything below. This is why I put the fiberglass on the walls on the new build.


Oh! :surprise2: That reminds me of a steel building I put up 40 years ago for tractors. The one problem was that during the winter the condensation was so bad that they had to park the tractors so that water wouldn’t cause any damage. Some of the farm equipment actually had to be covered with tarps during off season. 

This might cause me some concern because I don’t want to have any water in my wood shop.


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## Sleeper (Mar 24, 2009)




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## Sleeper (Mar 24, 2009)

Ok I think this might be my solution although I haven't priced it. I found it interesting that they angled so the roof is vented.


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## Steve Neul (Sep 2, 2011)

Sleeper said:


> Oh! :surprise2: That reminds me of a steel building I put up 40 years ago for tractors. The one problem was that during the winter the condensation was so bad that they had to park the tractors so that water wouldn’t cause any damage. Some of the farm equipment actually had to be covered with tarps during off season.
> 
> This might cause me some concern because I don’t want to have any water in my wood shop.


Where the building is insulated there isn't any condensation. It's just the fiberglass skylights. It's not a lot but I have to locate my equipment where it isn't under one.


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## woodnthings (Jan 24, 2009)

*you don't need sylights*

Build your building so the walls are 10 ft tall at the roof. Side it 8 ft up with solid material, wood, metal, what ever. Put your clear fiberglass on the remaining 2 ft of wall high up to let all kinds of light in and keep prying eyes from looking in.


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## Sleeper (Mar 24, 2009)

woodnthings said:


> Build your building so the walls are 10 ft tall at the roof. Side it 8 ft up with solid material, wood, metal, what ever. Put your clear fiberglass on the remaining 2 ft of wall high up to let all kinds of light in and keep prying eyes from looking in.


I like it! I was thinking of using those windows that they put over shower tubs, but was shocked at how much they cost. This approach works better for me because then I can have more overhead room. My original plan was to use plywood siding, but I couldn't find any long sheets. I guess I could use horizontal siding but was afraid that scorpions would be able to squeeze through and thought it would be easier to seal the seams of plywood.

Wow! So much to think about. Thank god Sketchup is easy to make modifications. :smile2:


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