# A-Frame Greenhouse...



## 1969cj-5 (Sep 14, 2011)

I have been working on the idea of building a Greenhouse when I return from my current deplyment. I tore down an old Ferring Shed that was infested with Termites and burned the wood. I salvaged all the Tin and put that in my barn for later use. 

What I have left is a 40x25 Concrete floor and foundation footers. The Floor is sloped towards the middle and then a cement gutter runnning through the middle running lengthwise that is sloped towards the east end where a 6 inch drain runs out to an old leeching pond. The old owners raised pigs and would wash all the nastiness down the trench and it would flow to the old leeching pond. 

I think this foundation would work great for a greenhouse as there is a water hydrant and an 220 electrical connection that I did not remove or disconnect. The foundation also has good exposure to the sun as it was built with windows facing the sun all year on the southern exposure to keep the shed lighted and warm. 

I have been using some free time over here to study it out and I figure building an A-Frame style greenhouse so I can get the best benifit from the southern sun. It will also be able to shed snow buildup pretty well, last winter we got over 24 inches in one night. 

I am trying to figure out the pitch for the A-Frames so I can order them from an Amish neighbor that builds roof trusses. I would like to be ready to go when I get home. I want to get as much of a jump as I can on the growing season so I can have all my plants started when planting time for the garden comes around.

The problem is I have no clue how to calculate the pitch for the frames. I need to figure out how high I want the frames to be so I can get the ordered. Like I said the foundation is 25 feet wide, and I want 8 feet of headroom so I can mount light fixtures, fans and such. Any of you all have a clue how to calculate the pitch/height that I need the frames to be?

Any help, questions, comments and rude remarks are apreciated. Thanks in advance.


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## on_the_rox (Jul 17, 2011)

I have only seen a frames done with dimensional lumber (2xs) and tied with collar ties. I am sure they could easily be done with engineered trusses also, I just dont have the experience there. Just as an example though, with a 12/12 pitch and dimensional lumber with a 25 foot span you are looking at having an outside roof height of about 12.5 feet with an inside ceiling height at the peak of over 11 feet. This would be reduced in areas by the height of the collar ties holding the roof together but that could vary. If you were to bump that pitch up to say 16/12 that would give you an outside roof height of a little over 17 feet, an inside ceiling peak of about 16 feet, and more room for a higher "ceiling" structure. I would draw a few ideas out on paper and see what will best fit your needs. I am not a building expert, or a greenhouse guru, but I did do home remodeling for a few years so I hope I was a little help. Be safe over there.


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## on_the_rox (Jul 17, 2011)

Just a simple lesson on pitch too. Not sure if it is necessary but someone may benefit. On a roof the pitch is the ratio of the rise to the run. Basically that means the first number denotes the number of inches the the roof goes up and the second number denotes the number of inches that the roof goes across. So if you had a 4/12 ;itched roof the roof would start out at zero inches tall on the edge. It would be 4 inches tall at one foot over. It would be 4 feet tall at 12 feet over and so on. On a 12/12 pitch it would be 12 inches tall at 12 inches over and 12 feet tall at 12 feet over. I hope I am not talking down to anyone but I wanted to try to cover the basics to make sure you understood how the pitch ratio works. Hope this is helpful.


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## 1969cj-5 (Sep 14, 2011)

You are not talking down to me at all, I tried to google this but could not get my search framed the way I wanted it. Thanks, now you have me doing some numbers. :2thumb:


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## NaeKid (Oct 17, 2008)

I draw stuff in autocad all day long for my day-job .. it would be nothing at all for me to figure out the angles that you would want to use for an A-Frame greenhouse ....

What I would need is the size of the pad to start with the position that you would want the door-way to be placed (on the 25' or on the 40' face) and if you would want any "short-walls" for the A-Frame roof to sit on and finally - how high would you want the building to be?

I did some really quick calculations and based it on a short 4' wall at the base with a 16' rise (20' overall height) on the 25' width and got a _12 x 15 1/2"_ run x rise (or it works out to be a 52° slope). That would put the man-door into the side with the 25' width ...


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## 1969cj-5 (Sep 14, 2011)

NaeKid said:


> I draw stuff in autocad all day long for my day-job .. it would be nothing at all for me to figure out the angles that you would want to use for an A-Frame greenhouse ....
> 
> What I would need is the size of the pad to start with the position that you would want the door-way to be placed (on the 25' or on the 40' face) and if you would want any "short-walls" for the A-Frame roof to sit on and finally - how high would you want the building to be?
> 
> I did some really quick calculations and based it on a short 4' wall at the base with a 16' rise (20' overall height) on the 25' width and got a _12 x 15 1/2"_ run x rise (or it works out to be a 52° slope). That would put the man-door into the side with the 25' width ...


That would be great, Somebody told me that it needs to be at least 60 degrees pitch to allow the snow to slide off. The wife is going to measure the length and width for me tomorrow. I am getting excited to get started when I get home.


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## NaeKid (Oct 17, 2008)

I grew up in an area where snowfall would reach an average 24' in a single winter and the houses in the area were built with high-peaked roofs. The biggest thing was that all the houses had an area below the roof for the snow to settle. 

As far as the degree of the roof goes, anything greater than 45° was considered sufficient for the area and the other thing was that the roofs were metal-clad to allow for ease of automatic snow release and no eavestrough to stop the natural flow of the snow and water. Some of the houses probably had greater than 60° slope and others were built in the style of hip-roofed barns with the dual-slope to move the snow and water easily.


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