building carport need help

   / building carport need help #1  

fairwelder

New member
Joined
Feb 8, 2012
Messages
3
Location
texas
I currently have a 20 X 20 carport. I would like to build a 3 car carport with no braces in the middle. My corner posts will be 4'' pipe. What size c perlin or square tubing accrooss the top do I need to use. I DO NOT want it to sag. Please help.
 
   / building carport need help #2  
Not enough information. What you want to do is build some trusses, but you didn't say how far you want them to go. I've only worked with wood, so I can't help you here. Try doing a search on google for metal truss designes in the length you need.

Once you have the design, you need to deside on the spacing based on the size of your purlins. Are you putting on a metal roof?

4 inch pipe should be strong enough to support the load, especially in Texas, but it will have to be braced and you will need a beam, or header to hold up the roof between the posts. Or you can put a post under each truss and carry the load straight down to the ground, which would be ideal.

Eddie
 
   / building carport need help
  • Thread Starter
#3  
First off thanks eddie for the response. The carport will be 20 X 30. 30 foot span is what concerns me. Thanks
 
   / building carport need help #4  
May be too far for you (about 3 hrs) but check with J&I Mfg in Madill Oklahoma. I bought prebuilt steel trusses for my 30x36 carport from them as well as the steel purlins. There trusses are enginered and they will tell you how far apart to put the trusses and the purlins ... My trusses are 12' o.c. and I think my purlins are 4'0" o.c.
 
   / building carport need help #5  
30' is a piece of cake for steel truss without snow load. :thumbsup:

the only thing you need to decide is what depth is acceptable.

the less depth, the stronger materials required... the truss manufacturers will know that stuff, or should be available online.

you may also need to knee brace the posts if you are only going with one on each end.
 
   / building carport need help #6  
I currently have a 20 X 20 carport. I would like to build a 3 car carport with no braces in the middle. My corner posts will be 4'' pipe. What size c perlin or square tubing accrooss the top do I need to use. I DO NOT want it to sag. Please help.

My 20x36 ft carport frame (9 ft walls) is built from 14 ga 2-1/4 x 2-1/4 inch steel tubing.

Carport install-1.JPG

Don't know what's the size of the C purlins. You can estimate it from this photo.

Carport install-2.JPG

In this county this type of carport has to be engineered. It's designed for 90 mph wind, 2 psf roof dead load, 30 psf roof live load, ground snow load 30 psf, seismic category D.

Good luck.
 
   / building carport need help #7  
I currently have a 20 X 20 carport. I would like to build a 3 car carport with no braces in the middle. My corner posts will be 4'' pipe. What size c perlin or square tubing accrooss the top do I need to use. I DO NOT want it to sag. Please help.

10" C purlins will work on five foot centers maximum. I would go four so that you can walk up there comfortably.

You can buy car port trim that will make it look great.
 
   / building carport need help #8  
My 20x36 ft carport frame (9 ft walls) is built from 14 ga 2-1/4 x 2-1/4 inch steel tubing.

View attachment 250660

Don't know what's the size of the C purlins. You can estimate it from this photo.

View attachment 250661

In this county this type of carport has to be engineered. It's designed for 90 mph wind, 2 psf roof dead load, 30 psf roof live load, ground snow load 30 psf, seismic category D.

Good luck.

Just curious, once those boys got that end panel done. Was the rest of the roof installed from the ground?
 
   / building carport need help #9  
Just curious, once those boys got that end panel done. Was the rest of the roof installed from the ground?

Carport install-3.JPGCarport install-4.JPG

Yes and no.

Hope you're shoulder is on the mend:thumbsup:
 
   / building carport need help #10  
View attachment 250783View attachment 250784

Yes and no.

Hope you're shoulder is on the mend:thumbsup:


Shoulder's killing me. Physical therapist decided to show me who is boss. First visit was a farce in my opinion. Today when he realized I had more range of motion I guess than he thought was normal he sent in the helper from hades and proceeded to have me doing exercises. Some of them I can do on my own at home. He told me to try to do them twice a day. I asked if I could do them three or four times a day. We'll show them if it kills us.

On the carport. I would box it using ten or twelve inch c purlins with cross pieces on four foot centers. You could get away with five but I would go fours. If there is no snow load issues I would go with a foot and a half pitch front to back twenty feet. I would go with the carport trim kits which make it look professionally installed and I would use the gutter too.

The biggest problem with a thirty foot span on a purlin is twist. I would lay down two rows of X's to eliminate that. I would put a strap, angle iron, pipe, tubing, solid rod, whatever, from the top of one purlin to the bottom of the one next to it. I would put another strap that is opposite of the first. You could get away with one set of X's but I would put in two.

This will be appreciated when it comes to installing the roofing sheets, especially when you get to the middle and the twist can be quite unnerving.

Probably the biggest mistake made by newbies is not getting the framework as square as possible. An inch here becomes a foot by the time it gets to there. Put down your first end sheet, get onto the roof, measure at each end for the edge of the second sheet, screw it down. But measure every sheet. And be sure you use the double sided sticky tape between sheets. Pull one side off and put it down on the previous sheet. Place the next sheet, put in a couple of screws, lift up the next sheet and pull the other side of the sticky tape, screw it down.
 

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