Need to replace porch columns

[Carroll B]

The roof on my front porch comes out from the house 6 feet. The roof is supported by 6 wooden 4x4 columns. The columns are 94 inches tall. The top of the columns support what looks to be a double 2x8 header that is wrapped in aluminum. One of the columns has a small rotten place at the base. I would like to replace all the columns and railing with PVC columns that have a metal pole in the center and they are rated to support 3000 pounds each. My question is can a person with average skills replace the columns? I've installed bathrooms, built sheds, and installed porch railings in the past, installed doors, but never something that supports a section of roof. I assume I would need to jack the roof up 1/8 of an inch to install the new columns and could this be done using a pressure treated 4x4 and a hydraulic bottle jack? I am not sure if the current columns are toe-nailed to the header. The current wooden columns are sitting on metal standoffs that sit on the concrete porch. If the new PVC columns need to be attached to the header how would I do this or is the weight of the roof enough to keep them in place? Should I play it safe and hire a contractor to install the new PVC columns and then I install the new PVC railing?

 

[lakelandcat]

If your porch has a solid foundation replacing your pillars is no problem with a bottle jack and 4x4 support. just do one at a time, distribute the weight with a 2x6, if all you want to do is repair your existing column you can carve out the the bad section until you hit good wood and use something like ready patch. Make sure your bad area does not compromise your support column.

 

[Jlbc212]

A bottle jack with a 4x4 will certainly work, but I've found it easier to just cut a 2x4 a bit longer than the height distance and wedge it between the header and the base. If you plan on leaving the temporary 2x4 in place for awhile you can double it up. Use 2-1/2" torx head deck fastening screws to double up the 2x4's.

 

[6768rogues]

When I did that stuff for a living, I always had a cheap spare adjustable height jack post around. When replacing porch posts, I put the jack post in the truck and used it. It didn't cost much, it is safe, it is easy to use, and I have used the same one dozens of times. Set it up with the screw on top, give it a few turns, and your old post will come out.