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I'm starting a project to turn my covered porch deck into a covered stamped concrete patio. The 3 support posts for the roof all need replaced.

There is a 4th post that needs replaced as well that is not load bearing but might be utilized as such due to its location and connection to a crossbeam. Basically, the previous homeowner had an unnecessary support crossbeam added mid-roof. This 4th post is connected to the crossbeam.

Due to the roofs small size and placement of the crossbeam, I believe that this one post could temporarily support the entire roof. All 4 posts were set in concrete below the ground.

I'm looking for the best option to set the new posts when replacing them.

My thought would be to have the patio concrete set then install the posts on top vs set the new posts in ground and lay concrete around them.

If that's the case, how do I support the roof while the concrete work is completed?

If it's better to replace the posts and pour around them, what is best way to set them so that the concrete looks uniform?

porch roof showing posts and roof construction

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  • What is the size and spacing are the roof joists? (Maybe you could eliminate the mid-span beam supporting the joists.) where are you located so we know if you have a high snow load.
    – Lee Sam
    Apr 6 at 19:39
  • Ok that mid span is almost funny the bottom of the post are not visible, they don’t look that old or weathered are they sitting in water? Place posts supports on the concrete pillars and pour the ones I am thinking of have a 3 or 4” pipe between the bottom and the post sleve Where you can nail to
    – Ed Beal
    Apr 6 at 19:49
  • @LeeSam, I'd have to measure the joists in the morning but the roof is well built and was just replaced 1.5 year ago. I'm in Southern Delaware, so snow load is something contractors here don't know much about. Apr 7 at 0:42
  • @EdBeal, up close they are weathered and splitting, with some minor warping. They might be good for a while to hold, but I'd rather take care of it before it becomes an issue. Since I'm taking the deck out, I figured now is as good a time as any. The mid span is warped at that end but is secured in a bracket. I looked at having the deck replaced in the past year and several contractors said that it could come out without issue. Apr 7 at 0:48
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    "My thought would be to have the patio concrete set then install the posts on top" Yes, do this. Get galvanized steel post bases and have the anchor portion embedded in the concrete as it's poured. Once the concrete has cured enough to work on it, you put the posts in the other part of the base and bolt the two base pieces together.
    – FreeMan
    Apr 7 at 13:27

2 Answers 2

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No, that interior beam cannot be used alone. The cantilever would be more than twice the initial span, putting huge force on both the comically undersized beam and the roof attachment. I'd do this instead (and have done many times):

  1. Screw a 2x6 to the underside of the rafter tails, out at the end.
  2. Install 3 or 4 temporary posts at a slight outward angle down to support blocks slightly embedded in the soil and/or staked well. These could simply be doubled 2x4s in a T configuration. Leave about least a foot from where your concrete forms will be set for working clearance, but keep the tilt minimal.
  3. Remove all existing posts and beams and build your patio.

Tips:

  • Temporary posts must be securely anchored at the top and bottom. The fact that they'll be tilted means that there will be some lateral load. Use long screws and support cleats.
  • When you install the temporary posts, lift the roof slightly above its final height. This will make installing the new support structure much easier.
  • Use carpenter's lines and long levels to build the new structure. Do not rely on the current or future position of the rafters.
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It appears to me that you could temporarily add to/lengthen the existing rafters and add temporary posts and support the entire structure from the ground outside of the porch area while the work is being done. The same thing could be done with the 4th post if need be.

It looks like the 4th post is moot, and perhaps added at the previous owners request for some other reason. I don't think it's needed.

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  • This is a good idea if more clearance is needed below than what my plan provides. Four 2x6 extensions could be screwed to the rafters and posts installed. They'd carry just fine.
    – isherwood
    Apr 7 at 13:33

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