I have a porch roof that the previous homeowner did half arsed, 4 pillars set in concrete (link fence posts). Now one side is sagging badly. My brilliant idea is to to replace the 2x4 (4) with 2x6. I have already gotten the post pillars to support the structure. So here is my issue. Would it be best to auger out a large hole and make a concrete pier rather than to just just pour concrete and set the posts? I have heard old timers talk about using gravel at the bottom to help keep the post from sinking but I am wanting something a little more sturdy

  • Sagging would be caused by a poor foundation , nothing to do with 2 X 4 s.'. I have a 13' X 13' addition supported by 2 X 4 s , some on 36" centers and one 72 " span ( 25 years old). Jan 26 '20 at 16:47
  • I agree with blacksmith. A 4x4 is strong enough for many porches my rear porch has 4 x 4’s , the number is based on the width. The 2x 4, 6 or 8 is based on the length and roof type / climate zone. The depth of the pier and the size is the the problem here, my 1930 house is sitting on pre made pier blocks, they are below the top soil and 4x4 to the main beams. Yes they are only spaced 4’ apart but this is holding up the house (originally sitting on rocks)
    – Ed Beal
    Jan 28 '20 at 18:32

Gravel will not do you any justice. It is just a cheap way to go deep in ground to get to good bearing soil if it needs to go really deep. Pole barns, for example, are built with 6X6s set in the concrete 4' deep, for a porch roof if it is small enough it won't need 6X6s but 4X4s will suffice if the roof is not too high.


If it has a roof, build it on a solid foundation: piers, slab, etc.

Save the poles-in-holes business for fences and gates.

  • Those posts are fine no reason not to use them.
    – Ed Beal
    Jan 28 '20 at 18:34

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