Extra base or concrete footer for structural columns on patio?

Discussion in 'Hardscaping' started by mcclureandson, Aug 9, 2008.

  1. mcclureandson

    mcclureandson LawnSite Member
    Messages: 242

    We're installing a 16'x25' herringbone pattern patio that will be underneath the line of a newly (to be) constructed porch/addition. It'll be about a 9ft ceiling height and plans call for 8, 12-inch decorative columns...overkill for the load but relative for the design. These columns will set on our finished patio...which we'll complete prior to their installation.

    My question is what precautions do I need to provide in addition to our regular compacted patio base? My first thought is a standard concrete footer for each column...then our compacted base, bedding sand and pavers...but would it be sufficient to COMPACT a 12" footer from our usual base material?

  2. PaperCutter

    PaperCutter LawnSite Bronze Member
    Messages: 1,996

    What did the permit office agree to?
  3. DVS Hardscaper

    DVS Hardscaper LawnSite Fanatic
    Messages: 6,622

    whatever the building code calls for.

    However, if it's structural I'd assume the columns have to be planted at LEAST 24" in the ground. With concrete. This is what prevents SWAY.

    When columns are resting over the surface of the ground - SWAY will be more prevelant.
  4. mcclureandson

    mcclureandson LawnSite Member
    Messages: 242

    I don't know if I gave enough information in the original post...columns will support the roof over the patio - not an enclosed porch or addition overhead. The columns are sitting ON the finished patio - and a single 12" footer beneath each column is all that's spec'd. I was curious (since I sell our driveway/patios as superior to poured concrete with regards to cracking/settling) why a compacted 'footer' wouldn't be superior as well?
  5. jaybird24

    jaybird24 LawnSite Senior Member
    from midwest
    Messages: 623

    I'm assuming the roof is free standing somewhat like a pergola. We have always installed these on 4' deep concrete piers to meet code here. The columns then get built around the 4x4 or 6x6 posts. I would think using the columns as the main load bearing structure will cause problems down the road. If we use 4x4 posts we usually wrap them with more decorative wood facing for a more balanced look with the columns. If you are going to build on top of the columns I would put them on a concrete footing, compact the base really well, then use 6x6's to box and level the footing pad and build off that. Almost all columns we have built end up with a 4"x4" hollow center that fits a post real well, so it would have to be built on top of a cap, so you would need a pretty stout and structurally sound cap to make it work as well.
  6. Blk94fiveOh

    Blk94fiveOh LawnSite Member
    from MN
    Messages: 112

    The standard depth aggregate will still flex with the "footer" aggregate regardless of how far you go down in those certain area. I would play it safe, and use a concrete footer.
  7. mcclureandson

    mcclureandson LawnSite Member
    Messages: 242

    That's what I was wondering...thanks.

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