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Deck Posts set directly onto dirt

I just moved into a place with a small new deck whose posts are set directly onto the dirt. I'd like to enclose the bottom of the deck to use for storage, but want to first shore up the posts. The wood is pressure treated, but set that way, directly onto the dirt seems sketchy. Do I just need to try and dig holes and install new posts? Is there some way of getting some metal or something around the existing ones? 

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Posted 2016-04-18T23:38:39+0000  by lukewiget lukewiget

Hello lukewiget and welcome to the Community.

I would check with your local municipality to find what building codes are in your area.  And with local contractors to determine if this is a common practice in your area.


In my experience deck post are mounted above ground using a standoff metal post base and the concrete acts as a pier to connect the post to.  Here is a project guide for setting posts on a pier.


Your beams, joist and the rest of the deck parts are directly tied to the post.  Here is a project guide for building a raised deck.


There are different ways of installing the beams to the post. One way is to mount the beams on top of the post, another is to box in the post with your beams and the third way is to sandwich the post on opposite sides and secure with through bolts.  Depending on the method of construction, there may be some way of shoring up the deck platform and installing new post assemblies.  Without more details it would be hard to say.


Again, I would ask an experienced contractor is they would have a suggestion after viewing your situation.


If the deck is sound at this time, you may want to live with it as is, until your post start deteriorating.  Don't wait until your situation may be dangerous.  At which point you may need to deconstruct your deck and install new post properly.


Thank you for your inquiry.



Posted 2016-04-19T19:11:21+0000  by Char_HD_CHI
Hi lukewidget,

Decks are not solid cover for storing anything that will mold or mildew.

Their slatted decking boards are intentionally spaced to allow water to pass.

And, even when you install a water collection system beneath the flooring, keeping the area open to air flow is needed to prevent evaporation from building up inside the closure and destroying whatever you store there.

If you close this area, make certain to add active, motorized vents to draw air through and evaporate collecting moisture.

The only permanent way to prevent moisture from collecting would be to install a floor and walls, insulate, and install air conditioning and heating in that space.

Every structure built over soil is susceptible to erosion of the surface upon which it is built.

That is one reason that almost every code jurisdiction requires footers be installed below the "frost line."

You should check local codes, as Char suggests, and expect to find a requirement for footers.

Do not waste your resources by attempting to store degradable goods or tools in this space unless you're willing to ensure the area will remain constantly dry.

Invest your time and money toward making your deck safe by building footers to support the structure and bring it up to local code.

Because you've stated your intent to create storage space, I'd recommend looking for other areas within the heated and cooled space of your dwelling which would be more suitable for your purpose.

Hope this helps,

Pat InPaint

Posted 2016-04-20T19:49:14+0000  by Pat_HD_ATL
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