Shed foundation, concrete or pylon?

I’m looking at building a 12’×24’ shed, and the internet is disagreeing on whether or not I need a concrete foundation for a shed that large, or if I can just stick it on some concrete pylon blocks. Does anyone have any advice?

First check with your local city permitting offices. In the City of Plano any exterior building over 125 square feet must have a concrete foundation. Your building permit may make the decision for you.

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There was once a member who shared their contemplations on the topic of shed building…

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It all depends on the code where its built. A lot of city’s require permits & concrete foundation

Also check your city code… A shed on a foundation is a permanent structure while on skids and blocks is temporary

Where are you seeing the over 125ft² rule? Nowhere that I’ve looked has said anything about that

Which city do you live in? In Flower Mound here’s what I would have to do for a foundation for anything over 150 sqft…

“Beams must be constructed at all perimeters. All beams are required to be at least 10 inches wide and 20 inches deep with 2 #5 (5/8") bars in the top and 2 #5 (5/8") bars in the bottom of the beam. Interior beams must also be constructed and located no more than 15 feet apart. All beams must extend at least 12 inches into undisturbed soil. Place #3 (3/8") bars 18 inches on center each way in the middle of the new 4-inch slab.”

I’m looking into buying a 12’x16’ shed, so I’ve been doing my research. I’m now trying to find out how much doing the above requirements would cost. :thinking:

The 120 sf ~ 125 sf seems to be pretty standard in Texas cities. Once you exceed a certain sf a lot of other requirements come into play: exterior must match the house (so mine would have to be brick), height requirements and roofing, etc. It’ll also increase your property tax assessment and probably your property insurance.

For all intents ad purposes it like adding a stand alone garage. It sucks.

This also assumes you have no HOA block nannies with nothing better to do than harass you

I found this for Plano

FM624RY007 Residential Accessory Building Permit Requirements (English)_202003061657291806.pdf (1.2 MB)

Lake Dallas requires outlets in a shed over a certain size.

…and don’t forget any Home Owners Association (HOA) requirements, if that applies.

My HOA rules had the following written stipulation: “The following items are under the descretion of the HOA until either the housing area had been 85% built out or 20 years.” Then they listed 40+ items that they had control of. By the time I bought my property the area was already 100% built out, therefore none of the listed stipulations had any legal effect. Over the years I had to point out this clause to the HOA folks as they tried to cite me for not having 2 trees in the front yard, or having yellow flowers instead of red, etc. Each time I showed them that clause, their response was…oh, we’ll let you slide on that requirement this time. Read your HOA rules! You may be surprised at what the legallize actually says.

Lewisville demands a permit for…

  • ≥ 120ft²
  • ≥ 10’ roof peak
  • A slab
  • Electrical
  • Plumbing

My construction avoided all of the above:

  • 8x14 for a nominal 112ft² footprint
  • Frame anchored on piers
  • No utilities

Since I’m using it for ordinary household storage, I imagine that a dozen 4x4 piers with weight of the structure+contents transferred via 60-some-odd ½" bolts I’m going to be OK.

If I were going to do it again, I’d likely skip the piers and prep below-grade ‘footings’ for deck blocks.

As others have iterated, ensure that you’re within code for your city. It takes but one neighbor or an usually nosy code enforcement person that just happens to notice your project to make your life far more complicated than you wanted.

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The shed will be built in Plano. nothing on the Plano website says anything about foundations for accessory buildings. I was more asking in terms of structural necessity. Would a shed that large need a concrete foundation.

The sheet from City of Plano I posted above from their building inspectors website states you have to pull a permit for any accessory buildings larger than 120 sqft in Plano. You also have to arrange for inspections and submit architectural renderings if the shed is not a prebuilt. Since they include a drawing with the requirements for a concrete foundation in the sheet it might be wise to assume that is what they want. So you might as well contact The City of Plano Inspectors to see what is required before going too far with any planning.

Building Inspections Department ~ 1520 K Ave, Suite 140 Plano, TX 75074 ~ 972-941-7140 fax 972-941-7187 www.buildinginspections.org ~ email address ~ [email protected]

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Suggest you call the City of Plano’s Permit Office and ask your specific question. Then follow up on this thread with the offical answer. Seems like many DMS folks need the same answer.

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Plano resident that just had a shed built.

Plano’s regulations are it must be 120sqft or less. Anything above that requires a building permit. Must be at least 10ft from the house and 3ft from the fence/property line. Can only be 10ft tall unless you have a full 10ft clearance around the building.

There are no specific instructions for the pad but I’m not sure what’s recommended if you go over 120sqft as I didn’t. A pad is always going to be your best bet, especially on larger buildings, but that definitely jacks of the price and logistics. My 8x14 is just sitting on blocks but the entire base is framed metal

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I’m not asking about permits here. I’m asking about structural necessity.

What are you using the shed for? What kind of mass are you expecting this structure to support and what kind of loads will you be putting it under?

If it’s a typical storage shed or workshop, modest over-engineering of a pile foundation will suffice. If you’re going to be running a power hammer then you’ll need a reinforced slab and considerable dampening of the tool itself.

If your use for a 12x24 shed is more pedestrian - ala storage shed or small workshop - I’d opt for a pier foundation. I’d plan for at least one mid-span pier across the width since 8’ quality lumber is easier to source than 12’ and unless you want a lot of 2’ cutoffs 4’ spans make for even more redundancy. A lot less effort (probably) to do site prep for deck blocks than actual sunk piers, making it easier to overprovision piers to shoulder load and reduce loading on the frame; note that you will still need to individually prepare and level each deck block. With more of the weight of the building being transmitted at the perimeter I’d overprovision that area.

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The house I live in was only recently annexed into the city limits, so I have had quite a bit of freedom in overall designs.

To that, I have a barn that is built on peers that is 30x60, with a dirt floor. The house is also built as peer and beam, so I don’t think the actual square footage is your controlling factor (design wise), but rather building codes and their requirements (city or HOA, etc)

At the end of the day, building a complete house, and building a workshop or shed, your building the same “type” of structure. Now, before I get flamed here, yes, there are differences, but your basic design of 4 walls (give or take) and a roof is still the same.