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Home Inspector: Are Diamond Pier footings approved in your city?

Diamond Pier Footing Approved

Last week I posted an update on Diamond Pier footings, and since then I've had a number of people ask me whether or not Diamond Pier footings are approved for use in this city or that city. The best way to get the most accurate, up-to-date answer to that question is to contact the building inspections department for the specific city and ask.

Why can't this information be quickly looked up? Because the Minnesota State Building Code does not specifically allow the use of Diamond Pier footings. There are a bazillion products that the building code doesn't specifically allow. That doesn't mean they can't be used, but the building official needs to give permission to use them. That's why plans need to be submitted to the building official before work is started. Section 1300.0110, Subpart 13 of the Minnesota State Building Code says:

Subp. 13.  Alternative materials, design, and methods of construction and equipment.

The code is not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by the code, provided that any alternative has been approved. An alternative material, design, or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the code, and that the material, method, or work offered is, for the purpose intended, at least the equivalent of that prescribed in the code in quality, strength, effectiveness, fire resistance, durability, and safety. The details of any action granting approval of an alternate shall be recorded and entered in the files of the Department of Building Safety.

So, do Diamond Pier footings comply with the intent of the code? Are they at least the equivalent of that prescribed by the code in quality, strength, effectiveness, etc? For a manufacturer to prove that their product meets the intent of the building code, they get an ICC-ES report. It's a report designed for building code officials to use to help determine if a product meets code, and it tell the building code official exactly how a product is supposed to be installed. In fact, the instructions in the ICC-ES report actually supersede the manufacturer's installation instructions. If you're building a deck, a few components on the deck that may need an ICC-ES report are the composite deck boards, the aluminum guardrails, the structural wood screws used to fasten the ledgerboard to the house, the joist hangers, and the lateral load connectors. Diamond Pier footings have an ICC-ES report too, which can be viewed here: ESR-1895.

As long as the building official determines that Diamond Piers meet the intent of the code, they shall approve their use. So, getting back to the question at hand: are Diamond Pier footings allowed for decks in <insert city>? I called the building inspections departments at the twenty largest cities in Minnesota to find out. Here's what they said:

Apple Valley yes
Blaine yes
Bloomington yes
Brooklyn Park no
Burnsville yes
Coon Rapids yes
Duluth no, because "they have not been state approved".
Eagan yes
Eden Prairie yes, need to use DP75 footings
Edina yes
Golden Valley* yes… but they require a test hole to be dug first, as well as a site inspection.
Lakeville yes
Mankato yes
Maple Grove yes
Minneapolis yes
Minnetonka yes
New Hope* yes
Plymouth yes
Rochester yes, case by case basis
Saint Paul yes
St. Cloud yes
St. Louis Park no
Woodbury yes
* Not one of the 20 largest cities, but included in this list anyways.

So there you have it. Of course, by the time you read this, the answers might change. If you have any specific questions about the answers given, contact the building inspections department at that city.

For more information on code approval of Diamond Pier footings in Minnesota, check out Diamond Pier's discussion of this topic on their web site: Code Compliance Information for Diamond Pier® Foundations in the State of Minnesota.

Post update 5/21/15: I received an email from a reader last night asking for a link to an independent study or data showing how this product works and performs.  I've posted all of these links already, but perhaps it would be helpful to have them all in one place.  Here they are:

Author: Reuben SaltzmanStructure Tech Home Inspections

          

Home Inspector: Diamond Pier footings make decks easier to build

It has already been two years since I first blogged about Diamond Pier® Foundation Systems. Where does the time go? In my original post on Diamond Piers back in 2013, I talked about how my neighbors were having a deck constructed with Diamond Piers, and I said I'd try to revisit this topic each year to track the performance of their deck.

I completely forgot about that until I re-read the original post just recently, because I'm probably going to have a deck added onto my own house this year, and I intend to have Diamond Piers used for the footings instead of traditional concrete footings.

In short, Diamond Pier footings are a pin foundation system. A Diamond Pier is a chunk of concrete with four holes in it, through which long steel pins are driven into the ground. They're far faster and easier to install than traditional concrete footings, and they're more resistant to frost heave than traditional footings. The short video clip below shows how they work:

Last winter was a pretty bad year for frost heave.  It got really cold and there was very little snow cover to act like insulation, which caused a lot of decks and porches to heave. So how'd my neighbor's deck hold up? Perfectly.

Rear view of deck

Side view of deck

Diamond Pier at patio

Diamond Pier exposed

Surprisingly, there doesn't seem to be a whole lot of decks being built in Minnesota using Diamond Piers. I don't have any statistics, but just based on my experience, these things haven't even put a dent in the market, despite gaining approval from most building inspections departments.  My best guess is that people aren't aware of the product, or they assume Diamond Piers are more expensive, but they're not.

According to the guys at All Around, the average installed price for a traditional 18" concrete footing is the same as the installed price for Diamond Pier's DP-50, which is the equivalent of an 18" footing.

Diamond Piers are superior in performance and they're far faster and easier to install. They cost more than a traditional concrete footing, but the installed cost is the same when factoring in the price of labor. So why aren't more folks using them? I have to assume they just don't know about them. Click this link for a list of lumber centers throughout Minnesota that sell Diamond Piers. Next week I'll have a follow-up post discussing code approval of Diamond Piers in Minnesota.

Post update 5/21/15: I received an email from a reader last night asking for a link to an independent study or data showing how this product works and performs.  I've posted all of these links already, but perhaps it would be helpful to have them all in one place.  Here they are:

Author: Reuben SaltzmanStructure Tech Home Inspections

          

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