Is your deck foundation safe?

In the fourth and final part of our safety blog we’re discussing the foundation of your deck. Deck foundations can be a weak point in deck designs. There is much contention in Michigan over the best way to design the post footer connections. In the picture below we have an example of posts being exposed to ground contact. This is the most ineffective way to design a footer system. In Michigan where our soil freezes 4 months out of the year and is a sponge the other 8 months, 4x6 and 6x6 pressure treated ground contact posts come in direct contact with soil and In most cases posts are buried 42 inches in the ground and set on a concrete or composite footers. The ground soil content, moisture content, and temperature will determine how long those posts will last. Some will deteriorate faster than others.

Ground Contact Posts

Here is an example of a commonly used style of post foundation in West Michigan. There is a danger of ground contact damaging your connection point with the post bottoms so close to grade.

Composite Footer

By far this is the most common practice in West Michigan. It will pass codes and is safe for some years. But there are better ways.

Deck Footers

We highly recommend a Pier and Footing system for our climate.

These are four examples of popular post connection methods commonly used in our region. The first is a sono-tube not attached to a footer. This will allow your deck to sink if the soil is over saturated or a lot of freezing and thawing were to occur. The second is a bell pier system, this is effective but over kill and expensive. The third is the weakest possible connection system. The wood is in direct contact with the soil, and the pressure treated wood is in direct contact with concrete (a chemical reaction due to the copper content in pressurized wood will occur when in direct contact with concrete) If you want your deck foundation to last and your deck to be safe the fourth picture is a great choice. It provides a footer that a poured post of concrete can sit on so no sinking, the footer concrete is cured with re-rod protruding from it to tie the concrete post to the footer. It brings the concrete above the grade so your post is not in contact with soil. And if you were to add an approved metal connection it will keep your post away from concrete contact.

Sonotube makes the pier system easy!

This process is actually quite easy just time consuming and expensive. It can cost around 250 dollars per hole. You will need to weigh the expense against the benefits and decide.

Pier Systems

A pier system can eliminate ground contact to wood, it can provide stronger support, and stand up to frost heave. This is the best alternative to post in the ground systems currently accepted nation wide.

The Michigan MRC was last updated in 2015. While much contention over why; has lawmakers arguing, the fact is it will be updated eventually. Outdated systems of footer to post connections, and burying wooden posts will be a thing of the past as soon as they do update the codes. Every state and country that border Michigan require pier systems that allow for greater frost heavy, and eliminating natural products from the ground contact.

Helical Piers

These helical pier systems are the newest ways to provide support while keeping your post connections out of the ground. This process is easy and less messy than digging hole. It can be costly. Be sure to take the documentation from the company providing the pier system to the township office. Your local inspector will most likely require manufacturer specs before passing this system.

We, at Divergent Deck Builders, want to help you build the most maintenance free outdoor living space possible. This includes the footer to post connections. The crucial concern is bringing natural products like timber out of ground and providing a material such as composite or concrete for ground contact footers.

Helical Pier Ground Level Deck

Helical pier systems can eliminate the need for concern over moister or soil effecting your beam and posts. Here is an example of a great application for this system.

Decks represent a significant upfront investment. If we don't pay attention, it's easy to choose materials or make choices that will mean ongoing maintenance and frequent repairs.

What Next?

If you’re in the market for a brand-new deck, let’s talk!

At Divergent Deck Builders, we build composite decks for clients across West Michigan. We work with each customer to design and build their dream deck while meeting all the codes and requirements. Feel free to check out some of our Most Recent Builds.

If you’re ready to get started, request a FREE DESIGN SESSION, and we’ll provide you with a custom quote based on your specific project.

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