As we gear up for warmer weather and summer festivities, many of us are considering building, upgrading, and redesigning outdoor living spaces. One of the hottest tickets this time of year is a new outdoor deck, increasing and maximizing outdoor living space for entertaining and family enjoyment.
There are many considerations in designing a new or updated deck, but one of the biggest and most important is the deck’s footing and foundation.
What To Consider When Choosing A Deck Footing
A strong foundation is essential to the durability of any structure, and decking is certainly not excluded from this rule. Without such, the deck is liable to shift, move, and even collapse. But there are many factors to consider when choosing a footing or foundation material and style.
- What is the slope of the property? The slope of the property determines how much hold a foundation must give. For instance, a steep slope will require stronger footing on where posts are taller.
- How high from the ground is the deck? If the deck will be positioned off the second floor, or even on a side of the house that’s further off the ground, there will be more space between the footing and the decking surface, increasing the stability required for the foundation.
- How large will the deck be? Even if the deck is mere inches off the ground, a large deck will require a sturdier foundation than a small one, namely because it will likely carry more weight and have more space between posts.
- Will the deck be attached to the home or another permanent structure? Whether the deck is attached or floating is a big determining factor in what kind of footing and foundation is required. When the deck is attached to a home it benefits from the strong foundation the home itself already has.
- What do you plan to house on the deck? When planning a footing or foundation material for the deck, it’s important to consider what will likely sit on the deck. If you wish to install a heavy bar or hot tub, consider using the strongest foundation or footing you can install.
- What kind of soil surrounds the deck? If you live in, for instance, a beachy area, you might be plagued by soft, sandy ground. But if you live in the mountains, you may be forced to contend with rocky soil. The kind of soil surrounding the deck determines how supported it is, and absolutely informs the style of deck footing required.
What Are Your Deck Footing Options?
When choosing a footing for the deck, you have some flexibility based on the above considerations. For some extra help in choosing the right foundation for your deck, continue reading for a comprehensive list of footing options and the cost, benefits, and drawbacks of each.
1. Buried Post Footing
Buried post footing involves digging below the frost line and pouring a small concrete base, then inserting the deck post while the concrete is wet, followed by letting it dry and building up the deck. Often, but not always, a post wrap is installed around each deck post to protect the wood from moisture in the ground.
The buried post method requires a moderate cost of labor if you aren’t comfortable completing the project alone, but it’s a great option if a little extra security is required of the deck’s foundation.
A buried post footing is best for decks that require moderate to high levels of support. A buried post doesn’t require a lot of concrete or very much labor, but it does add that little bit of extra concrete support required of larger sized decks or decks that will bear a heavy load. Buried post footings can also be a helpful solution to soft soil.
The material cost of a buried post foundation is minimal, as the only real material used beyond the deck itself is a few buckets of concrete totaling $40-$150 depending on the number of posts. If you require professional installation help, you can increase the price to about $150 per post.
- Added stability with minimal cost
- Enhances footing in soft soil
- Low cost of materials
Keep in mind:
- Usually requires a professional for installation
- Added installation time of allowing concrete to dry
- Cannot be moved as the foundation is permanent
2. Poured Concrete Footing
A poured concrete footing is going to be your strongest, most permanent and stable deck footing. While similar to a buried post footing in that it involves pouring concrete to below the frost line, a poured concrete footing includes additional fortification by metal brackets. Once the concrete is poured, a bracket is used to affix the deck post to the concrete pillar, forming a virtually indestructible deck footing.
A poured concrete footing is best for decks that require several layers of fortification due to a combination of the following factors: heavy components like outdoor bar areas and hot tubs, extra-large deck size, second story decking, soft soil, and steep property slope.
While this is the strongest deck footing style, it’s also the costliest. It’s not recommended to try to DIY this deck foundation, since if your deck checks some of the boxes that require a poured concrete footing, you already know you have extenuating circumstances that prohibit mistakes. Material and labor all together, this style of foundation costs close to $500 per post.
- The most durable footing style
- Can bear unlimited weight
Keep in mind:
- Must be installed by a professional
- Requires a rather large decking budget
- Cannot be modified once installed
3. Deck Block Footing
Deck block footings will perk your ears if you’re a DIY-er, because everything required for installation can be bought prefabricated from most hardware stores. Fabricated cement deck blocks are buried just below the surface of the ground and deck posts slide right into pre-notched tops for easy installation.
While this is the easiest deck footing to install, and the skill level is considered “beginner”, it is recommended only for small, low-to-the-ground decks that won’t bear much of a load. Deck block footing is also versatile and can be moved and relocated to accommodate changes if you plan to update or reposition the deck in the future.
Not only is this one of the easiest deck footers to install, it’s also one of the least cost prohibitive. At about $10-$25 per post, this deck is affordable for any budget.
- Can be relocated and adjusted in the future
- Quick, easy installation
- Will not permanently damage the soil or ground
Keep in mind:
- Will not bear heavy loads
- May require more posts than other styles of foundation
- For use only in hard soil
4. Screw Pile Footing
Screw pile footings inhabit the best of both worlds: quick installation and lasting durability. Because this footing consists of steel screws installed to below the frost line, they are just about as durable as a poured footing but without the drying time required of cement. They can accommodate any size deck and can bear any weight.
Screw pile footings are best for high-budget decking projects that require substantial foundational security. Because the screws must be installed using professional machinery, there’s a good bit of labor cost involved, but the result is an immediate, strong decking foundation.
The cost per post for a screw pile foundation is roughly $200-$300, depending on location and depth of the frost line.
- No drying time, unlike concrete
- No labor expended as this requires professional equipment
- Heavy load bearing, indestructible foundation
- No real disruption to the soil
Keep in mind:
- Can only be completed with professional equipment
- Cost prohibitive
- Best for medium to hard soil
5. Cement Block Footing
A cement block deck footing is similar to a deck block footing in many ways, but it’s a little less expensive and even easier to install. Whereas deck block footings use buried, precast deck blocks, this footing utilizes basic cement blocks with appropriate openings to accommodate a deck post. Placed on top of the ground, the cement block can hold a post for a small deck.
While this style of footing is easy to install, it’s not exactly the most formidable option. It won’t be the safest choice for tall, large decks that will hold heavy furniture, but it’s suitable for small decks that aren’t far off the ground (especially floating decks on flat graded soil).
Literally anyone can DIY this footing given the right circumstances, so the labor cost associated with a cement block footing is $0. The cement blocks can range from $1 to $10, making this the most affordable footing option.
- Easy installation, no experience required
- Can be adjusted as necessary
Keep in mind:
- Not for large or heavy decks
- Only for use in decks that sit close to the ground
- Best on level ground
6. Gravel Post Footing
Gravel post deck footing combines two of the most popular deck foundations: poured concrete and buried post. A buried post foundation consists of a slim tube of concrete poured beneath the frost line with a post inserted, and a poured concrete foundation utilizes a large-sized column of concrete with a post fastened to the top.
But a pier and footing foundation uses a disc-shaped concrete base poured into a wide hole, beneath the frost line, with the post inserted into the concrete and covered by gravel. It requires fewer tools than a poured foundation and has a little more hold than a buried post.
Gravel post deck footing is best suited for medium-weight and mid-sized decks. The deck can sit further from the ground than with many other footing methods, but it’s not recommended to put heavy furniture like a hot tub or outdoor bar on the deck if you choose this footing method.
The cost for this footing rests largely on the labor used. While the materials themselves are only about $50 per post, if you hire a professional each post can cost coser to $250 to construct.
- Simple, low cost installation
- Can carry tall decks on a steep slope
- Possible to DIY if you have some experience with concrete and know the frost line
- The gravel in the post hole helps drain water in humid climates
Keep in mind:
- If you don’t have experience with concrete, it’s best to call a professional
- Not intended for ultra-weight decks
- Hole for concrete must be dug below the frost line