Whether you plan to build a garden shed or deck, the foundation you choose will be important.
A foundation is important because it supports the structure above and extends its lifespan by keeping it off the ground.
In our experience, many DIYers want to know about deck blocks Vs concrete footings.
So, which one is better?
In This Article– We will cover them both in detail to help you decide which one to use for your new structure.
What are concrete footings?
Concrete footings are important part of a base.
No matter if you are building a retaining wall, a deck, a shed, or a whole building, you will need footings.
Most footings are made by digging a hole put rebar in the hole, and pour the hole with concrete.
The concrete footings provide a means for supporting something above them.
For some footings, this will be a whole building, and for others, just one fence post. Concrete footings must be stable and strong, especially if the soil around the footings is weak.
Depending on the structure, many footings will be buried deep underground below the frost line.
Usually put compacted gravel at the bottom before pouring the concrete. Gravel provides drainage as well as the level.
Normally concrete is poured into a form to be stripped once the concrete is dried into that form.
What are Deck Blocks?
Deck blocks are precast foundations in simplified form.
So what is the difference? They are not directly cast in their final location.
They are specified in building codes, and they are required to follow the same criteria as a foundation.
Deck blocks need to have an acceptable bearing area- this is the area that the block covers on the ground.
They also need to be placed a minimum of 12 inches below the frost line. They cannot be placed at grade, and while deck blocks look a bit crude, they serve a purpose.
As the name suggests, deck blocks are typically are used to support deck plans. They can also be used to support is consider buildings such as sheds, etc.
Pros and Cons of concrete footings
Pros
- Because the concrete footings are site-built, there aren’t any enabled defects from the manufacturing or transportation background.
- Concrete mix ingredients are readily and conveniently found almost everywhere.
- They are great for sites that are subjected to cold winters.
- They provide great stability and support the structure.
- They are so common that construction crews have been using them for a long time.
- They support higher load levels than deck blocks.
Cons
- Concrete footings can be pricey to install.
- The installation is often time-critical.
- When the installed concrete footings sustain damage, they can be challenging to repair.
- Concrete footings require a lot of labor, and generally more than one worker.
Pros and Cons of deck blocks
Pros
- Fast install!
- No digging required.
- Comes in different sizes and shapes.
- Often can be handled by one person.
- Usually not expensive.
- Not subject to decay.
- Highly corrosion resistant.
Cons
- They can be expensive to install.
- They can have manufacturing defects or shipping damage.
- They aren’t as common.
- Sometimes they have instability considerations depending on the substrate they’ve been placed.
- They may not be made of steel.
When to use concrete footings?
Concrete footings should be used whenever:
- You are building a permanent structure that requires frost protection.
- The frost heave regulations apply: you cannot use deck blocks and need to use concrete footings instead.
- You are in a place with high uplift or high winds.
- You are building a residential structure.
- There is reason to think frost heave will occur in the soil.
- You have a heavy clay soil that retains moisture.
- You have a structure on a flood plain.
- You have a waterfront structure.
When to use deck blocks?
Deck blocks are best used for:
- Free-standing and floating structures.
- Where no below-grade concrete footings are required.
- Where location makes mixing concrete, or transporting concrete is difficult.
- Free-standing and low structures.
- Small to medium-sized decks.
Deck blocks vs concrete footings – cost differences
Deck blocks can be purchased at your local hardware store and will run between $4 each and $6 depending on your area.
They are usually an approximate size of 10- or 11-inch square, and 7 to 8 inches high. They weigh about 48 pounds each.
To put some numbers to it – if you used 9 deck blocks evenly spaced in a rectangular shape they would create a deck of 10 feet by eight feet.
That would cost you between $36 and $54.
Now if you used concrete footings to create the same material footprint, you would be looking at between $3 – $7 per square foot.
For an area of 10 x 8, which is 80 square feet that would cost you between $240 – $560.
Deck blocks are usually cheaper and they are cheaper and faster to install.
Deck blocks let you do little surface preparation and minimal digging versus footings, which also decreases your labor costs.
Clearly, we can see that deck blocks are much cheaper.
FAQs – deck blocks vs concrete footers
How should you set the deck blocks?
First, start with the corners and set each footing equal distance apart so that they all hold their load equally.
Do I have to put gravel under the deck blocks like concrete footers?
Yes. Gravel locks down deck footings and helps alleviate erosion issues that can compromise the structure.
How much weight can each deck block hold?
Deck blocks hold a minimum of 1700 PSI (pounds per square inch).
Do deck blocks sink?
Yes. Soil erosion or uneven weight distribution can sink some deck blocks. This is why you should always use more deck blocks, especially in wet conditions and loose soil.
Can you pour concrete footings directly onto the soil?
Yes, however it is often preferred for most people to put gravel down first as a base.
What type of concrete is used for deck footings?
Concrete for the footings should be structure-strength concrete. The strength of concrete should be around 5000 PSI.
Conclusion – Deck Blocks Vs Concrete Footings
When you’re constructing any structure, foundations must be taken seriously. While concrete footings are made on-site, deck blocks are precast foundations.
When determining whether deck blocks or concrete footings are your go-to, you’ll have to consider more than just ease of use and cost.
Most definitely, deck blocks are less expensive and faster to construct than concrete footings, but they should also suit specific structures and areas like a deck and low-level structures in a frost-free area.
So, If you’re building a small to medium-sized low-level freestanding deck, deck blocks might be a suitable option.
Location would need to be away from water (not on a waterfront property or flood plain), and strong winds and uplift.
Location should also be an area with soil that drains well (not clay soils) and that does not freeze.
In all other situations, concrete footings are recommended.