Steel reinforcements have been used in concrete for over a century. Originally it was just twisted square bars, but the intent and function were similar. Around the 1940s, things began to evolve toward the rebar we know today.
Some older styles still meet modern standards for support, but not every cement construction needs rebar. Does a pool deck need rebar?
The minimum depth for cement to use rebar inside is five inches because concrete has weak tensile strength despite its compression capabilities, and rebar helps that. Since pool decks have an average minimum depth for cement of four inches or deeper, rebar should be used for added reinforcement. Adding rebar will extend the working life of the pool deck.
Why Does A Pool Deck Need Rebar
Pool decks need rebar when the cement is sufficiently deep to require reinforcement. Cement has been used since Joseph Aspdin invented it in 1824 by burning fine powdered clay, limestone, and chalk until the carbon dioxide was gone.
The resulting blend, when mixed with water, formed, and dried, gives a potent stone-like result that has incredible compressive strength. That’s why cement goes under buildings and can hold them up.
The strongest modern cement, according to cement.com, is “Ultra-High Performance Concrete (UHPC) is a cementitious, concrete material that has a minimum specified compressive strength of 17,000 pounds per square inch (120 MPa) with specified durability, tensile ductility, and toughness requirements…”
While that’s great for holding things on top of a slab, the downfall of cement is that it has zero flexibility. Adding rebar helps prevent the cement from flexing by adding stability and rigidity on the horizontal plane.
In short, it prevents cracking. So, if you have deeper layers of cement, and you don’t want a cracked and broken pool deck, you’ll likely need rebar.
How Much Rebar Is Needed For A Pool Deck
The amount of rebar you need for your pool deck depends on the dimensions of the deck. I have done some of the basic math for you on the chart below, assuming your deck is five or six inches deep.
Feel free to bookmark this page if you want a good reference.
Rebar Calculations for Square or Rectangular Pool Deck Space
|Length||Width||Bar Spacing||Edge Clearance||Total # of Bars & Size(s)|
|8′||8′||18″ x 18″||3 Inches||12 Bars- Each 7’6″|
|8′||10′||1′ 4 5/16″ x 18″||3 Inches||8 Bars 7’6″ + 6 Bars 9’6″|
|10′||10′||1′ 4 5/16″ x 1′ 4 5/16″||3 Inches||16 Bars 9’6″|
|10′||12′||1′ 4 5/16″ x 1′ 5 1/4″||3 Inches||8 Bars 11’6″ + 9 Bars 9’6″|
|12′||12′||1′ 5 1/4″ x 1′ 5 1/4″||3 Inches||18 Bars 11’6″|
|20′||20′||18″ x 18″||3 Inches||28 Bars 19’6″|
What Size Rebar Is Needed For Pool Deck
The rebar you will likely need for a pool deck is typically the same as you would need for a concrete patio. Since these tend to be similar in dimensions and function, it’s a good jumping-off point for calculations.
According to Gra-Rock, “There are three different sizes of rebar which are needed for home projects are usually #3, #4, and #5.
The rebar size #3 is used for driveways and patios.”
What Can Happen If I Don’t Use Rebar In Pool Deck
If your pool deck is less than four inches deep, then you don’t need rebar. Nothing untoward is likely to happen beyond normal weathering and aging for these thinner slabs.
However, if you have a thicker slab of concrete that bears more weight and choose not to reinforce the tensile strength appropriately, it will probably break.
Keep in mind that this isn’t some rapid or explosive event. You will likely start to see small cracks within a few months to a year, and they will get larger over time.
You can fill these with more cement, but ultimately that is only a temporary fix, and it will not stop the cracks from widening as the slab breaks up ponderously slowly.
Eventually, you will need to replace a poorly constructed slab. Regrettably, this is a waste of time, and broken chunks of cement tend to be jagged, which poses a trip and fall hazard and other potential for injuries.
Rebar vs Wire Mesh For Concrete Deck
Many concrete decks don’t require rebar. In fact, wire mesh can be the better option. Since these outdoor spaces don’t necessarily have the same tensile strength requirements, a mesh can add stability at a lower cost.
If your concrete deck is only four inches thick, consider using the easy, durable method below.
- First, use a vibrating plate to compact the soil below, so it doesn’t move easily. You want around 95% proctor density.
- Next, place control joints perpendicular to your pool. You want these to be about ten feet apart, though they can be up to fifteen.
- Finally, add a fiber or steel mesh to the center of the slab.
Is Rebar Needed For Stamped Concrete Deck
The pattern or stamping on top of a concrete deck is not what determines the need for rebar. If your space is small or the thickness of the cement is thinner, reinforcing it isn’t a big deal.
However, you need the soil compacted whether you use rebar or not.
For large concrete decks, you always need reinforcement. Cracking can happen over time regardless of how careful and thorough you are.
Using rebar to reinforce the tensile strength will help minimize cracks and hold the structure of the slab together.
Helpful Tips To Know If A Pool Deck Needs Rebar
As a general rule, assume that your pool deck needs rebar. You can opt for wire mesh in smaller spaces or with thinner concrete slabs, but nothing beats rebar for added tensile strength.
Here are more helpful tips to know if a pool deck needs rebar.
- Although five inches depth is the general minimum, it’s not a hard rule. A pool deck less than five inches deep may need extra support if the area is prone to earthquakes. However, pool decks shouldn’t be less than about four inches deep, so it’s a minimal difference in size.
- Make sure the rebar is in the right place if you use it. The inexperienced may lay rebar in contact with the ground and pour over it, but this leaves the rebar exposed and will eventually cause it to rust out of the cement, leaving it worse than if it had none at all. Rebar goes in the middle of the pour, like the icing between two cake layers.
- You can reinforce smaller slabs of concrete even when it’s not necessary. Doing this will extend their working life.
Your pool deck probably needs rebar. Adding strength to something you intend to have in place for years or decades is always a wise plan.
Even when a slab is only four inches thick, consider adding a wire mesh at least. It is worth the extra effort and expense to have a high-quality deck.
Make sure you space the bars correctly and don’t let them touch the ground or ‘stick out’ anywhere because this will lead to rust issues.