Concrete guides
Concrete Guides & How-Tos
Plain-English answers to the questions that come up before every pour: curing time, slab thickness, rebar, PSI, and more. Each links to the calculator that does the math.
Concrete Glossary
Plain-English definitions of every concrete and cement term, each linked to a guide.
Open glossary →How Long Does Concrete Take to Cure?
How long does concrete take to cure? Walkable in 24–48 hours, 70% strong at 7 days, fully cured at 28 days.
Read guide →How Thick Should a Concrete Slab Be?
How thick should a concrete slab be? 4 inches for patios and floors, 5–6 inches for driveways and vehicle loads.
Read guide →Does Concrete Need Rebar?
Does concrete need rebar? Structural slabs, driveways, and footings do; thin walkways often don't.
Read guide →How Long Before You Can Drive on New Concrete?
How long before you can drive on new concrete? Cars after 7 days, heavy vehicles after 28 days.
Read guide →How Much Water Per Bag of Concrete?
How much water per bag of concrete? About 6 pints for an 80 lb bag, 4.
Read guide →What PSI Concrete Do I Need?
What PSI concrete do you need? 3,000–3,500 for patios and slabs, 4,000 for driveways and footings, 4,500+ for heavy duty.
Read guide →How Deep Should Footings Be?
How deep should footings be? Below the frost line, 12 inches in the south to 48+ in the north, and into undisturbed soil.
Read guide →How to Pour a Concrete Slab
How to pour a concrete slab, step by step: plan, excavate, form, base, reinforce, pour, finish, and cure.
Read guide →Concrete vs Cement: What's the Difference?
Concrete vs cement: what's the difference? Cement is an ingredient; concrete is the finished material made from cement, sand, gravel, and water.
Read guide →What Temperature Can You Pour Concrete?
What temperature can you pour concrete? Aim for 50–90°F: about 50°F is the practical minimum and 95°F the max at placement.
Read guide →Dry Pour Concrete: Does It Actually Work?
Does dry pour concrete work? Yes for non-structural pads, but it cures weaker than mixed concrete and isn't for driveways, footings, or load-bearing work.
Read guide →Concrete Mix Ratio: The 1:2:3 Mix
What is the ratio for concrete? The classic mix is 1:2:3: 1 part cement, 2 parts sand, 3 parts gravel, plus half a part water.
Read guide →How to Mix Concrete
How do you mix concrete? Combine the dry materials first, then add water slowly to a plastic, workable consistency.
Read guide →Why Does Concrete Crack?
Why does concrete crack? Mostly from shrinkage as it dries, plus settlement, temperature, and overload.
Read guide →Concrete Control Joints
How far apart should control joints be? About 2 to 3 times the slab thickness in feet, cut at least a quarter of the depth.
Read guide →How to Finish Concrete
How do you finish concrete? Screed it level, float it, edge and joint it, then trowel smooth or broom for grip.
Read guide →Gravel Base for Concrete
How much gravel under a concrete slab? About 4 inches of compacted crushed stone is standard.
Read guide →How to Seal Concrete
Should you seal concrete? Yes.
Read guide →Concrete vs Asphalt Driveway
Concrete or asphalt driveway? Asphalt is cheaper upfront and better in cold; concrete lasts longer with less upkeep.
Read guide →Rebar Size and Spacing
What size rebar for a slab? Usually #3 or #4 bar in a 12 to 18 inch grid.
Read guide →What Is Concrete Made Of?
What is concrete made of? Cement, water, sand, and gravel.
Read guide →How to Cure Concrete
How do you cure concrete? Keep it moist for at least 3 to 7 days by wet-covering, sheeting, or a curing compound.
Read guide →Concrete Efflorescence
What is the white residue on concrete? Efflorescence: salt left behind as moisture moves through and evaporates.
Read guide →Concrete Spalling
Why is concrete flaking on the surface? Spalling, usually from freeze-thaw, de-icing salt, or finishing mistakes.
Read guide →Concrete vs Pavers
Concrete or pavers for a patio or driveway? Poured concrete is cheaper and faster; pavers cost more but look premium.
Read guide →Fast-Setting Concrete
What is fast-setting concrete? A rapid-set mix that hardens in 20 to 40 minutes, ideal for setting posts without mixing.
Read guide →Concrete Slump
What is concrete slump? A measure of how wet and workable fresh concrete is, typically 3 to 5 inches for slabs.
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