https://concreteinfo.shop/ Independent, sourced answers about concrete and cement for US homeowners, contractors and specifiers. Bilingual, ad-supported, never a lead-gen site. en-us https://concreteinfo.shop/questions/safety-and-silica/can-concrete-burn/ https://concreteinfo.shop/questions/safety-and-silica/can-concrete-burn/ Concrete does not burn, but trapped water flashing to steam can blow chunks off it in a fire. Wet cement also burns skin chemically, and that is more common. https://concreteinfo.shop/questions/weather-hot-and-cold/can-i-lay-concrete-in-cold-weather/ https://concreteinfo.shop/questions/weather-hot-and-cold/can-i-lay-concrete-in-cold-weather/ Yes, with heated mix water, unfrozen ground, blankets staged before delivery and a longer protection period. What suppliers do, and when to wait for spring. https://concreteinfo.shop/questions/weather-hot-and-cold/can-you-lay-concrete-in-the-rain/ https://concreteinfo.shop/questions/weather-hot-and-cold/can-you-lay-concrete-in-the-rain/ You can, but the surface has to stay protected. Rainwater worked into fresh concrete raises the water-cement ratio and leaves a weak, dusting top layer. https://concreteinfo.shop/questions/pouring-and-placement/can-you-pour-concrete-over-concrete/ https://concreteinfo.shop/questions/pouring-and-placement/can-you-pour-concrete-over-concrete/ Yes, if the old slab is sound. You either bond a new layer to a prepared surface or float an unbonded overlay on a bond breaker. A moving slab has to come out. https://concreteinfo.shop/questions/contractors-and-hiring/do-it-yourself-concrete-lifting-foam/ https://concreteinfo.shop/questions/contractors-and-hiring/do-it-yourself-concrete-lifting-foam/ DIY polyurethane kits can raise one small sunken slab, but they cannot fix the void's cause. How the foam works, what it costs, and how it fails. https://concreteinfo.shop/questions/contractors-and-hiring/do-it-yourself-concrete-lifting/ https://concreteinfo.shop/questions/contractors-and-hiring/do-it-yourself-concrete-lifting/ DIY concrete lifting means raising a settled slab with a consumer foam kit. It works on small isolated slabs and fails on driveways, garages, and foundations. https://concreteinfo.shop/questions/codes-permits-and-inspection/do-you-need-a-permit-to-lay-concrete/ https://concreteinfo.shop/questions/codes-permits-and-inspection/do-you-need-a-permit-to-lay-concrete/ Sometimes. Replacing flatwork in kind is often exempt; new structural work, right-of-way aprons and drainage changes usually are not. Only your city can say. https://concreteinfo.shop/questions/rebar-and-reinforcement/does-pouring-concrete-over-rusted-rebar-stop-rust/ https://concreteinfo.shop/questions/rebar-and-reinforcement/does-pouring-concrete-over-rusted-rebar-stop-rust/ Yes — sound concrete is alkaline enough to passivate steel and halt corrosion. Light surface rust is fine and helps bond. Loose scale and section loss are not. https://concreteinfo.shop/questions/weather-hot-and-cold/how-cold-can-you-pour-concrete/ https://concreteinfo.shop/questions/weather-hot-and-cold/how-cold-can-you-pour-concrete/ Below 40 °F for three straight days, ACI 306 cold-weather protection applies. Fresh concrete freezes near 25 °F, and freezing before 500 psi is permanent. https://concreteinfo.shop/questions/estimating-and-quantities/how-do-you-figure-concrete-in-yards/ https://concreteinfo.shop/questions/estimating-and-quantities/how-do-you-figure-concrete-in-yards/ Multiply length by width by thickness in feet, then divide by 27. Worked examples, a coverage table, round and irregular shapes, and how much waste to add. https://concreteinfo.shop/questions/driveways/how-long-does-concrete-driveway-last/ https://concreteinfo.shop/questions/driveways/how-long-does-concrete-driveway-last/ A concrete driveway placed and cured properly lasts decades — commonly 30 years or more, and far longer where it is not exposed to deicing salt. What https://concreteinfo.shop/questions/curing-and-drying-time/how-long-does-concrete-take-to-dry/ https://concreteinfo.shop/questions/curing-and-drying-time/how-long-does-concrete-take-to-dry/ Concrete is walkable in 24–48 hours and takes vehicles at 7 days, but it keeps gaining strength for 28 days. Drying and curing are not the same thing. https://concreteinfo.shop/questions/curing-and-drying-time/how-long-does-it-take-for-concrete-to-settle/ https://concreteinfo.shop/questions/curing-and-drying-time/how-long-does-it-take-for-concrete-to-settle/ Placing a concrete slab is usually a one-day operation; the schedule around it is what takes time. Excavation and base preparation come first, forming and https://concreteinfo.shop/questions/curing-and-drying-time/how-long-does-it-take-for-driveway-concrete-to-dry/ https://concreteinfo.shop/questions/curing-and-drying-time/how-long-does-it-take-for-driveway-concrete-to-dry/ Keep a concrete driveway continuously moist for three to seven days — the NRMCA minimum. Design strength is measured at 28 days. Foot traffic is usually https://concreteinfo.shop/questions/curing-and-drying-time/how-long-for-concrete-to-cure/ https://concreteinfo.shop/questions/curing-and-drying-time/how-long-for-concrete-to-cure/ Concrete needs at least 3 to 7 days of moist curing, held damp and above 50 °F. Curing is what builds strength — drying is a separate process entirely. https://concreteinfo.shop/questions/fence-posts-and-setting/how-many-50lb-bags-of-concrete-per-fence-post/ https://concreteinfo.shop/questions/fence-posts-and-setting/how-many-50lb-bags-of-concrete-per-fence-post/ An 80 lb bag yields about 0. 60 ft³, so a cubic yard (27 ft³) takes roughly 45 bags. A 60 lb bag is about 0. 45 ft³ or 60 bags per yard; 50 lb is about https://concreteinfo.shop/questions/estimating-and-quantities/how-many-80-lb-bags-of-concrete-in-a-yard/ https://concreteinfo.shop/questions/estimating-and-quantities/how-many-80-lb-bags-of-concrete-in-a-yard/ Bag yields come off the manufacturer data sheet. An 80 lb bag yields about 0.60 ft³, so a cubic yard (27 ft³) takes roughly 45 bags. A 60 lb bag is about https://concreteinfo.shop/questions/estimating-and-quantities/how-many-bags-of-concrete-do-i-need/ https://concreteinfo.shop/questions/estimating-and-quantities/how-many-bags-of-concrete-do-i-need/ One 80 lb bag yields about 0.60 ft3, so a cubic yard takes roughly 45 bags. Get your volume in cubic feet, divide by the yield on the bag, then add waste. https://concreteinfo.shop/questions/estimating-and-quantities/how-many-quarts-for80-lbs-of-concrete-mix/ https://concreteinfo.shop/questions/estimating-and-quantities/how-many-quarts-for80-lbs-of-concrete-mix/ Normal-weight concrete runs about 150 lb per cubic foot, which is 4,050 lb per cubic yard — a little over two tons. For a concrete slab, one cubic yard https://concreteinfo.shop/questions/repair-and-resurfacing/how-many-sq-ft-does-sakrete-flocoat-concrete-resurfacer/ https://concreteinfo.shop/questions/repair-and-resurfacing/how-many-sq-ft-does-sakrete-flocoat-concrete-resurfacer/ Multiply length × width × thickness in feet and divide by 27 for cubic yards. Convert inches first — 4 inches is 0.333 ft. For a concrete overlay, https://concreteinfo.shop/questions/estimating-and-quantities/how-many-yards-of-concrete-in-a-truck/ https://concreteinfo.shop/questions/estimating-and-quantities/how-many-yards-of-concrete-in-a-truck/ A ready-mix truck typically carries 8–10 cubic yards, but capacity is supplier-set with no national standard. Short load fees, truck counts, and time limits. https://concreteinfo.shop/questions/estimating-and-quantities/how-much-concrete-do-i-need/ https://concreteinfo.shop/questions/estimating-and-quantities/how-much-concrete-do-i-need/ Multiply length by width by thickness in feet, divide by 27, and add about 10% for waste. One cubic yard covers 81 square feet at 4 inches thick. https://concreteinfo.shop/questions/estimating-and-quantities/how-much-concrete-for-12-sonotube/ https://concreteinfo.shop/questions/estimating-and-quantities/how-much-concrete-for-12-sonotube/ Multiply length × width × thickness in feet and divide by 27 for cubic yards. Convert inches first — 4 inches is 0.333 ft. For a concrete column or pier, https://concreteinfo.shop/questions/fence-posts-and-setting/how-much-concrete-for-fence-post/ https://concreteinfo.shop/questions/fence-posts-and-setting/how-much-concrete-for-fence-post/ A 4x4 post in a 12-inch hole takes about 1.75 cubic feet, roughly three 80-lb bags. Hole sizing rules, a bag table, and totals for a whole fence line. https://concreteinfo.shop/questions/fence-posts-and-setting/how-much-concrete-per-fence-post/ https://concreteinfo.shop/questions/fence-posts-and-setting/how-much-concrete-per-fence-post/ Most fence posts take one to three bags. Size the hole at 3x the post width and one-third the post height, then read the bag count off the table below. https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-a-concrete-footing-cost/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-a-concrete-footing-cost/ A concrete footing runs priced by linear foot rather than square foot. The ready-mix itself is $110 to $205 per cubic yard, with most of the US between https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-a-concrete-pool-cost/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-a-concrete-pool-cost/ A pool deck runs $9 to $25 per square foot installed. The ready-mix itself is $110 to $205 per cubic yard, with most of the US between $130 and $180 — https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-a-concrete-sidewalk-cost-per-foot/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-a-concrete-sidewalk-cost-per-foot/ A concrete sidewalk runs $6 to $12 per square foot installed. The ready-mix itself is $110 to $205 per cubic yard, with most of the US between $130 and https://concreteinfo.shop/questions/estimating-and-quantities/how-much-does-a-yard-of-concrete-weigh/ https://concreteinfo.shop/questions/estimating-and-quantities/how-much-does-a-yard-of-concrete-weigh/ A cubic yard of concrete weighs about 4,000 lb, roughly 2 tons. Here is the density math, what shifts it, and what the weight means for hauling and access. https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-concrete-block-weight/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-does-concrete-block-weight/ A standard 8-inch hollow concrete block weighs about 26 to 38 pounds depending on its density class. Typical weights by size, plus what a full pallet runs. https://concreteinfo.shop/questions/cost-and-pricing/how-much-is-a-concrete-driveway/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-is-a-concrete-driveway/ A concrete driveway runs $5 to $21 per square foot installed. The ready-mix itself is $110 to $205 per cubic yard, with most of the US between $130 and https://concreteinfo.shop/questions/cost-and-pricing/how-much-is-a-yard-of-concrete/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-is-a-yard-of-concrete/ A cubic yard of concrete runs $110 to $205 delivered, and most of the US falls between $130 and $180. Sources disagree sharply — here is our methodology. https://concreteinfo.shop/questions/cost-and-pricing/how-much-to-rent-a-concrete-mixer/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-to-rent-a-concrete-mixer/ The tools for a concrete slab are a screed board, a bull float, an edger, a groover for joints, a magnesium or wood hand float, and a steel trowel only if https://concreteinfo.shop/questions/cost-and-pricing/how-much-will-a-concrete-patio-cost/ https://concreteinfo.shop/questions/cost-and-pricing/how-much-will-a-concrete-patio-cost/ A concrete patio runs $5 to $18 per square foot installed. The ready-mix itself is $110 to $205 per cubic yard, with most of the US between $130 and $180 https://concreteinfo.shop/questions/ready-mix-delivery/how-tall-is-a-concrete-truck/ https://concreteinfo.shop/questions/ready-mix-delivery/how-tall-is-a-concrete-truck/ Most ready-mix trucks stand roughly 11 to 13 feet tall. Federal law sets no height limit, so measure your wires, branches, carport and garage soffit first. https://concreteinfo.shop/questions/slabs-and-foundations/how-thick-basement-concrete-floor/ https://concreteinfo.shop/questions/slabs-and-foundations/how-thick-basement-concrete-floor/ A basement floor is poured 4 inches over a vapor retarder. Typical strength is 3,000 to 3,500 psi (21–24 MPa), no air entrainment needed indoors. https://concreteinfo.shop/questions/garage-floors/how-thick-concrete-garage-floor/ https://concreteinfo.shop/questions/garage-floors/how-thick-concrete-garage-floor/ Four inches suits passenger cars; 5 to 6 inches for heavy vehicles, lifts, or shop equipment. ACI 332 sets 4,000 psi with air entrainment for freezing. https://concreteinfo.shop/questions/footings-and-frost/how-thick-is-a-concrete-slab-foundation/ https://concreteinfo.shop/questions/footings-and-frost/how-thick-is-a-concrete-slab-foundation/ The slab field is typically 4 inches thick, with thickened edges and footings going much deeper. Thickness and footing depth are engineer and code specified. https://concreteinfo.shop/questions/driveways/how-thick-should-a-concrete-driveway-be/ https://concreteinfo.shop/questions/driveways/how-thick-should-a-concrete-driveway-be/ Four inches is standard for cars, 5 to 6 inches for RVs and heavy trucks. Strength, air entrainment, and a compacted subgrade matter as much as thickness. https://concreteinfo.shop/questions/patios-and-walkways/how-thick-should-a-concrete-patio-be/ https://concreteinfo.shop/questions/patios-and-walkways/how-thick-should-a-concrete-patio-be/ Four inches is standard for a residential patio. Go to 5–6 inches under a hot tub, outdoor kitchen or vehicle, and put all of it on a compacted granular base. https://concreteinfo.shop/questions/garage-floors/how-thick-should-concrete-be-for-a-garage/ https://concreteinfo.shop/questions/garage-floors/how-thick-should-concrete-be-for-a-garage/ Four inches suits passenger cars. Go to 5–6 inches for trucks, RVs or a lift, and specify 4,000 psi with air entrainment where road salt or freezing reach it. https://concreteinfo.shop/questions/patios-and-walkways/how-thick-sidewalk-concrete/ https://concreteinfo.shop/questions/patios-and-walkways/how-thick-sidewalk-concrete/ A concrete sidewalk is poured 4 inches. Typical strength is 3,500 to 4,000 psi (24–28 MPa). Underneath it goes 4 inches of compacted base. To size the https://concreteinfo.shop/questions/demolition-and-removal/how-to-break-up-concrete/ https://concreteinfo.shop/questions/demolition-and-removal/how-to-break-up-concrete/ Work from a free edge in small bites, match the tool to the thickness, and control the silica dust. Utility checks, rebar, and what to do with the rubble. https://concreteinfo.shop/questions/commercial-and-structural/how-to-build-a-concrete-block-retaining-wall/ https://concreteinfo.shop/questions/commercial-and-structural/how-to-build-a-concrete-block-retaining-wall/ Compacted base, a dead-level first course, free-draining gravel and a drain outlet. Taller walls and any wall with a load above it need an engineer. https://concreteinfo.shop/questions/cleaning-and-maintenance/how-to-clean-concrete-floors/ https://concreteinfo.shop/questions/cleaning-and-maintenance/how-to-clean-concrete-floors/ Sweep first, then damp mop with a pH-neutral cleaner and rinse. Degrease oil before washing, keep acid as a last resort, and keep rinse water out of drains. https://concreteinfo.shop/questions/staining-and-coloring/how-to-color-concrete/ https://concreteinfo.shop/questions/staining-and-coloring/how-to-color-concrete/ Four ways — integral pigment in the mix, dry-shake hardener, acid stain that reacts with the slab, or water-based stain. Each fades and wears differently. https://concreteinfo.shop/questions/patios-and-walkways/how-to-concrete-patio/ https://concreteinfo.shop/questions/patios-and-walkways/how-to-concrete-patio/ A residential slab is typically 4 inches thick over a compacted granular base, with a 10 mil vapor retarder directly under it where moisture-sensitive https://concreteinfo.shop/questions/tools-and-equipment/how-to-cut-concrete-board/ https://concreteinfo.shop/questions/tools-and-equipment/how-to-cut-concrete-board/ Score and snap cement board for straight cuts, and use a fiber-cement blade with dust control for curves. Dry cutting releases respirable crystalline silica. https://concreteinfo.shop/questions/patios-and-walkways/how-to-cut-concrete-pavers/ https://concreteinfo.shop/questions/patios-and-walkways/how-to-cut-concrete-pavers/ Score with a diamond blade and snap, or cut all the way through with a grinder, saw, or splitter. Tool choice by job size, wet versus dry, and dust control. https://concreteinfo.shop/questions/demolition-and-removal/how-to-dispose-of-concrete/ https://concreteinfo.shop/questions/demolition-and-removal/how-to-dispose-of-concrete/ Take clean broken concrete to a recycler that crushes it into aggregate, or to a C&D landfill. Washout water follows separate state and local stormwater rules.