Guides

Does a garage slab need a vapor barrier? The 2021 IRC requires a 10-mil retarder under floors but exempts garages. See what it says and what to check.

Concrete block sizes and types explained: nominal vs specified dimensions, standard widths, unit shapes, density classes, and C90 strength and tolerance.

How wide should a sidewalk be? See the ADA 36 in minimum, PROWAG’s 48 in, FHWA’s 4 to 8 ft range, two city examples and what the sources do not state.

How tall can a retaining wall be without an engineer? See what the 2021 IRC and IBC say, where height is measured, and why 4 ft is a permit line only.

Rebar size chart with diameter, area and weight per foot for #3 to #18, plus why #5 means 5/8 in, why #9 breaks the rule, and how to read the marks on a bar.

When to seal new concrete: compare QUIKRETE and NRMCA timing windows in hours, the weather limits, and what the sources leave out about already-cured slabs.

How to make a concrete countertop with QUIKRETE Countertop Mix: forms, water, mixing, slump, curing and demold times from its 2007 and 2018 data sheets.

How deep should footings be? See the 12 inch model-code floor, how the local frost line is set, soil and size rules, and when the inspector checks the trench.

Should you water new concrete? See when to start wet curing, how long sources say to keep it moist, and when to hold off, such as freezing weather.

How to pour self-leveling concrete in the right order: clean, seal gaps, prime, mix, pour and protect, with what ARDEX, CBP, LATICRETE and MAPEI sheets say.