How far apart should concrete joints be?

Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. Joint spacing that is greater than 15 feet require the use of load transfer devices (dowels or diamond plates).

How far apart should expansion joints be in concrete?

Usually, expansion joints should be no farther apart than 2 to 3 times (in feet) the total width of the concrete (in inches). So for a 4 inch thick concrete slab, expansion joints should be no more than 8 to 12 feet apart.

How big can a concrete slab be without control joints?

Rule #1 – Keep joints as square as possible. Rule #2 – In order to prevent intermediate cracking, space joints (in feet) no more than 2 – 3 times the slab thickness (in inches).

What is the maximum spacing for expansion joints in a concrete patio?

Maximum Joint Spacing

Historically, the maximum recommended distance or spacing in feet between joints has been two to three times the slab thickness in inches.

What is the maximum distance between expansion joints?

A practical limit between expansion joints for TFR is in the range of 100' to 200', when these roofs are attached to light gage cold- formed purlins. Standing seam roofs are limited by the range of the sliding clips. Depending on the manufacturer, it is in the range of 150' to 200'.

Concrete Joints

At what length do you need expansion joint?

As per IS- 456:2000, structures exceeding 45m in length are designed with one or more expansion joint. As per IS 3414 which is a specific code for joints, it is mentioned as 30m. Expansion joint shall be so provided that the necessary movement occurs with a minimum resistant at joint.

Where do you put expansion joints in concrete?

Placing Tips

Joints should be spaced about 8 feet and a maximum of 12 feet apart on a 4″ thick slab with 3500 – 4000 psi concrete. Saw-cut joints should be done within 4 to 12 hours after the concrete has been finished. Pre-molded joint filler should be used to separate slabs from building walls and footings.

Do I need concrete expansion joints?

Expansion joints are virtually never needed with interior slabs, because the concrete doesn't expand that much—it never gets that hot. Expansion joints in concrete pavement are also seldom needed, since the contraction joints open enough (from drying shrinkage) to account for temperature expansion.

What is the standard guideline for spacing contraction joints to space them in feet?

Joints should be spaced about 10 feet and a maximum of 15 feet. When using joint groove for contraction joints, the joint should be a minimum depth of 1/4 thickness of the slab. Saw-cut joints should be done within four to 12 hours after the concrete has been finished.

How far apart are sidewalk joints?

Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. Joint spacing that is greater than 15 feet require the use of load transfer devices (dowels or diamond plates). Contraction joints may be tooled into the concrete surface at the time of placement.

How many times do you float concrete?

Push the bull float in one direction only across the concrete, keeping its front edge slightly above the surface by raising or lowering the handle. Two or three times is enough. Don't overwork the concrete or you'll weaken it by drawing too much sand and cement to the surface.

Does a garage slab need expansion joints?

Many people understand that wood shrinks and expands as temperature and humidity ebb and flow through the year. But the same thing happens with concrete. That's why it is necessary to include expansion joints along the edges of the concrete garage floor as well as around posts or other protrusions in the slab.

How wide are expansion joints?

Joints should be at least 1/2-inch to 3/4-inch wide. Expansion joints should extend beyond the full depth of the concrete slab. Use a screwdriver to confirm that each joint at least 4-inches deep. Four inches is the minimum depth required for concrete driveways.

How long after pouring concrete should you cut it?

For most concrete work, cutting should take place within the first 6 to 18 hours and never beyond 24 hours. Smaller early-entry saws are available, which may allow cutting to begin within a few hours after placement.

How far apart should dowels be in concrete?

Dowels are typically spaced 12 inches apart either over the entire length of the joint or may be placed in clusters of 3, 4 or 5 that are centered over the wheel paths (as illustrated previously in figure 15).

How many control joints are there in concrete?

CONTROL JOINT SPACING

Space joints (in feet) no more than 2-3 times the slab thickness (in inches). A 4" slab should have joints 8-12 feet apart. When arranging joints, skilled contractors will often use them to create an attractive diamond pattern.

What can you put between concrete joints?

Expansion joints must be sealed with a flexible sealant, like QUIKRETE® Self-Leveling Polyurethane Sealant or QUIKRETE® Non-Sag Polyurethane Sealant…or an expansion joint strip, to prevent water from penetrating the joint and deteriorating the sub-base.

What is the difference between control joint and expansion joint?

Control joints can be isolated within the plane being treated (brick facades, concrete sidewalks) while expansion joints must bisect the entire structure thereby creating a gap throughout all of the building elements—foundation, walls, curtainwalls, plaza decks, parking decks, floors, and roof.

What is the minimum overlap of the expansion joint?

The metal sides of the T-Pren should overlap the metal sheets by a minimum of 25mm and the joint should be made at least 75mm from the neoprene, or 100mm for aluminium and copper due to their better conductivity.

What is the minimum and maximum expansion joint distance in building?

Expansion joint spacing is dictated by the amount of movement that can be tolerated, plus the allowable stresses and/or capacity of the members. As with contraction joints, rules of thumb have been developed (Table 3). These range from 30 to 400 ft (9 to 122 m) depending on the type of structure.

Should I caulk my concrete expansion joints?

Even expansion joints in your concrete driveway should be caulked. They can be the biggest culprit of water under your slabs. Notice how the caulking is slightly lower than the concrete slab around it. This protects the caulk from wear and tear of people walking and driving over it.

How thick does a concrete slab need to be for a garage?

Thickness of Garage Floor Slab

Light Loads – For one to two light cars or trucks, the concrete should be at least four inches thick. Medium Loads – If the garage is used for average-sized vehicles and/or medium to heavy trucks, the concrete needs to be six inches thick.

Can you leave concrete forms on too long?

In short, there is no such thing as leaving concrete forms on for too long, as they will simply continue the curing process as the forms remain in place. However, there is no real need to leave forms on for longer than necessary.

Why do brooms finish concrete?

Sometimes called brushed concrete, a broom is used to create a slip-resistant texture on the surface of the concrete. Concrete finishers have been broom finishing for about as long as there has been concrete. Broom finished thin overlays add skid resistance and upgrade a deteriorating concrete surface.

Can I pour concrete over 2 days?

Although concrete will harden soon after pouring, it's still susceptible to damage from weight during the first four weeks. Wait at least 24 hours before allowing foot traffic, including pets, on a newly poured sidewalk or slab, and don't drive a vehicle on a new driveway for at least 10 days.