What is the maximum spacing between control joints?

What is the maximum spacing between control joints?

Rule #5: For better crack control keep the maximum distance between joints in feet at 2 to 2.5 times the slab thickness in inches. For a 6 in. thick slab, the maximum joint spacing should be limited to 12 to 15 ft. Exceeding a joint spacing of 15 ft.

How often do you need control joints 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).

What distance should an expansion joint be?

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.

How deep do control joints need to be?

Depth of control joint is important A basic rule to follow when judging how deep a control joint should be is that it should be roughly 1/4 the depth of the concrete. If a concrete slab is 4 inches thick, the depth of the control joint should be 1 inch.

How far apart should construction joints be in concrete?

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 ¼ thickness of the slab. Saw-cut joints should be done within 4 to 12 hours after the concrete has been finished.

How deep do you cut control joints in concrete?

A good rule of thumb is to cut the joints one-quarter to one-third the slab thickness. 2 For a 6-inch-thick slab, that means cutting 1.5 to 2 inches deep.

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.

What is the interval of expansion joint for lengthy slab?

In brick or stone masonry expansion joints normally need not be necessary, except in the case of long walls exceeding 30 m in length; in such long walls the expansion joints shall be not less than 15 mm wide and shall be spaced not more than 30 m apart.

How far apart should expansion joints be in concrete sidewalk?

Maximum Joint Spacing should be 24 to 36 times the thickness of the slab. 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 ¼ thickness of the slab.

How big can a concrete slab be without control joints?

Concrete control joints should be no less than ¼ of the total thickness of the slab (1” deep for a 4” thick pour) and placed no less than 2-3 times (in feet) the thickness (in inches) of the slab (8-12 feet apart for a 4” thick pour).

What happens if you dont trowel concrete?

If you haven’t done this before or only done it, a few times you are likely to make two mistakes; troweling too soon and troweling too much. Both of these have the effect of pulling fines and water to the surface. This can lead to a weakened surface, tiny cracks, and a white dusty surface.

How soon after pouring concrete should you wet it?

To put it simply, the goal is to keep the concrete saturated during the first 28 days. The first 7 days after installation you should spray the slab with water 5-10 times per day, or as often as possible. Once the concrete is poured the curing process begins immediately.

What should the spacing be for concrete control joints?

Plan out your control joint spacing 24-36 times the depth of your concrete slab. Always cut off of your corners as soon as possible because this is usually the first place cracking starts. The depth of your concrete joints should be 25% of the depth of your slab.

How big should the spacing of joints be?

Contraction/Control 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).

How often should joints be placed on a 5 inch slab?

If you have a 5 inch slab and multiply it by 24 to 32 you will find that your joints should be placed every 120 to 180 inches or 10 to 15 feet Or another way to figure this out is to times it by 2 or 3 in feet. So for example if you take a 6 inch slab times 2 is twelve feet or times 3 is 18.

Where to place control joints in a wall?

When you get to an offset in the wall, place a control joint either at an interior corner or two control joints 20 to 25 ft. (6 – 8m) apart.