How far apart do you put expansion 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). So for a 4 inch thick concrete slab, expansion joints should be no more than 8 to 12 feet apart.
What is the maximum distance between expansion joints?
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 big can a concrete slab be without expansion 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).
Where should concrete expansion joints be placed?
Expansion joints are put in place before the concrete is poured. Expansion joints are used to allow the slab to move and not put stress on whatever it abuts. These joint are placed where a slab meets a building, where a slab meets another slab, and where a pool deck meets the coping.
How wide should an expansion joint be?
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.
How do you cut expansion joints in concrete slab?
MORE JOINTING TIPS Cut joints 25% of the depth of the slab. A 4″ thick slab should have joints 1″ deep. Groover tools cut joints in fresh concrete. Saw cutting cuts joints as soon as the concrete is hard enough that the edges abutting the cut don’t chip from the saw blade.
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.
How far apart should control joints be?
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 happens if you don’t put expansion joints in concrete?
If you have a concrete floor in your commercial building, you know expansion joints are necessary to allow for the natural expansion and contraction that occurs from temperature changes. Without these joints, large cracks can travel across your floor, creating costly damage.
Do I need to cut expansion joints in concrete?
Timing is very important. Joints should be sawed as soon as the concrete will withstand the energy of sawing without raveling or dislodging aggregate particles. For most concrete mixtures, this means sawing should be completed within the first six to 18 hours and never delayed more than 24 hours.
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 wide should a concrete joint be?
The joint depth should be AT LEAST ¼ of the slab thickness. A narrow joint width between 1/10 to 1/8 inches wide is a common way to avoid joint sealing. Concrete naturally wants to generally crack in squares. The jointing pattern should be cut as close to squares as possible.
Why do we need an expansion joint in slab?
– thermal expansion and contraction caused by temperature changes, – sway caused by wind, – seismic event like earthquakes etc.
What is the purpose of expansion joints in concrete?
The Purpose of Joints in Concrete Slabs. As concrete moves,if it is tied to another structure or even to itself,we get what’s called restraint,which causes tensile forces
How to fill space between concrete slabs?
Remove all old caulk from the joint to be filled.
How to caulk a concrete expansion joint?
– Sweep the area of concrete containing the sealer you want to remove. – Apply a chemical stripper over the area by pouring it and spreading the stripper out using a large squeegee or old broom. – Let the chemical stripper set for at least 15 minutes.