Are expansion joints necessary?

Expansion joint failure can happen for several reasons, but regardless concrete needs a buffer as it goes through the natural cycles of expansion and contraction. So, this has always been the case, and this is why expansion joints are necessary.

What happens if you don't put expansion joints in concrete?

Concrete expansion joints give the slabs just enough room to move which helps prevent cracks & buckling. Without these joints, even a little movement creates pressure and stress on the concrete. Eventually weak spots can crack or buckle.

Do I need 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.

Do you need to put expansion joints in concrete?

Concrete expansion joints are particularly important where there have been consecutive concrete pours and are also useful when laying concrete within an area bordered by walls or buildings or if objects such as manhole covers need to be incorporated.

What size concrete slab needs an expansion joint?

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 are expansion joints? What they do, why they need to be maintained.

How deep do you cut expansion joints in concrete?

A good rule of thumb is to make your cut ¼ the thickness of your concrete. If ¼ of your slab's thickness, doesn't reach 1” make sure you still cut at least a 1” depth.

Do I need an expansion joint in my wall?

Expansion joints are required in masonry walls. Typically these are at 6 m centres for concrete blockwork and 12 m centres for brickwork. Suitable materials must be used in expansion joints to allow adequate movement of the masonry.

Are expansion joints necessary in sidewalks?

A.: According to several industry sources, expansion joints, even at 50-foot intervals, are not necessary for the sidewalk project. Long stretches of concrete do not require intermediate expansion joints.

Do you need expansion joints in a garage floor?

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.

Do I need an expansion joint between concrete and asphalt?

Generally speaking, you don't need an expansion joint next to asphalt. Asphalt is considered a flexible pavement and expansion joints are needed predominantly for long stretches of concrete that expand.

Do all buildings have expansion joints?

There are many different types of systems for accommodating movement gaps in structures. Expansion joints occur through all parts of a structure to provide complete separation – through floors, walls, ceilings, and roofs (interior & exterior).

Do you have to cut joints in concrete?

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.

What happens if you don't cut concrete?

Late sawing can result in random concrete cracks. Shallow cracks aren't sufficient to prevent uncontrolled cracking while deep cuts are excessively labor intensive and undermine the aggregate interlock in the concrete.

Why do they cut lines in concrete?

WHAT ARE CONTROL JOINTS? Control joints are preplanned cuts in concrete that help control where and how cracks appear in poured concrete. Concrete shrinks as it cures and will change in response to temperature. A large area of poured concrete is likely to crack, especially when up against a foundation or street curb.

How much concrete cracking is acceptable?

Generally, cracks with a width of less than 0.3 mm are acceptable and do not affect the structure. However, they may develop and grow to become structural cracks. Therefore, one should monitor small cracks on houses or structures. Crack width greater than 0.3 mm can create problems for the durability of the structure.

Do I need expansion joints in my driveway?

Concrete expansion joints are important for your sidewalk or driveway. Keeping your joints watertight will prevent moisture from seeping under concrete pads and causing them to heave or sink.

How much do expansion joints cost?

The price to repair expansion joints and control joints greatly depends on how bad the damage is. Preventative joint filling can cost between $1.50 and $3 per lineal foot, but once expansion joint repair or control joint repair is required, the costs can vary from $15 – $100 per lineal foot of joints.

What is the black stuff between concrete slabs?

An expansion joint is a material placed in the cracks (or joints) between concrete slabs to protect the slabs from cracking when they contract and expand as the temperature changes. This material acts as a shock absorber, absorbing the stress from the slab's movement.

How long can you build a wall without an expansion joint?

Movement joints in internal walls are not normally necessary for single dwellings unless the walls are straight and unbroken and over 6m long, in which case the block manufacturer's recommendations should be adopted.

Why do new build houses have expansion joints?

An expansion joint in brickwork and blockwork is a means of solving potential problems caused by movement. This movement could be a result of thermal expansion, moisture movement, creep and structural loading or the effect of chemical changes.

What is the distance between expansion joints?

Joint expansion In jointed reinforced concrete slabs, the maximum expansion joint spacing varies from 25–27 m, and in unreinforced concrete, it ranges from 40 m (for slabs 230 mm thick) to 60 m (for slabs > 230 mm thick).

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 rebar prevent cracking concrete?

Steel reinforcing bars and welded wire reinforcement will not prevent cracking. Reinforcement is basically dormant until the concrete cracks. After cracking, it becomes active and controls crack widths by restricting crack growth.

Do you push or pull a concrete saw?

Always let the saw do the work; simply guide its direction, but don't push it down into the concrete. You only need a quarter-inch cut at this point, but if the saw bites in a bit deeper, that's fine too. This first guided cut will ensure you keep your cuts straight during the rest of the project.