What is a concrete waffle slab?
A waffle slab or two-way joist slab is a concrete slab made of reinforced concrete with concrete ribs running in two directions on its underside. The name waffle comes from the grid pattern created by the reinforcing ribs.
How does a waffle slab work?
Waffle slabs are a reinforced concrete footing and slab system constructed on the ground. Waffle slabs achieve their strength by varying the height of the slab above ground. The higher the slab above ground – the deeper the beams. The deeper the beams – the more stiffness the system has.
Why are waffle slabs used?
Waffle slabs are used for larger span slabs or floors and used when there is limited requirement for number of columns. The load carrying capacity of waffle slab is greater than the other types of slabs. They provide good structural stability along with aesthetic appearance.
How do you calculate concrete for a waffle slab?
Concrete Calculations
- Multiply the total lineal meter of the edge beam by 150×150.
- Multiply total lineal meter of edge beam by the total height of slab by 50mm. Divide total m^2 of slab by 8.35 on 260 mm high slab.
- Add totals of the earlier steps together and then add a further 3% to allow for wastage.
How much does it cost for 1 cubic Metre of concrete?
The average cost of concrete is anywhere from $200 – $300 per m3 (cubic metre), though you could pay as much as $350 for 40 MPa strength. Variations in cost are due to local prices differing slightly, the type of concrete you order, and any additives or admixtures required.
How many bags of concrete do I need for a 10×20 slab?
A 60-pound bag yields . 017 cubic yards, and an 80-pound bag yields . 022 cubic yards. For a 10 x 10 slab, you would need 77 60-pound bags or 60 80-pound bags.
What is the formula for mixing concrete?
The safest bet for any concrete mix is four-two-one: four parts crushed rock; two parts sand; and one part cement. The four-two-one mix, obviously, has seven parts. Conveniently, when mixing concrete, the ratio can be mixed on any range of scales.
How much does 2 yards of concrete cost?
According to the NRMCA – Ready Mixed Concrete Industry Data Survey, the average cost of concrete in 2018 was $120 per cubic yard, or $240 for the 2 cubic yards needed for a typical 10-by-10-foot patio….Bulk Concrete Prices.
| Cubic Yards | Price Range |
|---|---|
| 1* | $140-$200 |
| 2* | $280-$400 |
| 3* | $420-$600 |
| 4* | $560-$800 |
Can I pour a 2 inch concrete slab?
If done properly, new concrete can often be poured right over an existing slab. For this to be feasible, the contractor needs to pour at least 2 inches thick, use smaller aggregate, and incorporate reinforcement such as welded wire mesh or fiber mixed into the concrete.
Is it cheaper to mix your own concrete?
One of the least expensive ways to get concrete is to mix your own. You can buy bags of the mix from a home improvement store. Typically, you only have to add water for it to be ready to pour. Otherwise, you risk getting a weaker concrete once it cures, which could lead to cracks or crumbles within a couple of years.
How much does a 30×30 concrete slab cost?
How much is the cost of a 30×30 concrete slab? A 30×30 foot concrete slab costs about $5,400 including installation. This is for 6-inch thickness, but can go up or down depending on what your concrete pro recommends.
How much does a 30×30 shop cost?
30×30 Garage Prices
| Style | Price |
|---|---|
| Regular Roof | $8,585 |
| Boxed-Eave | $9,285 |
| Vertical Roof | $9,735 |
What is the difference between a concrete slab and a cement slab?
What is the difference between cement and concrete? Although the terms cement and concrete often are used interchangeably, cement is actually an ingredient of concrete. Concrete is a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and portland cement.
How much is a 24×24 concrete slab?
A typical 24×24 garage slab costs between $3,057 and $5,944 with prices ranging from $5.31 to $8.31 per square foot for a 4” reinforced slab of concrete, and $6.83 to $10.32 per square foot for a 6” slab of reinforced concrete.
How much does a 20×20 concrete patio cost?
Cost to Install Concrete Patio by Size
| Size in Feet | Square Footage | Price Range |
|---|---|---|
| 12×14 | 168 | $1,400 – $4,000 |
| 15×15 | 225 | $1,800 – $5,500 |
| 16×18 | 288 | $2,300 – $7,200 |
| 20×20 | 400 | $3,000 – $10,000 |
How thick does a concrete slab need to be for a garage?
four-inches
Can you pour concrete over grass?
Cheap and versatile and easy to pour, concrete will last you years down the road. You can pour it just about everywhere—including on the grass. Although it takes a little work, pour concrete over grass to create that walkway you always wanted or that mowing preventative you could previously only dream about.
Is gravel necessary under concrete?
Whether you pour concrete for a walkway or patio, a strong gravel base is required to prevent the concrete from cracking and shifting. Gravel is especially important in clay soil because it doesn’t drain well, which results in water pooling under the concrete slab and slowly eroding the soil as it finally drains.
Do you need plastic under concrete driveway?
If the weather is excessively hot, windy, or dry, the concrete should be protected by covers. This prevents rapid evaporation before finishing begins and avoids plastic shrinkage cracks.
How thick should a cement patio be?
4 inches
How much would a 40×60 concrete slab cost?
How much does a 40×60 concrete slab cost? It would be about $8,500 to $12,000 for a 40×60 foot concrete slab, 6 inches thick. That’s based on national averages of around $5 per square foot for a fully engineered, finished concrete slab, including labor and materials.
Is it OK if it rains after pouring concrete?
If the concrete is still fresh (around 2-4 hours after pouring), it’s important to cover the surface to protect it. However, once the concrete has been finished (between 4-8 hours after pouring), and has set hard enough for walking on, the effects of rain should be minimal.
How long does it take for 4 inches of concrete to cure?
When waiting for concrete to dry, keep these timeframes in mind: 24 to 48 hours – after inital set, forms can be removed and people can walk on the surface. 7 days – after partial curing, traffic from vehicles and equipment is okay. 28 days – at this point, the concrete should be fully cured.
Is Hoover Dam concrete still curing?
Concrete in the core portion of the gigantic Hoover dam in Nevada, USA is still continuing to cure according to engineers. That is in spite of the fact that the dam was built way back in 1935 and a huge network of 1 inch dia.
Should you wet concrete while curing?
ANSWER: Keeping concrete moist helps the curing process. If too much water is lost from the concrete through evaporation, the hardening process slows down or ceases. Concrete continues to gain strength after pouring for as long as it retains moisture, but the longer it moist-cures, the slower the rate of strength gain.
When can I remove concrete formwork?
Walls and columns can be removed after about 24-48 hours. Slabs, with their props left under them, can typically be removed after 3-4 days.