Floor slab specific weight: weight of hollow and solid slabs
Reinforced concrete floor slabs do not always occupy the main position in the overall construction estimate, but this structural element cannot be ignored by mass. At the project development stage, it is necessary to calculate what loads the walls and foundation of the building can withstand, and then choose a suitable type of intermediate floor.
Types of Reinforced Concrete Floor Slabs
The variety of modifications of this construction element is relatively small; all of them are standard because they are produced exclusively according to GOST standards. All existing reinforced concrete product varieties meet safety requirements for the construction of high-rise, low-rise or industrial buildings.
- A solid floor slab is a monolithic product without large internal voids. The weight of a 120 mm thick slab is from 4300 to 7100 kg. The higher the concrete grade, the greater the strength and weight of the floor element. The weight of a 160 mm thick floor slab can reach 8700 kg.
A type of solid floor slab is the supplementary element. The length of such products is standard for full-size slabs, 1.8-5 m, but the width is much smaller, as is the weight, up to 1500 kg.
- Hollow-core, or lightweight, floor slabs have less weight because their body is penetrated by technological openings of a certain shape. Mostly these are round chambers with diameters from 140 to 159 mm, PC1 and PC2. There are also hollow-core floor types with elliptical chambers, PG, and differently shaped ones, PB.
The presence of voids in the slab body makes it possible to reduce the mass of standard 6-meter floors to 3 tons. The advantage of hollow-core slabs is good thermal and sound insulation.
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Ribbed reinforced concrete products can be classified as monolithic because they have no internal cavities. These are slabs with increased load-bearing capacity, obtained thanks to side cast-in-place stiffening ribs. Standard 6-meter slabs weigh from 1500 to 3000 kg, while industrial 12-meter giants reach 7000 kg.
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A polystyrene concrete floor slab is a lightweight slab option where thermal insulation material is used as filler. The strength of such slabs is lower than that of classic reinforced concrete products, so allowable loads must be checked according to the manufacturer’s documentation and design calculation. Polystyrene concrete slabs weigh less than classic solid slabs, while their thermal insulation characteristics are higher.
How Much Do Different Floor Slabs Weigh?
Slab weight depends on many factors, in particular the grade of concrete used, the number of reinforcing elements, recesses, voids and other factors.
| Reinforced concrete type | Marking | Size (mm) | Weight (kg) |
| Solid | PRTm-3 | 1600x400x80 | 85 |
| TP-43-8 | 4300x800x220 | 1400 | |
| PTP 24-12 | 2400x1200x120 | 840 | |
| Ribbed | 1P7-2 | 5550x740x400 | 1500 |
| 2PG-5 | 5970x1490x250 | 1230 | |
| 1P3-1 | 5550x1490x400 | 2650 | |
| Hollow-core | PC26.10-8 | 2580x990x220 | 780 |
| PC30.15-8 | 2980x1490x220 | 790 | |
| PC50.12-8 | 4980x1190x220 | 1320 | |
| Polystyrene concrete | 36.10.3 | 3600x1000x300 | 1150 |
| 42.12.3 | 4200x1200x300 | 1610 | |
| 51.15.3 | 5100x1500x300 | 2450 |
Frequently Asked Questions
Can the density of floor slab be used for precise calculations?
The density and weight values for floor slab in this article are reference values. They are suitable for preliminary estimates, but design, construction, production and other critical calculations should be checked against standards, material datasheets or measurement results.
Why can the actual weight of floor slab differ from the table?
The actual weight of floor slab depends on composition, moisture, temperature, porosity, fraction size, material grade and measurement conditions. Because of this, real values may differ from the average table data.
How do you calculate the mass of floor slab from density?
For an approximate calculation, use the formula: mass = density × volume. If the density of floor slab is given in kg/m³ and the volume is in m³, the result will be in kilograms.