What methods can be used to reduce the impact of thinning floor slabs?

Nowadays, many developers make building floor slabs very thin in order to save costs. The thinner the floor slab, the worse the sound insulation. What are some ways to reduce the impact of thinner floor slabs? Today, we'll explain the effects of thinner floor slabs and some solutions, hoping to be helpful to everyone.

I. Acoustic treatment

1. Add sound insulation materials

Sound-absorbing cotton: Sound-absorbing cotton is added to the upper and lower surfaces or the middle layer of the floor slab. Sound-absorbing cotton is a porous material; when sound enters, sound waves reflect back and forth within the pores of the cotton, converting sound energy into heat energy through friction, thus achieving a sound-absorbing effect. For example, fiberglass sound-absorbing cotton has excellent absorption properties for mid-to-high frequency sounds. It can be installed during renovation in the space between the ceiling and the floor slab, or between the floor covering layer and the floor slab, with a thickness generally around 3-10 cm.

Sound insulation felt: This is a high-density material with excellent sound insulation properties. It primarily works by blocking the transmission of sound. It is typically installed on the surface of floors, such as before laying wooden floors, with a layer of sound insulation felt generally 2-5 mm thick. Sound insulation felt can effectively reduce the transmission of impact noise and some airborne noise, especially effective at blocking low-frequency sounds.

Sound insulation panels: These come in various types, including wood and gypsum board. Wood sound insulation panels have a special internal structure that reflects and absorbs sound, making them suitable for walls and ceilings in interior decoration. When used with floors, they enhance sound insulation. Gypsum board, on the other hand, possesses a certain level of quality and sound insulation performance. Multiple layers can be installed to create a good soundproofing structure. For example, installing two 12mm thick layers of gypsum board under a floor slab, with an air gap in between, can effectively block sound transmission.

2. Constructing a floating floor system

Floating floors are an effective sound insulation structure. They primarily involve laying a resilient underlayment on top of the existing floor slab before pouring concrete or laying other flooring materials. The resilient underlayment can be made of materials such as rubber or cork. For example, a 3-5 mm thick rubber resilient underlayment can effectively isolate impact noise. When an impact occurs on the floor slab, the resilient underlayment absorbs the vibration energy, preventing sound from propagating through the structure. Furthermore, floating floor systems can be used in conjunction with materials such as sound-absorbing felt to further enhance sound insulation.

3. Sealing treatment

Sealing gaps and holes in floor slabs is crucial. During construction, floor slabs may develop gaps due to pipes (such as water pipes, electrical conduits, etc.). These gaps can become channels for sound transmission, especially high-frequency sounds. Sealant, fire-retardant putty, and other materials can be used to fill and seal these gaps. For example, where water pipes penetrate the floor slab, a ring seal can be applied with sealant to prevent sound from propagating through these weak points.

II. Structural Strengthening

1. Add local reinforcement measures

Installing beam structures: Adding beams appropriately beneath floor slabs with large spans. Beams can distribute the load on the floor slab, reducing its burden. For example, in large open-plan conference rooms or commercial spaces, adding beams ensures that the floor slab, even with a thinner span, can still safely support the loads of people and equipment. The size and spacing of the beams need to be determined based on specific building structure calculations. Generally, the beam height can be between 30 and 80 centimeters, depending on the span and load-bearing requirements.

Localized thickening measures are adopted: Thickening is performed on key load-bearing areas of the floor slab, such as around columns and corners. This is similar to reinforcing weak points; thickening these areas enhances the overall load-bearing capacity of the floor slab. The extent of the thickening can be determined based on specific structural analysis; generally, a ring-shaped area of ​​about 10-20 centimeters can be thickened around columns.

2. Use high-performance building materials

High-performance concrete: This type of concrete uses higher strength grades, such as C60-C80. These concretes have higher compressive strength and modulus of elasticity, providing sufficient load-bearing capacity even with thinner slabs. Compared to ordinary C30 concrete, C60 concrete can have approximately double the compressive strength, allowing it to adapt to thinner floor slabs while ensuring safety.

High-strength steel bars: Using high-strength steel bars can improve the reinforcement efficiency of floor slabs. For example, the yield strength of HRB500 grade steel bars is much higher than that of HRB335 grade steel bars. Under the same stress conditions, using HRB500 grade steel bars can reduce the amount of steel bars used, while enhancing the load-bearing capacity of the floor slab to compensate for the impact of reduced floor slab thickness.