After the installation of the floor stone care wet paste, because the stone and the bonding layer, or the bonding layer and the base layer are not tightly bonded, there is a gap, and a drum-like sound will be heard when it is gently knocked, so it is often called the floor stone hollowing phenomenon. In this article, let’s talk about the problem of stone hollowing.

● Why is the marble empty?
1. Poor installation technology
Case 1: when paving, the cement, mortar, or adhesive on the back of the plate is too thin, the water volatilizes after paving, and a gap is formed between the adhesive and the stone, resulting in hollowing.
Situation 2: instead of painting cement on the back of the stone, the workers directly pour the cement on the ground, trowel it with a scraper, and then compact the stone. When the cement is poured on the ground, the foundation layer will be washed away, resulting in uneven distribution, and eventually uneven bonding force, and an empty drum.
Situation 3: when paving, when the work is finished, the stone on the edge of the paved place is not sealed. Cement overflow and rapid air drying will cause hollowing.

2. Insufficient pavement curing period
After paving, various bonding materials are still in the curing period of solidification, so they are eager to cross construct or put into use in advance, and the stones are easy to loosen and form hollows.
3. Temperature
When the temperature is lower than 5 ℃ during construction, the cement mortar does not fully harden, resulting in the cement mortar not reaching the due strength.
4. Materials and proportioning
The sand in the cement sand is too fine, or the mud content is too much, or the cement parameters are too few.

5. Base course treatment
① The dust and oil stain on the base course is not cleaned, resulting in the weak bonding layer, or the bonding layer is too thin and not thick enough.
② The base course is too dry, the cement slurry is not painted in place when sweeping the slurry on the ground, or it has been dried before paving the stone, resulting in insufficient adhesion between the mortar and the plain cement slurry bonding layer, resulting in hollowing.
③ The thickness between the finished stone surface and the floor base is too large, and it is easy to sink and bulge after pasting.

6. Construction process
The mortar of the bonding layer is not compacted, and the stone is not hammered and compacted after paving.
7. Maintenance
When the maintenance period is not over, people get on the vehicle, resulting in looseness and hollowing of the ground.

● Marble hollowing hazard
(1) Stone damage
If it can not be treated timely and effectively, these stone hollows will continue to expand, and fracture and fragmentation will occur under the action of external forces in use. The longer the use time, the more serious the damage to the stone.
(2) Affect seamless processing
During the overall grinding of the stone, the hollowing will also affect the seamless treatment, resulting in glue opening, black seam, water absorption, and even the fracture and breakage of the plate. As mentioned above, the problems caused by an empty drum in grinding are usually very difficult.

● Marble hollowing solution
1. Remove the marble and reinstall the marble. It is troublesome to use this method for construction, and the repair cost is large. More importantly, it is difficult to achieve the same luster, color, and pattern between the old and new marble panels after repair. If it is empty in a large area, using this method wastes time and increases the cost.
2. The epoxy resin steel bolt anchoring method is adopted. After repair, the finish is firm, erect without damage, and the construction method is simple, labor-saving, and material-saving. The construction steps are:
(1) For the hollowing stone to be repaired, determine the drilling direction and quantity, first install the cemented carbide insert with the electric drill and drill into a 5mm fine hole. It should be noted that when drilling, the drill bit should be inclined downward at an angle of 15 degrees to prevent the epoxy resin slurry from flowing out of the hole after grouting. After the hole is drilled, remove the dust in the hole with an air compressor. The ash handling air machine shall be inserted at the bottom of the hole to make all dust escape from the hole with the compressed air.

(2) Secondly, epoxy resin slurry is manufactured. Epoxy resin, dibutyl phthalate, curing agent, and cement shall be prepared according to the appropriate proportion given by stone care. When mixing, first mix the epoxy resin and dibutyl phthalate, then add the curing agent for mixing, then add the cement, mix well, and pour it into the grouting machine.
(3) The next step is grouting and anchoring. The resin filling gun shall be selected to fill the resin slurry in the hole. The gun head shall be deepened to the bottom of the hole, and the gun head shall be gradually withdrawn outward during filling. After the slurry is poured, put in the steel anchor bolt. To improve the bonding effect, the bolt shall be made into thread type, and the hexagon nut shall be screwed on one end to firmly fasten the marble slab.
(4) Before placing the bolt, to prevent the injected epoxy resin slurry from flowing out and polluting the marble surface, the hole can be blocked with lime paste first, and then the hole can be cleaned after the epoxy resin slurry is cured. Then, for the resin slurry remaining on the stone surface, use acetone or xylene to care and clean the stone in time to avoid contaminating the floor.
(5) After grouting for two to three hours, seal with white cement mortar. The color of the color paste shall be close to the surface color of the repaired stone as far as possible. After finishing the empty drum stone care construction, wait about a day, after the epoxy resin slurry on the surface dries up, you can play with it happily again.

Well, this article will be written here first. I hope it will be helpful to you. Of course, you have a better solution for stone hollowing, and we look forward to your email at sales@sntstone.com Share it with me.