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Five Things About PU Injection Grouting

Cracks are a common household problem but if left untreated, it can lead to other problems such as leakage, which can cause significant damage to your home. There are many available solutions out there to solve this issue. However, it is important to find a solution that is long-lasting and will prevent cracks from happening again. One possible option is waterproofing through PU grouting.

PU grouting, or polyurethane injection or grouting, is a waterproofing technique that injects polyurethane, a fluid resin, to prevent water leakage through cracks or gaps in the concrete of the building structures. It can be confusing because the process may be called by different names within the industry such as PU grouting, PU injection repair, PU waterproofing, PU injection grouting, but the procedure is the same.

PU grouting is an ideal solution for water leakage issues because of its short curing time, and very low cost. It has low viscosity, which allows it to expand, sealing tiny cracks to avoid further leakage. After injection, the resin also retains its flexibility, allowing subsequent movement in the structure while keeping the gaps sealed.

To fully understand the method of PU waterproofing, it is essential to first understand the causes of cracks in the first place, to give you a better idea of how PU waterproofing can help protect your home and property.

1) Cause of Cracks on Walls

To know what is the best solution for your leakage issues, it will be helpful to know what causes the cracks on your structure. There are three usual reasons behind cracks:

  • Bad Drainage
    Water is the main reason for building cracks. A bad drainage system allows water to seep through, causing building materials to become unstable and to wear away. If you plan to have PU injection grouting to repair the cracks in your property, it is also vital that you check if your drainage system is working properly.
  • Heavy Load
    In industrial areas, heavy load due to the movement of machinery and vehicles like forklift trucks and lorries can cause cracks to form on the concrete after a while. Cracks will be more severe in areas with a high volume of traffic. Structures with tin roofs can experience leaking of water onto the flooring, and this together with a heavy load may lead to cracks, holes, and gaps.
  • Wear Tear
    If the structure is not well-maintained, cracks will appear due to wear and tear that happens as the structure ages. This is especially true in areas like roofs, balconies, and other damp areas usually exposed to water and humidity.

2) Process of PU Injection Repair

Like mentioned earlier, PU grouting is one of the most recommended waterproofing techniques to solve problems of water leakage. Here are the steps on how PU waterproofing is done; though do note that this should be done by a team of specialists, with professional equipment.

  1. Cleaning
    Cleaning helps the technician to check and analyze the area and determine the location and spacing of the holes. It also removes mineral deposits left from the water leakage.
  2. Drilling
    To inject the resin into the crack, drilling is a crucial process for the injection holes. The angle while drilling should be 45 degrees or less towards around 2/3 of the structure’s thickness. There should be a 20 cm to 30 cm drilling space between the holes.
  3. Insert Packers
    The technician will place a grouting nozzle injection packer in the drilled hole. They will also tighten it with a special hexagon wrench, leaving no gap between the nozzle and drilling hole for the water to leak into.
  4. Steam Cleaning
    Using a high-pressure cleaning machine, the technician will inject clean water into the mechanical packers, at the pressure of 6Mpa, to clean the dust in the seam of the area.
  5. Sealing Cracks
    The surface of the leaking cracks is sealed with a cement-based waterproof material during the washing stage so that the polyurethane will not seep out.
  6. Grouting
    Using a high-pressure injection grouting machine, the technician will inject the polyurethane into the hole. They will elevate the grouting machine bottom-up and start injecting the resin one hole at a time.
  7. Removing the Packers
    After grouting, the grouting nozzle will be removed by the technician if there is no more leakage and will then proceed to clean up the irrigation fluid that may have spilled and solidified.
  8. Sealing
    The technician will then repair and seal the injected area of the concrete with cement-based waterproof material.
  9. Waterproofing
    To fully fortify the area, the technician will smear the grouting area with a single component waterproof material, with a 10-20 cm width and 20-30 cm length at both ends.
PU Injection process

3) Advantages of PU Injection Repair

PU grouting is only one of many possible methods of leak repairs. However, if you decide to use PU injection, you will make most of its benefits over other waterproofing techniques. Here are some advantages to this method:

  • Polyurethane is a versatile resin that can also be used for coating, maintenance, emergency repair, and insulation purposes.
  • It is a strong adhesive, which protects the concrete from building movement and exposure to sunlight, which makes it a suitable material for surfaces such as roofs and balconies.
  • It is fast drying and can seal small cracks on the surface.
  • PU injection repair comes with a low construction cost.
  • This method requires little to no maintenance.

4) Different Types of Injection Grout

Aside from Polyurethane, there are other types of grouts that you can choose. Do note that different types of grouts have specific purposes. It is important to understand the characteristics of each to make sure you are using the right type for your leak repair. Here are the other available grout options:

  • Cementitious Grouts
    Cementitious grouts are the traditional grouting material for residential applications. It is composed of cement and water, with admixes or additives, based on its purpose. If used for porous tiles (quarry, slate, or natural stone tiles), there is a possibility of this grout staining the surface.
  • Epoxy Resins
    Epoxy resin contains resin and hardener, making it less porous than cementitious grouts. It does not bond well with wet surfaces, but it adheres well to metal, concrete, and ceramics. It is a perfect choice for areas with acids and greases like the kitchen because it is strong and resistant to chemicals.
  • Acrylic Resins
    Acrylic grouts form a permanent gel, with low adhesive and compressive strength, but high tear strength. Additives can be added to the mix to hasten or prolong the reaction of it. It is the usual choice for architectural coatings and product finishes.
PU Injection grouting Singapore
PU Injection process

5) PU Grouting vs. Hacking

PU injection grouting is a hassle-free and low-cost option for cracks and leak repairs. Because it only involves inserting resin to the cracks on the concrete, there is no need to hack away your floor or walls. Hacking methods can cause further issues such as having home items covered in dust, spending money for new tiles and wall paint, and the constant noise made by the hacking process. With PU waterproofing, you will experience none of those. It is less labor-intensive, a safer method, and, most importantly, it will save you a lot of money.

Le Fong Contractor: Professional Waterproofing Company

Le Fong Singapore is one of the leading waterproofing specialists in Singapore. For 9 years, the company has built a strong clientele through its excellent waterproofing services, using advanced and innovative technologies. Le Fong also offers a no-obligatory, on-site analysis to figure out the solutions that will best suit the needs of your property.

Le Fong offers a full range of waterproofing procedures such as roof waterproofing for RC flat roofs, pitched roofs, fixed roof awnings, open balconies, wet areas (i.e. kitchens and bathrooms), as well as walls and basements.

Aside from waterproofing, the company also offers other services such as painting and coating, minor works in construction, and other general contract work, to ensure that ceiling leak will not be a problem for a long time. Le Fong is a reliable waterproofing company that delivers high-quality service every time.