When I visited the local home improvement after-sales market, I found that the root cause of more than 60% of second-hand house repairs and after-sales complaints of new houses was not the poor skills of the construction masters, but the wrong selection of waterproof building materials in the early stage.
Many owners fall into a misunderstanding: they think that waterproofing can be solved once and for all by just applying a few more coats of paint. They ignore the material suitability, aging resistance and environmental protection properties of the building materials themselves. Eventually, problems such as moisture on the walls, water seepage in the bathroom, and peeling of the exterior walls appear after two or three years of moving in.
Nowadays, with rainy weather becoming the norm and high-rise exterior facades having large temperature differences, waterproof building materials are no longer just leftovers for home decoration, but the core materials that protect the service life of the house.
There are many categories of waterproof building materials circulating on the market. It is easy for laymen to be misled by businessmen’s words. They all seem to be waterproof materials. Their applicable scenarios, service life, and construction conditions are very different.
The most commonly used flexible waterproof coating for daily home decoration is also the current mainstream choice for kitchen and bathroom spaces. This type of building material contains highly elastic acrylic emulsion, which can expand and contract along with the fine cracks in the wall.
After the house is moved in, slight settlement of the foundation and thermal expansion and contraction of the wall will produce fine lines within 0.2 mm. Ordinary rigid waterproof coatings have high hardness and no ductility, and will directly lose the waterproofing effect as the wall cracks. Flexible coatings can firmly adhere to the base surface and block small water seepage channels. This is the core reason why kitchen and bathroom walls must be flexible waterproof.
Rigid waterproof building materials, as opposed to flexible coatings, also have irreplaceable use scenarios and are not inferior products.
Rigid waterproofing is represented by cement-based penetrating crystalline materials, which rely on active chemicals to penetrate into the concrete and react with the concrete to crystallize, blocking capillary pores from the inside.
This type of building material has no elasticity and cannot cope with wall deformation, but it is extremely resistant to pressure, wear, and blisters. It is suitable for basement floors, balcony floors, and exterior wall concrete bases.
Many decoration companies use flexible waterproofing for the whole house to save trouble, but this will cause the waterproof layer on the ground to bulge and the ceramic tiles to hollow out later. The essence is a mismatch between building materials and construction scenes.
In addition to coating waterproofing, the usage rate of rolled waterproof building materials in self-built houses and penthouse decoration has continued to increase in the past two years.
Modified asphalt waterproofing membranes and polymer polypropylene membranes rely on a fully fitted and seamless overlapping structure. Their waterproofing integrity far exceeds that of brush-type coatings, and they can withstand heavy rains and long-term erosion.
Rooftop residents face water accumulation, temperature differences and exposure to the sun all year round. Brush-type waterproofing will cause powdering and peeling off after three to five years. The membrane’s UV resistance and anti-aging lifespan can generally reach more than 15 years.
However, the roll material has extremely high requirements for the flatness of the base surface. It cannot be cut and fitted in the small indoor kitchen and bathroom space. Blind use will cause leakage at the corners. It needs to be rationally selected based on the size of the space.
The biggest chaos in the current waterproof building materials industry is that low-priced non-standard products flood the sinking market.
Many off-brand waterproof building materials focus on low prices and high volume. They reduce raw material costs by overfilling talc powder. When tested, the short-term waterproofing data meets the standard, but they will hydrolyze and pulverize within half a year.
Even more hidden are the potential environmental risks. Inferior solvent-based waterproof coatings will leave benzene and free formaldehyde residues. Water vapor circulates quickly in closed bathrooms, and harmful substances will continue to volatilize, affecting indoor air quality in the long term.
In accordance with the national standard GB 18583-2008 mandatory standard for home decoration waterproofing, all indoor waterproof materials must meet the water-based environmental protection level. There is no need to delve into complex parameters when purchasing. You only need to verify the two qualifications of ten-ring environmental protection certification and water-based labeling to avoid 90% of inferior products.
There is another detail that is easily overlooked by everyone: the supporting auxiliary materials of waterproof building materials determine the final waterproof limit.
Nodal leakage cannot be solved by relying solely on the main materials. The roots of pipes, yin and yang corners, and the periphery of floor drains are areas with high risk of leakage in the whole house. These locations need to be strengthened with waterproof leak-proofing paste and mesh cloth.
Many owners only focus on the unit price of waterproof coatings, compress the budget for auxiliary materials, and use ordinary cement mortar to replace the waterproof reinforcement layer. In the later period, 90% of local leaks will occur in these corner nodes.
A high-quality waterproofing system is never a single material, but a combination of main materials, reinforcing auxiliary materials, and base surface treatment.
From the perspective of industry development trends, waterproof building materials are transforming towards long-term, green and lightweight.
In the past, heavy asphalt membranes have been gradually replaced by lightweight polymer membranes, which not only have no odor during construction, but can also be adapted to prefabricated decoration base surfaces; self-healing waterproof coatings have become popular, and the materials have microcapsules inside. When new fine lines appear on the wall, the waterproof colloid can be automatically released to seal the gaps, greatly reducing the cost of later repairs.
For ordinary homeowners, there is no need to chase cutting-edge new materials and adhere to the three principles of “scene matching, national standard compliance, and complete supporting facilities” to eliminate 99% of home decoration leakage problems.
House waterproofing is never a one-time construction task, but a systematic project that prioritizes materials.
Instead of worrying about how many times the construction should be painted and how long the water closure test should be done, we should first distinguish the categories of building materials according to the kitchen and bathroom, exterior walls, roofs, and basements, screen out non-standard and inferior products, and make up for the shortcomings of node auxiliary materials. Only in this way can we avoid repeated brick smashing and repair, and save subsequent high maintenance costs.
