What to Know About Bathroom Waterproofing: Floor, Walls and Fixtures

Written By Adam Paul - Waterproofing Expert

Bathroom waterproofing is applying waterproofing membrane on the bathroom floor, walls, shower, toilet area and fixtures to prevent water from leaking into the building structure. You can detect bathroom water leaking by mold and mildew growth, wet bathroom wall surface, visual inspection, water dripping sound, and inspection by water detectors and bills.

A water-damaged bathroom raises these 5 major problems such as mold and mildew growth on the walls, paint peeling and wallcovering damages, structural damages, tile and grout damages, loosening materials, and odor issues. In order to prevent water from leaking and avoid these water problems, you should waterproof the bathroom floor, walls, shower, and fixtures.

You can use liquid waterproofing membranes and sheet waterproofing membranes for bathroom waterproofing. You can use cementitious waterproofing, epoxy waterproofing, acrylic, bituminous, EPDM, HDPE, PVC waterproofing and polymer waterproofing for bathroom waterproofing methods. After applying the bathroom waterproofing, it should be cured for 2 to 24 hours without exposure to water.

You should waterproof the bathroom floor, walls, shower, window, ceiling, tiles, subfloor cabinets, and cladding. A waterproof bathroom can be damaged due to construction activities and human activities. You can protect a waterproofed bathroom by avoiding using harsh chemicals, selecting proper quality materials, using expert knowledge, following the proper manufacturer’s guidelines, and doing proper maintenance and repairs regularly.

When waterproofing a bathroom, you should waterproof the bathroom floor before tiling because grout line can leak the water. Also, you should waterproof tiled bathroom walls in order to prevent water damage from spreading on the bathroom walls due to the shower and bathtub. You should waterproof all the bathrooms in order to protect them from water, humidity, and moisture.

What is Bathroom Waterproofing?

Bathroom waterproofing is applying waterproofing membrane on the bathroom floor, walls, shower, toilet area and fixtures in order to prevent water from leaking into the building structure. Bathroom waterproofing requires a well-prepared, dust and debris-free surface with applying a suitable primer or sealant. After waterproofing is applied surface should be cured for 2 to 24 hours without exposing water.

A waterproof bathroom does not seep the water through the floor and walls. This will prevent moisture damage, mold and mildew growth on the bathroom floor, walls and ceiling. There are two main types of bathroom waterproofing membranes: liquid membrane and sheet membrane. Liquid membranes are easy to apply on the bathroom wall and floor surfaces, while sheet membranes are complex. Before applying the waterproofing membrane, you should detect bathroom water leaking as follows.

How to Detect Bathroom Water Leaking?

You can detect bathroom water leaking by observing these five signs: visual inspection, mold and mildew growth, water dripping sound, wet wall surfaces, and inspecting water detectors and bills. These 5 signs will show you whether your bathroom is water leaking.

Mold and mildew growth: Mold and mildew growth can be seen on the bathroom wall surface and corner of the walls.
Wet wall surface: If your bathroom water is leaking, you can observe the closed walls are getting wet. You can check this by touching your fingers.
Visual inspection: Look for water stains on walls or ceilings beneath the bathroom and inspect the floor around the toilet, shower, bathtub, and sink for any water leaking.
Water dripping sound: Bathroom water leaking can be observed by dripping sounds. You can hear dripping sounds on the wettest days.
Inspecting by water detectors and bills: You can detect heavy bathroom water leaking by using water detectors and water bills.

What Are the 5 Common Problems if You Don’t Waterproof Your Bathroom?

If you do not waterproof your bathroom properly, you can observe the below five common problems.

Mold and mildew growth: Mold and mildew can grow on the bathroom walls, surfaces, ceilings, and corners, which causes health problems and affects aesthetic appeal.
Paint and wallcovering damage: Unprotected walls can absorb moisture. This will cause peeling paint, bubbling wallpaper, or discolorations in the bathroom.
Structural damage: Used water in the bathroom can be seeped into walls, floor, and ceiling. This can weaken materials, rot and reduce the structural stability.
Tile and grout damage: Water in the bathroom can penetrate through improperly sealed tiles and grout. This causes biological flux in the space and reduces the strength between the materials.
Odor issue: Mold and mildew can grow due to the bathroom leaking. When the grown mold and mildew stagnate with bathroom water, odor can be produced in the bathroom.

What are the Waterproofing Membranes for Bathroom Waterproofing?

You can use below 8 waterproofing membranes for bathroom water stops. All of these waterproofing membranes can be categorised into liquid and sheet membranes. Liquid waterproofing membranes are suitable for uneven surfaces, floors, and walls, while sheet waterproofing membranes are suitable for bathroom floor waterproofing.

Cementitious waterproofing: Cementitious waterproofing can be applied as a liquid coating on the bathroom floor and walls to stop water leaking.
Epoxy waterproofing: Epoxy waterproofing is an impermiable, liquid waterproofing membrane that can be used on the bathroom floor and walls. Epoxy can be used for old bathroom water stops also.
Acrylic coating waterproofing: Acrylic waterproofing is a liquid waterproofing membrane that can be used for bathroom floors and walls.
Bituminous coating waterproofing: Bituminous coating waterproofing is a liquid waterproofing membrane that can be used for both bathroom walls and floors to prevent water leaking.
EPDM Rubber waterproofing: EPDM rubber waterproofing is a sheet waterproofing membrane that can be used to waterproof bathroom shower areas, walls and floors.
HDPE waterproofing: HDPE is a sheet membrane waterproofing that can be used for bathroom wall and floor waterproofing.
PVC waterproofing: PVC is a sheet membrane waterproofing. PVC can be used to waterproof the shower area and bathroom waterproofing.
Polymer waterproofing: Rubber polymer can be used as positive side waterproofing for the shower areas.

What Bathroom Areas You Should Waterproof?

You should waterproof all over the bathroom floor area, 6 feet (183 cm) height splash zones in the shower wall, 3 feet (92 cm) height at the toilet wall, 2.5 feet (76 cm) height at the bathtub floor, and 4 feet (122 cm) height at the sink wall.

You should waterproof the bathroom shower, window, ceiling, tiles surface, subfloor, cabinet and cladding for higher water protection.

Bathroom Floor Waterproofing

You should waterproof all over the bathroom floor (above the substrate) to prevent water seepage to the building structure. You should waterproof the bathroom floor when you see mold and mildew growth, paint and wall covering damage, structural damage and tile and grout damage. You should waterproof the substrate before applying bathroom flooring such as tile, wood, stone, brick, burnt tile, concrete, cork, vinyl, laminate flooring, rubber flooring and epoxy flooring. You have to spend between $750 to $2000 cost for waterproofing 6 × 10 feet bathroom area.

You can reduce that cost if you do it yourself, choosing cost-effective materials, applying a basic waterproofing system, using sealants and paint options, doing regular maintenance and contacting the local suppliers. A waterproofing layer is lasts long about 10 to 15 years, but it can improve with the proper maintenance and repairs. A waterproof bathroom is stain-resistant if the flooring is resistant to stains. By applying sealant, waterproof paint and epoxy, you can waterproof existing bathroom floor tile.

Bathroom Wall Waterproofing

Bathroom wall waterproofing is essential for stopping water seeping through the walls in the bathroom. Bathroom walls get wet by the spread water from the shower, bathtub and faucet. This spread water can damage the walls and structure after seeping.

In order to prevent bathroom water damage, you can use waterproof drywalls instead of regular drywall, and you can use a waterproof membrane in the bathroom. You can seal the gaps and joints, apply waterproofing paints, install tiles with waterproof grouts, improve the ventilation, install a waterproof backer board around the shower and tub surface, and use curtains in the bathing area.

Bathroom Shower Waterproofing

Bathroom shower waterproofing is installing a waterproof membrane on the shower floor and walls to prevent water from seeping into the structure. You should waterproof 6 feet height on the shower walls and below floor area, shower pan or base, seams and joints, shower niche and shel in order to prevent water leaking from the shower and walls.

Bathroom Window Waterproofing

Bathroom window waterproofing is a process of creating a water-tight seal around and in the window to prevent water infiltration to the bathroom walls and structure. Mold and mildew growth, rot decay and energy efficiency issues are the major water problems for the bathroom windows. In order to waterproof bathroom windows you can seal joints and gaps, install weather stripping, install window stripes, window flashing, waterproofing paints, and do regular maintenance properly.

Bathroom Ceiling Waterproofing

Bathroom ceiling waterproofing is the process of applying a protective coating on the ceiling surfaces in a bathroom to prevent water damage, moisture penetration, and the growth of mold and mildew. Bathroom ceiling waterproofing can be done by using moisture-resistant drywall, green board, cement board, waterproof paint, improving the bathroom ventilation, reducing the humidity level, and installing a vapour barrier to prevent moisture.

Bathroom Tile Waterproofing

Bathroom tile waterproofing is applying waterproof membranes on the tiles to make them resistant to water. Bathroom tile waterproofing can prevent water damage on the tiles, such as discolouration, staining, mold growth, tile loosening, and structural damage to the floor or walls beneath the tiles.

You can use a variety of waterproofing methods to protect your bathroom tiles, including applying waterproofing membranes, sealants, grouts, or epoxy coatings. You can enhance the waterproofing capability of the bathroom tiles by doing regular cleaning, resealing the grout lines and installing waterproof backer boards.

Bathroom Subfloor Waterproofing

Bathroom subfloor waterproofing is applying a waterproofing membrane on the subfloor in a bathroom to make it resistant to water. Bathroom subfloor waterproofing can prevent water damage such as warping, rotting, mold growth, and structural damage to the floor and the underlying structure.

You can use waterproof membranes or barriers, sealants, waterproof cement boards, and water-resistant plywood in order to prevent water leaking from the subfloor. Additionally, you can apply a waterproof paint or install a waterproof underlayment or padding beneath the flooring material for extra water protection.

Bathroom Cabinet Waterproofing

Bathroom cabinet waterproofing is applying specific treatments or methods to the cabinets in a bathroom to make them resistant to water. Bathroom cabinet waterproofing is important to prevent water damage such as warping, discolouration, paint peeling, and mold growth on the cabinet.

You can protect bathroom cabinets from water by applying sealants or varnishes, waterproof paint, PVC, and stainless steel wrapping for the cabinets. You can apply waterproof paint, lacquers, vinyl or plastic liners for wooden cabinets to protect them from moisture.

Bathroom Cladding Waterproofing

Bathroom cladding waterproofing is the process of applying waterproof treatments or techniques to the cladding in a bathroom to make it resistant to water. This is essential to prevent water damage, such as discolouration, mold growth, blistering, and structural damage to the walls.

You can use waterproofing sealants, paints, and waterproofing membranes to prevent cladding water damage. Water-resistant cladding materials such as PVC, vinyl, or ceramic tiles can improve the waterproofing capability of the bathroom cladding. You should maintain, clean, and reseal the cladding to enhance the waterproof quality and prevent water damage.

How to Damage Bathroom Waterproofing Coating?

Bathroom waterproof coating can be damaged due to construction activities and user activities. You should know the below 9 bathroom waterproofing damages in order to prevent them for better waterproof coating efficiency.

Using the wrong membrane for bathroom waterproofing
Cutting and drilling on the bathroom surface after installing waterproofing coating on the bathroom.
Improper knowledge of bathroom waterproofing
Not using quality materials for bathroom waterproofing.
Not following the manufacturer guidelines for bathroom waterproofing
Using harsh chemicals inside the bathroom
Lack of bathroom maintenance
Temperature fluctuation in the bathroom area
Structure settlement

How to Protect Bathroom Waterproofing Coating?

Bathroom waterproof coating can be protected by following proper methods and usage. The bathroom waterproofing layer should be protected from physical damage and chemical damage. You should follow the below steps to protect the bathroom waterproofing membrane and improve the service life of the waterproofing layer.

Avoid using harsh chemicals in the bathroom
Select proper, quality materials for bathroom waterproofing
Use expert knowledge for waterproofing and installation.
Follow the correct manufacturer guidelines for bathroom waterproofing.
Maintenance and repair of the bathroom properly
Use waterproofing membranes that resist to temperature fluctuation.

Can I use Tiles for Bathroom Floor Waterproofing?

No, you can’t use only tiles as a waterproofing layer for high-water impact areas like bathrooms because water can leak through the grout lines and seep into the structure. Therefore you should waterproof the bathroom floor before installing tile in order to have higher protection from the water. You should waterproof the bathroom floor using a sheet membrane or liquid membrane for better results.

Should I Waterproof a Tiled Bathroom Walls?

Yes, you should waterproof tiled bathroom walls in order to prevent water damage from spreading on the bathroom walls due to the shower and bathtub. Tile bathroom walls can seep the water from the grout lines. Hence, you should use waterproof coating or epoxy on the tile surface to waterproof the bathroom walls.

Is Waterproofing Necessary for All Bathroom Showers?

Yes, waterproofing is necessary for all bathroom showers. This is because showers are consistently exposed to water and humidity. Without proper waterproofing, water can seep into the walls, floors, and other structures, leading to issues like mold growth, structural damage, and unsightly water stains. Therefore, you should waterproof the bathroom shower to maintain integrity and longevity.