What to Know About Bathroom Wall Waterproofing?

What is Bathroom Wall Waterproofing?

Bathroom wall waterproofing is applying water impervious layer on the bathroom walls up to these heights: 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.

Bathroom waterproofing is a combined process of waterproofing the bathroom floor and the bathroom walls.

How Can I Tell if My Bathroom Walls Need Waterproofing?

If your bathroom needs waterproofing, you should see these signs, such as mold and mildew growth on the walls, paint and wallcovering damage, wall structure damage, wall tile and grout damage, and any odor issues in the bathroom.

1. Mold and Mildew growth on the walls: Mold and mildew can grow on the bathroom walls, corners, and other surfaces if you do not waterproof the bathroom walls.
2. Paint and wallcovering damage: Unprotected walls can absorb moisture. This will cause peeling paint, bubbling wallpaper, or discolorations.
3. Structural damage: Water can seep into bathroom walls due to leaking. This can weaken materials, rot, and reduce the structural stability.
4. Wall tile and grout damage: Bathroom wall tiles and grout can be damaged due to heavy water leaking from the bathroom. This causes biological flux in the space and reduces the strength between the materials.
5. Odor issue: Mold and mildew can grow due to the bathroom’s water leaking. When the grown mold and mildew stagnate with bathroom water, an odor can be produced in the bathroom.

What Bathroom Wall Materials Should I Waterproof?

You should waterproof these 10 bathroom wall materials. Because these materials are not water-impervious, their seams and joints can leak water.

1. Ceramic tile
2. Porcelain tile
3. Wood
4. Natural Stone
5. Bricks
6. Burnt clay tiles
7. Concrete
8. Cork
9. Vinyl
10. Epoxy

Can I Waterproof Bathroom Walls Without Removing Tiles?

Yes, you can waterproof the bathroom walls without removing tiles. First, you should fix all the grout damage. You can use epoxy grout to seal the broken or loose grout on the bathroom wall. Then you can use epoxy waterproofing, polyurethane, or silane-siloxane-based membrane on the bathroom walls. You can use Mapei AquaDefense, Laticrete Clear Waterproofing Sealer, and Dry-Treat Stain-Proof Plus as products for the task.

How High of a Wall Should I Waterproof in the Bathroom?

You should waterproof the bathroom wall height as below

1. Shower wall splash zone height: 6 feet (183 cm)
2. Toilet wall height: 3 feet (92 cm)
3. Bathtub wall height: 2.5 feet (76 cm)
4. Sink wall height: 4 feet (122 cm)

Which Waterproofing Membranes are best for Bathroom Walls?

You can use below 8 waterproofing membranes for the bathroom wall water stops. All of these waterproofing membranes can be categorized 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.

1. Cementitious waterproofing: Cementitious waterproofing can be applied as a liquid coating on the bathroom floor and walls to stop water leaking.
2. 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.
3. Acrylic coating waterproofing: Acrylic waterproofing is a liquid waterproofing membrane that can be used for bathroom floors and walls.
4. 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.
5. EPDM Rubber waterproofing: EPDM rubber waterproofing is a sheet waterproofing membrane that can be used to waterproof bathroom shower areas, walls and floors.
6. HDPE waterproofing: HDPE is a sheet membrane waterproofing that can be used to waterproof the bathroom wall and floor.
7. PVC waterproofing: PVC is a sheet membrane waterproofing. PVC can be used to waterproof the shower area and bathroom waterproofing.
8. Polymer waterproofing: Rubber polymer can be used as positive side waterproofing for the shower areas.

How to Prepare Bathroom Wall for Waterproofing?

To prepare the bathroom wall before installing waterproofing memebrane, you should follow the below 6 guide.

1. Dry the wall completely: First, you should keep the wall dry for at least 24 hours, using ventilation or heaters, until no surface moisture remains on the bathroom wall surface.
2. Clean thoroughly: Then you should scrub off soap scum, grease, and dirt with an alkaline cleaner. Then rinse well, and let the walls dry.
3. Remove loose material: Next, you should scrape away any peeling paint, hollow grout, or loose tiles on the bathroom wall. This helps to bond the coating to the solid wall surface only.
4. Repair grout and caulk: Then you should fill missing grout lines and replace damaged silicone in corners and edges on the bathroom walls to block moisture entry points.
5. Sand glossy finishes: You should lightly scuff shiny tile or paint to improve adhesion for primers or waterproof coatings on the bathroom walls.
6. Prime the surface: You should apply a compatible primer according to your bathroom wall type, such as tile, cement board, or plaster, to improve bonding.

After preparing the bathroom wall for waterproofing, you should install a waterproofing membrane on the bathroom walls.

How to Install Waterproofing Membrane on Bathroom Walls?

To install a waterproofing membrane on the bathroom walls, you should follow the step-by-step guide.

1. Apply the first layer of waterproofing membrane on the bathroom walls.

• Liquid membrane: To apply a liquid waterproofing membrane on bathroom walls, you can use a roller, brush, or sprayer. The coating thickness should be 0.5-0.6 mm WFT (20-24 mil). Waterproofing coverage should be 0.35-0.55 L/m² (0.09-0.14 gal/100 ft²).
• Sheet membrane: To apply sheet waterproofing membrane on bathroom walls, you should spread thinset or approved adhesive with a 3-4 mm (1/8-3/16 in) notched trowel. The sheet should be embedded firmly and rolled from the center outward to remove all trapped air.

2. Seal seams and overlaps of the waterproofing membrane on the bathroom walls.

• Liquid membrane: To treat seams, you should embed fabric tape on all corners, seams, and around penetrations while the first coat is still wet.
• Sheet membrane: To treat seams, you should overlap sheets by 50-100 mm (2-4 in), roll them tight with a J-roller, and seal edges according to the manufacturer’s instructions. If a seam lifts, you should re-adhere it immediately.

3. Apply a second layer of waterproofing membrane on the bathroom walls

• Liquid membrane: To build final thickness, you should apply a second coat perpendicular to the first after 1-2 hours or when the first coat is uniform and non-tacky. The total thickness should be 0.8-1.2 mm WFT (32-48 mil), giving 0.5-1.0 mm DFT (20-40 mil).
• Sheet membrane: To build the final thickness, you should patch all fastener heads (if used) and add banding at shelves and niches. Keep substrate/air temperature between 10-32 °C (50-90 °F) and at least 3 °C (5 °F) above dew point.

4. Let the Bathroom Wall Waterproofing Membrane Cure and Dry

To cure the waterproofing membrane on the bathroom walls, you should allow 12-24 hours (check product label). Perform a 10-minute spray test. If no dark spots or seam failures appear, you should begin tiling according to the ANSI A118.4/A118.15.

Can I Waterproof the Existing Bathroom Wall?

Yes, you can waterproof the existing bathroom walls by using waterproofing sealers and paints, epoxy grouting, and silicone caulk. Before applying any waterproofing agent on the bathroom’s existing walls, you should thoroughly clean them to remove mold and mildew and repair any cracks or damage to the walls.

After applying the waterproofing on the walls, you should improve the proper ventilation and prevent excessive humidity in the bathroom to prevent moisture-related issues to the walls.

Read More: How to Waterproof a Bathroom Wall?

Is the Shower Attached Wall Need Waterproofing?

The shower attached wall should be waterproof up to 6 feet (183 cm) because an open shower can spread the water to the wall heavily. Therefore, the mounted wall is the heavy water-damaged wall in the bathroom.

How to Damage a Bathroom Wall Waterproofing?

Bathroom wall waterproofing can be damaged due to these 5 common reasons. A damaged waterproofing coating of the bathroom wall can penetrate the water inside the structure and it cause to water related issues to the structure.

1. Improper installation: If the bathroom wall waterproofing is not installed properly, it can be damaged easily. Improper bathroom wall waterproofing is using the wrong waterproofing membrane, laying with a thinner thickness, applying fewer coatings, not following the manufacturer’s guidelines, and using non-skilled labor.
2. Physical damage: Bathroom wall waterproofing sealant can be damaged when the wall is hit by something, as it can damage to inside of the substrate.
3. Chemical damage: The bathroom wall waterproofing layer can be damaged due to using harsh chemicals while cleaning.
4. Temperature fluctuation: Due to temperature fluctuations, the structure can expand and contract. As a result, the waterproofing layer on the bathroom wall can be damaged easily.
5. Water pressure: High water pressure leakage can cause to damage the waterproofing layer.

How to Protect Bathroom Wall Waterproofing?

A bathroom wall can be protected by following the 6 steps below.

1. Proper waterproof installation: You should use the recommended waterproofing membrane and product with skilled labour for the proper waterproofing installations for the durable waterproofing coating on the bathroom walls.
2. Avoid physical damage: Do not let to drill, cut, or nail into the bathroom walls because this can damage the waterproofing membrane.
3. Use mild cleaning agents: You should use mild cleaning agents instead of harsh chemicals to clean the bathroom floor.
4. Control the temperature: Do not let too much dry and wet the bathroom floor, which causes temperature fluctuations.
5. Do regular maintenance: You should check for regular maintenance and repairs for the bathroom. You should observe cracks, tears, and loose materials in the joints and do immediate repairs.
6. Use a sealant: You can use a sealant above the bathroom wall materials. This will prevent the water from penetrating the walls.

How to Use a Bathroom Without Waterproofing Walls?

You can use a bathroom without waterproofing the walls using the following methods:

1. Use shower stalls: Shower stalls do not allow water to spread on the bathroom walls. Hence, when you use a bathroom stall, you should not do bathroom waterproofing.
2. Use shower curtains or doors: Shower curtain or doors allows the accumulation of water in the bathtub areas without spreading over the walls. This will prevent the water from leaking through the walls.
3. Using a bathmat: Place a bathmat near the bathtub area. This will prevent water from being tracked across the bathroom floor and reduce the chance of water reaching the walls.
4. Avoid overflowing the bathtub: Do not allow to overflow the bathtub area, as walls can seep water.
5. Do a quick cleanup: You can wipe down the wet surfaces when the water splashes on the wall.