Want to make your bathroom as water-resistant as possible? Proper waterproofing is essential to prevent leaks, mildew, and other water damage. Follow these 10 tips to help waterproof your bathroom and keep it looking great for years to come.
Use Water-Resistant Drywall and Cement Board
When remodeling or building a bathroom, use moisture-resistant drywall and cement board. Materials like DensShield and Hardybacker are designed for high-humidity areas like bathrooms. They resist warping and deterioration better than regular drywall. Apply waterproofing membranes over cement board seams for extra protection.
Install a Waterproof Membrane
Installing a waterproofing membrane behind bathroom tiles is one of the most important waterproofing steps. Membranes like RedGard and Kerdi create a waterproof barrier that prevents leaks from reaching framing and drywall behind the tiles. Apply membrane on walls and floors, sealing seams and edges thoroughly.
Choose Water-Resistant Paint
On bathroom walls without tile, choose mold-resistant paints like Zinsser Perma-White. Avoid flat paints, which absorb more moisture. Eggshell or semi-gloss paints with mold/mildew resistance provide a scrubbable, water-repellent finish. Prime surfaces before painting for better protection.
Caulk Thoroughly
Caulking seals gaps where water could seep through. Carefully caulk inside and around the tub, shower, sink, toilet, windows and any joints or seams. Use a bathroom caulk like GE Silicone II that stays flexible and resists mold growth. Re-apply caulk annually or whenever cracks appear.
Install a Waterproof Floor
Tile, vinyl and linoleum bathroom floors should have a waterproof underlayment such as Schluter Ditra. This underlayment waterproofs the floor and uncouples the floor from subfloor movement. Make sure flooring and adhesives are suitable for bathrooms. Avoid regular plywood subfloors which can warp over time.
Choose Water-Resistant Fixtures
Choose faucets, toilets and other fixtures made to withstand moisture. Look for tub and shower valves with scald protection. Seek metal fixtures rather than plastic or particleboard. Use mold-resistant silicone caulk around sinks, toilets, tubs and showers. Make sure bathroom ventilation adequately removes moisture.
Install a Waterproof Tub/Shower Surround
Factory-made surrounds like Swanstone paneling provide a waterproof, seamless alternative to tile. Ensure panels fully seal tub/shower edges. If using tile, install a waterproofing membrane beneath it and apply waterproof grout. A glass surround is also very water-resistant. Make sure the tub or shower pan has proper drainage.
Slope Floors to Drain
Ensure bathroom floors slope properly to drains. A 1/4-inch per foot slope is recommended. Use a level during flooring installation to maintain the right slant. This prevents “ponding” where water pools on the floor. Check flooring joints for flat spots. Fill any low areas with floor leveler compound.
Upgrade Door and Window Seals
Seal bathroom door jambs with high-quality weatherstripping to block moisture from escaping. Ensure doors fully shut. Use sweep seals for gaps at the bottom. Apply silicone caulk around windows and use mold-resistant window casing. Keep exhaust fans running for a while after baths and showers.
Maintain Caulking and Grout
Even with proper waterproofing, sealants deteriorate over time. Check caulk and grout periodically for gaps that allow water through. Re-apply caulk around fixtures and joints when needed. Re-grout tile and use grout sealer to keep grout water-resistant. Catch issues early before moisture gets behind walls.
FAQs About Waterproofing Your Bathroom
Here are answers to some frequently asked questions about waterproofing bathrooms:
How long does bathroom waterproofing last?
With proper installation and maintenance, quality waterproofing should last at least 5-10 years, sometimes longer. Check caulk, grout and seals annually for deterioration and reapply as needed. Some waterproofing membranes can last 20+ years before needing replacement.
Does painting bathroom walls help waterproof them?
Yes, mold-resistant paints provide some degree of waterproofing by creating a washable, water-repellent layer on bathroom walls and ceilings. But paint alone is not enough—install backerboard and apply a membrane first for full protection.
Do I need to waterproof the floor and walls?
It’s best to waterproof all bathroom surfaces, including floors, walls and the base of tub/shower areas. Membranes under floor tiles and on walls prevent moisture from seeping through to vulnerable framing and drywall. Waterproof tub surrounds also help.
Should I use a bathroom exhaust fan to help?
Proper ventilation is important to remove humid air and prevent moisture buildup. Run exhaust fans for a half hour or more after bathing. Make sure fans are ducted outside, not just recirculated into attic spaces. Ventilation helps, but does not replace waterproofing.
What are signs I need to re-waterproof surfaces?
Look for deteriorating caulk and grout, moisture on walls and ceilings, musty odors, peeling paint or tiles, cracks around fixtures, or any evidence of leaks. Catch problems early before major damage occurs behind walls. Re-waterproof as needed.
How do I maintain waterproof surfaces long-term?
Check caulk and grout annually and re-apply as needed. Verify floor slopes are intact and drain properly. Watch for cracks at joints or seams in tub surrounds. Repaint wall surfaces for continued water repellency. Get any leaks fixed immediately before damage spreads.
Conclusion
Waterproofing your bathroom thoroughly is crucial to prevent costly water damage and mold growth down the road. Following these tips during bathroom remodeling and using high-quality waterproof membranes, sealants, caulk and paint will keep your bathroom protected. Be diligent about ongoing maintenance and catch issues quickly to maintain a leak-free space. With proper installation and care, your bathroom can stay water-resistant for years before any waterproofing updates are needed.