Are you noticing moisture in or near your shower long after you’ve finished using it, when the area should be completely dry?
Does your bathroom always have a musty smell? Do you notice discoloration of porous surfaces? Are you having a hard time preventing mold and mildew growth around your shower?
Before you descend into nightmarish fears about a full demo and reinstallation of your tile shower, understand that there are several potential causes that should be ruled out. The details in this article may help you to identify the real source of the moisture problem in your bathroom.
The Science of Moisture in Building Materials
First, let’s take a look at how water and moisture vapors make their way into building materials. Many of the materials used in bathrooms are porous: wood framing, plywood, cement, thinset, natural stone, certain types of tile, grout, drywall, cabinetry, and more. These porous materials can absorb moisture if it has nowhere else to go. The two main ways this happens are through gravity and capillary action.
Most people are already familiar with how gravity moves water, because we can see it with our own eyes. You turn on the faucet and watch the water go down the drain. You spill water and watch it flow to the lowest point. Water can also move through microscopic cracks or gaps between tiles, grout lines, around drains, or where a floor meets a wall. It doesn’t need a big opening to get in. Even a hairline crack is enough space to allow water to travel.
Capillary action is when water moves through a narrow space because of the way molecules attract. It doesn’t need gravity at all, and it can even work against gravity. When you suck a drink through a straw or use a paper towel to soak up a spill, you are creating capillary action. When a porous material is exposed to water, the moisture can travel up through materials to fill the tiny holes (pores) in the material. This is capillary action.
Even sealed tile, grout, or other porous surfaces can be susceptible to water penetration. How? Water vapor. The tiny, invisible droplets floating through the air can pass right through sealers. With the high humidity typical in a bathroom environment some water, in the form of vapor, inevitably settles into building materials. If that moisture can escape, no worries. If it can’t, then you’ll need to figure out why and do something to resolve the problem.
Ideally, building materials are selected carefully, installed correctly, and maintained well so that water either can’t get where it’s not supposed to go or there are plenty of ways for it to escape. With a clearer understanding of how water and moisture vapor can seep into materials, let’s take a look at how things don’t always go as planned.
Plumbing
Common plumbing problems that can lead to leaks and moisture damage include old, corroded pipes, improperly installed plumbing, and damage to plumbing. Even water, itself, can cause problems with pipes.
Old, Corroded Pipes
Have you ever had a chip on your car windshield? A seemingly insignificant little chip can eventually become a large crack that threatens the structural integrity of a windshield. Similarly, a bit of corrosion on a pipe can result in a full-blown leak. It may not happen all at once. It may start with a pinhole leak that slowly seeps into building materials, resulting in mold and mildew. Left unchecked, this leak could cause structural issues.
If your home is new or recently replumbed, you won’t need to worry about corrosion issues, but even new pipes can leak.
Improper Installation
Well-installed pipes and connections efficiently redirect water flow from your bathroom to your septic or the sewer system. If you suspect there is a leak in your new plumbing, reach out to a plumber with a strong professional reputation. They can examine your plumbing to be sure everything is tightly sealed and properly installed and repair any issues they might discover.
Hard Water
Hard water contains a lot of calcium, magnesium, and other minerals. In areas frequently exposed to water, such as showers, tile can become white or chalky in appearance. In homes with especially mineral-rich water, scaly deposits may build up. If you see these problems on your tile, chances are those same problems are happening inside of your pipes. Read our article, Hard Water, Water Softeners, and Your New Tile to learn more about improving your water quality. If slow leaks, worn seals, pipe malfunctions, or other issues have already started, then you’ll need to hire a plumber.
Blocked Drains and Overflow
There’s no shame in a shower becoming messy. That’s what happens when we use it for its intended purpose. Shampoo, conditioner, shaving cream, and soap can all leave behind residues. And then there’s the human stuff, like skin cells, body oils, and hair. All these things can lead to plumbing blockages where water has nowhere to go or drains too slowly. The resulting water overflow can cause moisture problems.
Use screens or strainers over your bathroom drains to prevent blockages.
One earth-friendly DIY solution for an existing blockage is to pour baking soda and vinegar in the drain and cover. Allow it to sit for 15-30 minutes and then flush with boiling water. NOTE: If you have a calcium-based natural stone, such as marble, this method is not advisable, as it could result in acid etch damage on your tiles.
Control Moisture
The most important thing you can do to keep your shower clean and free of mold and mildew is to control the amount of moisture that remains after showering. Mold and mildew thrive in a wet environment. Keep your bathroom as dry as possible so that it will be inhospitable to fungi. Following simple tile cleaning tips can help maintain your shower and prevent moisture-related problems.
- Keep a squeegee in your shower. After each use, swipe the shower walls and glass with the rubber blade. This is a quick and easy way to redirect water from the walls to the drain.
- Use a microfiber cloth to dry any excess water that remains after using the squeegee. Not only will this reduce moisture, it will help prevent water spots and soap scum buildup.
- Adequately ventilate your bathroom to prevent post-shower humidity in the air from settling on the shower tile you just dried. Make sure that your bathroom ventilation fan is the right size for your bathroom.
- Remove wet towels, wash cloths, floor mats, and other wet items from the bathroom.
- Radiant underfloor heating can help dry out the moisture. Many clients ask whether it is possible and safe to install heating under shower floors. The answers are yes and yes!
- If you live in a busy household with an often-used shower, run a dehumidifier in your bathroom.
- A clogged shower drain can cause slow drainage or puddling of water. Remove hair and debris from the drain. If necessary, remove the drain cover or snake the drain.
Tile Installation and Waterproofing
Improper tile installation can result in a shower failure. Here are signs to look for. If your tile is natural stone you may notice rust, discoloration, flaking, small holes (pitting), or peeling layers (spalling). If you have less permeable tile, you may simply notice problems with the grout lines, but the integrity of the bonding materials will be compromised and things will start falling apart.
Waterproofing in a tile shower is crucial to preventing moisture problems in your bathroom. Installers at Copher Tile and Stone use a vapor barrier to reduce the rate of moisture movement through building materials. We follow industry and manufacturer’s standards and guidelines. We flood test our showers.
Choosing the right shower drainage system can make a big difference in long-term performance and moisture control.
Moisture problems in and around your shower may be easily resolved or require professional services. If you have moisture problems or notice signs of water damage or leaking, be sure to take meaningful steps to prevent long-term damage right away. When it comes to water and moisture mitigation, time is of the essence.
Frequently Asked Questions
1. Why do I still see moisture in my shower after using it?
If moisture lingers in your shower, it is often caused by poor ventilation, hidden leaks, or water trapped in porous materials like grout or tile. Over time, this trapped moisture can lead to mold, mildew, and discoloration if not properly addressed.
2. What are the most common causes of bathroom moisture problems?
The most common causes include plumbing leaks, blocked drains, improper waterproofing, and high indoor humidity levels. In some cases, even normal shower steam can settle into building materials and create long-term moisture issues.
3. How can I prevent moisture buildup and mold in my bathroom?
Proper ventilation, drying surfaces after showering, and regular maintenance of drains and grout are key to preventing moisture buildup. Using a squeegee, running an exhaust fan, and controlling humidity levels can significantly reduce mold and mildew growth.
Conclusion
Reference: Fred Hueston Interviews Foster Lyons on Moisture Discoloration
by Alice Dean
Copher Tile & Stone proudly stays up to date on tile installation with ongoing education with Mapei Technical Institute, Ardex Academy, the National Tile Contractors Association, Laticrete, and Schluter. Copher is a Certified Tile Installer (#1644).
