Flooded tile installations have been top-of-mind lately given two extreme hurricanes within two weeks. In anticipation of questions, we're pooling together advice about how commonly dry area tile installations act as a submerged swimming pool-like installation for a period of time.
Since we don't have all the answers, we anticipate this article being a work-in-progress. As we come upon new information, Robb Roderick CTI #727 and Mark Heinlein CTI #1112 - both National Tile Contractors Association trainers - and I will add to this discussion.
Immediate concerns when a home is flooded
Perhaps the biggest concern when flood waters take over your home is how dirty those waters are given that they may contain all sorts of biologics, chemicals and sometimes salt water from the storm surge depending on where you live. It’s not the same as a big water heater breaking and covering the floor with an inch of clean, potable water.
Not only will you need to be diligent about washing your hands, but someone will need to disinfect walls, floors and all surfaces with an appropriate disinfecting and cleaning solution.
If you can't clean something, throw it out. That goes for soft goods like pillows, toys, mattresses, carpet and carpet padding.
Mold, mildew and water damage
Once you've extracted the water from you home, open doors and windows and use fans to help circulate air throughout the space. This helps everything dry out. The faster that happens, the less likely you are to experience mold, mildew and permanent damage.
Wood doesn't do well when wet for extended periods of time. If you have wood floors, laminate, vinyl or any other floors that include wood or wood pulp in its construction, you will most probably have to replace them.
You'll need to remove and throw out wet and damaged drywall and insulation which can also lead to mildew and mold.
From what we have observed, tile floors perform better in these extreme circumstances.
For example, a recent church mission project in Sumter, SC focused on an entire house that was flooded with 24" of river water and water from a failed sewage treatment plant. Everything in the house was removed including carpet and pad, hardwood, sheet vinyl, wood trim, drywall, and electrical. The only surface we didn't replace was the hall and master bath floors which were ceramic tile. This house was concrete slab on ground.
Additionally, the code enforcement officials in Sumter required a safety inspection of the cleaned and disinfected areas to ensure that there was no remaining mold or mildew in the structure prior to rebuilding.
Be certain to check the code requirements in your area before you or your hired contractor proceed with putting your house back together.
Evaluating flooded tile installations
Examine tile installations over wood
Any tile installation over wood that has been flooded will require close examination. Wood changes dimensions as a result of changes in moisture content. Until the wood is completely dried out, the extent of damage will be unclear. However, it will be suspect if it swells too much and starts rotting. Be sure to review all the wood framing in the home and determine on a case-by-case basis what passes inspection.
Robb suggests using a moisture meter to determine the moisture content of the wood subfloor after floodwaters have receded. Comparing these moisture readings to those of other wood surfaces in the house that were not exposed to flooding will help you determine if the surface is suitable for rebuilding. Once moisture levels in the floor are balanced with other parts of the house, you can assess the damage.
If tile has been properly installed, mold should not be an issue and the tile (and grout) can continue functioning effectively.
In any flood restoration where codes are followed and enforced, all food source items that remain (e.g., wood framing) must be treated with an antimicrobial solution and certified as mold-free by the local code enforcement officer before rebuilding can proceed.
Flooded tile installations over concrete with cementitious grout would possibly have issues with efflorescence, even on a well-installed system. However, the tile installation will hold up extremely well in a flooding situation and the efflorescence can be removed with an appropriate cleaning product.
>> See Understanding Efflorescence aka that Ugly White Powder on Your Tile
Watch new tile installations carefully
On new or "green" tile installations, ones that have been installed within 28 days of the flooding, it's best to contact the setting materials manufacturer and obtain an opinion on how to proceed.
Properly designed and installed tile installations over concrete, which include proper mortar coverage, bond coat thickness, perimeter, expansion and other soft joints in place, should perform well and survive extreme flooding.
Unfortunately on a poorly installed system, the potential is high for un-bonding of tiles along with mold and bacteria growth.
What if a membrane is involved?
Mark is concerned with how membranes perform in an extreme flood situation. More specifically,
- How long might it take for a saturated, on-ground system to drain from the bond coat down through the concrete and out into the ground?
- How long would drying out/drainage take if a crack, sound or uncoupling membrane is part of the system?
- How a flooded on-ground installation with a membrane will drain / dry out?
- How the membrane can be expected to perform after being flooded for several days?
- What about the effect of hydraulic pressure from below and above on membranes bonded to concrete?
- How well do flooded cavities on the bottom of uncoupling membranes drain or will they hold water?
In a flood, some membranes may delaminate within their own structure and cause a failure. The top of the membrane will stay bonded to the tile and the adhesive on the bottom (especially if the proper primer was used) will stay bonded to the concrete. In a flood, a failure can occur in the membrane between these layers.
An uncoupling membrane may help save a flooded tile installation on a concrete substrate. Flooded, saturated concrete will expand a greater amount than the tile layer. This membrane will do its job and uncouple the tile layer from the differing rates of expansion and should keep the installation intact.
>> See The Ultimate Guide to Underlayment for Tile
As to the membrane products (on concrete) be they A118.10 (Waterproofing), A118.12 (Crack Isolation), or uncoupling, those answers need to come from the manufacturers.
Water residing in the uncoupling membrane cavities shouldn't be a problem as this same process occurs during installation which allows the vapor to escape naturally. This would be further substantiated by the F128 method of an uncoupling membrane over young concrete. However, the ongoing contaminant issue needs to be addressed.
Be cautious when dealing with floods
Some folks enjoy doing the work themselves or - maybe out of necessity - have to complete flood restoration work themselves, but be cautious. The hidden biologic and chemical contaminants may not be readily noticed or understood. These types of determinations may be best left up to the flood cleanup experts.
These resources include information and additional links worth exploring relating to cleaning up after hurricane disasters:
>> The Environmental Protection Agency shares advice on how-to prepare for a hurricane and recover afterwards
>> From the Centers for Disease Control and Prevention, advice on cleaning up your home after storms
>> Here's advice from the US Department of Health and Human Services for safe cleanup
Not the final word about flooded tile installations
As we mentioned at the beginning of the article, we don't have all the answers. However, we are trying to gather the right questions to ask to help evaluate tile installations in these extreme weather situations.
We welcome your input.
Thanks for reading,
Note: We originally published this article on 09/20/2017, and have updated it.