Got Mold? Part 3 – a flood doesn’t have to be the end of the world


By now, you’re probably terrified of water, and well you should be – it is a silent destroyer of homes. On the other hand, I don’t want anybody freaking out because they spilled a bucket or even a glass of water on the floor!

Mold doesn’t grow instantly. It needs time, water, and sometimes warmth. I’ve seen plenty of cases where people have had a serious flood in their homes – perhaps a toilet or sink flooded a bathroom, but these resulted in no mold. Why? Because the water was cleaned up quickly and everything was allowed to dry out.

The danger is when you let water or condensation get trapped somewhere. For example, I see this a lot – house-plants causing rotten wood, like shown above. There was a huge house plant sitting in a plastic pot. The pot didn’t leak, but periodically, somebody might spill a little water which would go under the pot and get trapped. Over time, it totally ruined the oak floor.

Trapped water is bad. Water left to evaporate is usually harmless.

Most of the mold and water damage I’ve seen occurs over a long period. Weeks, months or even years of neglect. So it usually isn’t a surprise when you find problems. However, like the proverbial slowly boiling frog, we often ignore a “little” condensation or a puddle of water. But, these are exactly the things that cause you to wake up one day and find that your window sash has rotted out.

A little moisture over a long period can cause serious damage.

Let’s look at a few scenarios and classify them as bad or not-so-bad.

Scenario 1:

Your toilet or sink overflows, but you catch it quickly. Maybe a couple buckets worth of water floods your bathroom.

First off, any time you have a water spill, the first thing to do is to clean up all the water (duh)! If you have a wet-use shop-vac, you can put it great use. Shop vacs do a wonderful job of cleaning up spills because they’ll suck the water off the floor and out of nooks and crannies. If you don’t, then use a sponge mop and soak up all the water.

When you’re done with the bulk of the cleanup, use an old towel to dry everything as well as you can.

Often, this simple cleanup will be enough if you catch the leak before it has a chance to really soak in. So beyond this, just run the bath fan for a few hours to flush out the moisture in the air or run a big floor fan in the doorway. 

All told, this type of “water event” can be pretty harmless. 

Scenario 1a:

You flood the bathroom with enough water that it drips out the ceiling or light fixtures in the floor below. 

This could mean trouble. In most homes, you have the finish flooring, with a wood sub-floor underneath. This sits on the floor joists. Underneath, the ceiling material, usually sheet-rock, is nailed or screwed to the underside of the joists. If the water flooded down to the floor below, that means that a substantial amount is likely in this space around the floor joists which you can’t get to in order to dry it out.

As in scenario 1, you want to immediately clean up the water above. Forget the floor below (yet) – stop the water above from coming down! If you clean up the water and get the bathroom drying out, that will help the water evaporate and allow all the building materials to dry out. Remember – water “wants” to move from wet to dry areas.

However, your work isn’t done yet. There’s a good chance that your sheet-rock will pull away from the nails/screws that hold it up. When it gets wet, sheet-rock will turn to mush. Don’t touch it or you may destroy it. You also run the risk of having the ceiling collapse on your head.

The best thing to do is clean up all the visible water from the bathroom and the floor below and then put dehumidifiers in both rooms. Let them run for a couple of days. You literally want to suck the moisture out of the building materials as fast as possible.

If you’re a professional and have good toys, you can use a moisture meter. I have a few of these. They let me scan behind walls and ceilings without having to take everything apart. There are two types – the pin type, which is generally more accurate but requires that you stick the probes into the material, and non-destructive, which works on the electrical properties of the material which change with water content.

The problem is, if you don’t have one of these meters, you really don’t know how much water remains in the ceiling cavity. If that water isn’t totally dried out quickly, you’ll probably have mold growing in there. You will be very unlikely to have wood rot however because the water will get soaked up and evaporate over time so the conditions for continued mold and related problems decreases over time.

The question is, if you do get a little mold in there, is that a problem?

Before I answer, if you have any doubts whatsoever about you or your own family’s sensitivities to mold, contact a professional. Without actually examining your home, there is no definitive information that anybody can give you. In other words, if you choose not to have a professional evaluate your problem and your house collapses or you die of mold allergies – don’t blame me!

There is a school of thought that as long as you get rid of the water let the mold grow in the first place, you don’t want to mess with it, especially if it’s safely trapped in the walls or ceiling.

What would I do? When I’ve had situations like this in my own home, usually after I’ve dried things out, I will cut a hole in the ceiling – maybe 16” square. Large enough to poke my head into and check things out. Sheet-rock is easy to patch, and you’re better safe than sorry. Though now that I’ve got those excellent moisture meters, if they indicate that it’s dry in there, I don’t worry about it.

Scenario 2: 

You’ve had a flood that you didn’t discover for a couple weeks.

This is bad news, really bad. I’ve seen homes totaled by this. Seriously.

This typically occurs when a pipe bursts in a vacation home. Or a rat chews through the water lines of your dishwasher or washing machine. The water pours out, gallons every minute, for the entire time. It’s horrible. Thousands of gallons flooding into every corner of the house, soaking into the carpets, up the walls, into every cavity.

In a situation like this, the only solution is to call in a water damage specialist. Hopefully your insurance will cover this, because it will cost thousands of dollars and take potentially weeks to dry out your home and determine if it’s habitable.

Here’s what they’ll do.

First, as in any of these situations, they’ll turn off the water to ensure that no more water enters. Next they’ll remove the “bulk water” so that it can’t cause further damage. This is the easy stuff.

Next, they’ll probably want to remove all the water soaked materials. This might include sofas, carpets, beds, anything that is wet and holding moisture. If they leave these giant wet sponges in the house, it will be extremely difficult to dry out the house.

After that, they’ll use industrial strength dehumidifiers and fans to dry out the air. The fans help to evaporate the water and the dehumidifiers suck the humidity out of the air. 

If you’re lucky, they’ll make measurements using meters like I mentioned above, and they’ll determine that the interstitial spaces (i.e. inside the walls and floors) are dry. However, with this type of flood, it is extremely likely that the insides of the walls and floors will be saturated with water. This can be extremely difficult/impossible to dry out without opening up the walls.

As you can see, this is really serious. If you encounter this type of scenario, don’t mess with it!

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