Are You Looking at a Flood Damaged Fireplace? How to Investigate!

**Our honesty policy: This post may contain affiliate links and I may be compensated if you make a purchase at no extra cost to you. Some are, some aren't--I do some comparison shopping. The important thing is you will know exactly what we are talking about. Drop a note/comment if you have any questions on the products as these are materials and tools we use on our own projects.

In the previous post we touched on the sanitary problems behind leaving a brick fireplace* in place after a flood.

“…mortar and brick are porous. Brick may be salvageable if it is a higher quality like fire brick. However, if it is not properly dried and cleaned the moisture from the unsanitary flood water is still present (as are all contaminants in flood water). Even if the home is properly remediated, the fireplace may not be salvageable.”

So at this point we know a flood soaked fireplace is sketchy.

Sure, the house may be remediated. But a brick cleaned on the outside does not equal clean on the inside, where you can’t reach the flood materials soaked into the mortar. Nor can one reach the core inside the fireplace. This is starting to sound like tile…

When you are looking at a newly remodeled home in an area with recent flooding, the new question is, “How do we know if a brick fireplace is dry?”

There are actually a few different methods to determine if a fireplace is dry. We will go over three of the methods going in an order that is most effective to least deterministic.

In our testing with the different methods below we know how high the water flooded in two ACTUAL sample flooded homes. One home is properly remediated. The second is not, but all materials such as drywall and tile flooring were properly torn out below the flood line in short order once flood waters receded.

We will discuss the results of taking measurements above and below the flood water line.

Moisture meter

A pin moisture meter uses a penetrating probe detecting the amount of moisture in the mortar**. The moisture meter gives you a real ratio number with the percentage of water content held in the tested area.

Although the moisture meter is a “penetrating” method, no mortar is damaged in the process of taking the measurement using our particular all-in-one moisture meter: Protimeter MMS2. Instead, the pins on the head of the meter are held directly and firmly on the surface.

“The instrument can now be used to take actual %MC (moisture content) readings in wood and %WME [(wood moisture equivalent)] readings in non-conductive solid materials other than wood by placing the moisture probe pins in firm contact with the surface” according to the MMS2 owner’s manual. The meter also displays the translation of the percentage on the bottom right, indicating if the reading is dry, at risk, or wet.

Picture of a the Protimeter MM2 testing above the flood water line of a post-flood remediated brick fireplace: WME of 8.6% (DRY).

Picture of a the Protimeter MM2 testing below the flood water line near the floor of a post-flood remediated brick fireplace: WME of 19.8% (RISK).

Picture of a the Protimeter MM2 testing above the flood water line of a yet-to-be-cleaned post-flood brick fireplace: WME of 8.3% (DRY).

Picture of a the Protimeter MM2 testing below the flood water line of a yet-to-be-cleaned post-flood brick fireplace: WME of 20.1% (WET).

We also took pictures of the base plates to show that seven months post flood the framing–even the base plates which are the most likely pieces of wood to retain water due to gravity pulling water down–are dry even in an unremediated home. However, the unremediated home could blossom into a mold infested home if even clean water is reintroduced to the untreated surfaces.

Picture of a the Protimeter MM2 testing the moisture held in the base plate of a remediated post-flood home: WME of 8.0% (DRY).

Picture of a the Protimeter MM2 testing the moisture held in the base plate of a yet-to-be-cleaned post-flood home: WME of 10.1% (DRY).

Plastic wrap and tape

There is always the old school route where you wrap the questionable tile or brick in plastic. This method utilizes a sheet of plastic over the area taped in place on all sides. The end goal is to trap all moisture so you can confirm if there is water still present.

No, it’s not exactly a fireplace, but you get the idea…

The downside with this method is you need access to the house for some period of time. A simple walk through tour most of us take when viewing a house is certainly not long enough. A few days is more like it.

Adding some heat speeds up the process. But, again, if the house is not yours you are not likely to control the thermostat either.

Of course, if the fireplace was painted during the remodel this check is not effective. However, it might make you question what is seeping out the backside of the fireplace brick. What is growing behind the wall because half the surface allowing the water to escape is blocked?

Thermal imagery camera

The idea behind a thermal camera is to visualize the surface temperature of almost anything within the camera’s focus distance.

My theory was our FLIR C2 thermal camera would detect and display the water line on the fireplace. I was very surprised to find the camera failed to show much difference despite the moisture meter readings above.

Thermal camera image of the same properly remediated flood damaged fireplace as shown in the moisture meter pictures above.

The difference in temperature between the water soaked mortar and brick and the dry mortar and brick is almost negligible if the water is not very recent (and these pictures are taken seven months after Hurricane Harvey). Instead, the fireplace is so huge it acts as a thermal mass structure, slowing down the more easily changed ambient air temperature in the room. The flood damaged fireplaces have very much gone back to a unified temperature.

Example of a FLIR image on a recently used outdoor water spigot with water over spray on the brick exterior wall.

The actual image of the water spigot for comparison purposes.

For the most part, a home will not be thrown together in the two weeks following a flood. Some will. However, it is probably doubtful you are actively looking without knowing a hurricane went through the area based on every major news network.

Even if you did not know you might put two and two together by detecting the clues on every single front yard of your potential new neighbors…

Just sayin’.

As much as I enjoy using our FLIR C2 thermal camera for so many other puzzling detective purposes, unfortunately, it is not your best tool in your tool chest at detecting if a fireplace needs to go after a lot of time has passed after a flood.

 How to interpret our findings on a flood damaged fireplace

Based on our moisture meter readings, even if a home is remediated it is not a good idea to keep a fireplace after a flood. Clean or unclean the numbers are basically the same when it all qualifies as wet!

A flood damaged fireplace still oozes contaminated flood water down and out over time. The moisture and contaminate will not show up as a clear damp spot, but as increased humidity, odd smells (like a basement sometimes), and possible mold growth and/ or efflorescence.

Also keep in mind if the home is remediated–specifically the drying process–you are testing the driest part of the brick. The inside part has a higher percentage of moisture. So it only gets worse behind the brick.

WOW, the price tag on that meter and camera!

As mentioned before, “while the price tag [of these meters and cameras] may surprise you, it is certainly less than the price tag of demoing out the old fireplace and replacing or permanently removing it.” Think about the amount of work it is to remove the brick and framing, patch the roof and ceiling, and fix the exposed foundation to match (or replace) the rest of the flooring in the room.

What if you want to keep a fireplace?

You can avoid the issue of patching the roof, ceiling, and flooring if you replace the old fireplace with the exact size replacement. Best of all, you can pick your own style! Stacked stone, a different color brick or other finishing tiles and stone are all on the table at this point. A new, beautifully finished fireplace is a enjoyment (and selling) feature.

Alternatively, you could go back with a more effective heat producing stove. While the previous problems all need fixing, you are still left with a fireplace. A very useful one on a cold winter night, at that!

Once you remove a fireplace, your insurance payment goes down because you are essentially making a fire less likely in your home. You also reduce your heating and cooling costs because you no longer have a chimney and imperfectly sealed structure protruding out of your home. However, you may not be allowed to put one back at a later time without working with your city’s building/ permitting department.

Keep yourself in the know

If you are not sure if the home flooded use your testing device of choice and use it as close to the floor as possible–preferably before you buy the home.

Only you know if this is a project you want to tackle after purchasing the home.

*This article is specifically targeting wood burning/ gas fed brick fireplaces. Of course, there are many kinds of fireplaces out there. They all have different needs for remediation.

For instance, if you have an insert with a metal box consider the galvanized steel, once submerged and then exposed to air, will deteriorate. If/when it gets to the point of rusting out even with pin holes there is now access to air, increasing the likelihood of a fire. Replace it!

The same goes for a gas fireplace or electric fireplace. For your safety get them checked out by a professional and replace items like gas logs and electrical wiring.

These fireplaces are not intended to ever be submerged. A flood certainly voids the warranty.

**We are pinpointing the mortar as it will soak up more water than the brick.