If you have recently encountered a flooding situation and are attempting to dry out your dwelling on your own this information may be very helpful to you.
This information only pertains to floods on ground floors with concrete underneath. Any flood that has wood or other structural materials with cellulose fiber that would be a food source for microbial growth underneath a layer of carpet should be addressed by a flood restoration professional. Failure to properly address wet structural materials will become much more damaging to the dwelling than the replacement cost of carpeting. For this reason and the consideration of the extreme expense of mold remediation the dwelling is always of first concern. Any flood that is not addressed within 12 hours also should not be attempted without consultation of a flood restoration professional as secondary damage needs to be assessed for a proper drying plan. For more information regarding mold related issues visit www.epa.gov/mold/moldresources.html
For a small flood you will need these items.
1.) An ample number of bath towels.
2.) A dehumidifier.
3.) A box fan.
4.) Lysol disinfectant spray
Many times when you have a flood the damage that is commonly known as secondary damage can be very costly. This damage can be eliminated by a fast dry up and application of an antimicrobial disinfectant if done in a timely manner. First let’s get familiar with what is going on in your dwelling when you have a flood.
We need to first determine what type of flood you have. There are 3 types
1.) Sanitary Water Flood. (Caused by a sanitary water supply line within the dwelling.)
2.) Gray Water Flood. (Caused from excessive ground water, the major contaminants here
are silt and nitrates from fertilized soil.)
3.) Black Water Flood. (Caused from sewage or septic back up. Many pathogens and
bacteria’s may be present here and present possible health risks that should be addressed
With types 1 & 2 Sanitary and Gray Water floods in most cases textiles and structural material can be restored depending on the severity of the flood. With type 3 Black Water Floods all textiles and wall board affected should be discarded and studding treated with a sterilizer. This type of flood should only be performed by a professional experienced with disposal of contaminated waste and proper remediation of contaminated structural material.
Lets concentrate on flood types 1 & 2 that you can handle provided it is not too severe. If you have experienced a flood in your basement and it is not too large of an area you may possibly be able to handle this yourself. When you first look at your flood you are probably thinking the only damage you have is the wet carpet you are standing on. The reality is that if you don’t act fast you will also have a lot of hidden problems that will start to show up in about 72 hours. If your wet carpet also has padding underneath, this holds a lot of water. Most quality carpet installers will usually opt to install in a basement – carpet and padding that are of the mold and mildew resistant type as well as padding with a permeable membrane, you can contact your carpet retailer to find out if this was done. If this is the case your textiles are not a food source for microbial growth unless they are literally contaminated with food spills or other contamination such as pet accidents etc. In this case you may want to consider treating this flood as a Black Water Flood and discard the textiles affected. Also if your carpet retailer tells you your padding doesn’t have a permeable membrane, you will have to have this padding removed to properly dry out dwelling. If this is not the case the next thing we are concerned with is the dwelling (Structural Material).
When you have a wet carpet tucked up against a finished wall you will experience absorption of the water from the textiles into the walls and in many cases it can climb a sheetrock wall very quickly. This absorption is known as capillary action due to the permeance of the structural material. While the synthetic textiles aren’t a food source for microbial growth, structural material that is full of cellulose fiber is. This is the area where you will incur secondary damage after the original flood if the carpets that are commonly known as the reservoir of your flood are not dried out in a timely manner.
So now let’s get to work drying out your carpets so you don’t get secondary damage in the form of mold growing in your walls. If this was a small flood in an area of 3 or 4 square feet you can probably use towels to absorb as much moistures as possible out of the carpet and padding, If the carpet was installed direct contact, glued down directly to concrete without padding this will work fast, if not you will go through many towels while actually continually stepping on the towels to force the water out of the padding. When you get to a point where you have very little water transferring into the towels you are ready to go on to the next step.
The next step is to apply a disinfectant to the surface of the carpets and even more importantly is to flood the base of any walls where wet carpet touches the wall areas. The disinfectant that you can use is Lysol Disinfectant Antibacterial Spray (available in supermarkets) this is the aerosol type that most people have in their bathrooms. This type of disinfectant is alcohol based and will use the moisture in the walls as a carrier and travel some of the way that the water did. Remember the Exxon Valdez, oil floats on top of water, well same premise here the solvent will climb the moisture so flood the base of those walls good.
The next step is to set up a closed drying cycle. To do this you will need to close off all exterior windows and close off any areas not affected by flood to reduce the total cubic feet of area you are working on. You will want to bring the temperature to approximately 72 degrees Fahrenheit, this is the optimum temperature for drying. A common misconception when trying to dry a dwelling is that high heat is optimum for drying. While high heat will dry faster, high air temperature will also raise the mold spore count through the roof creating a perfect breeding ground for fungi in the presence of high humidity which is common in flooding conditions. The only exception to this would be if you have infra-red radiant heat which only heats objects in the room not the air. With infra-red radiant heat you would be able to heat walls above air temperature creating higher vapor pressure in wet structural material than that of the air, which would decrease structural drying time. You probably don’t have radiant heat and this is very complex drying theory, so just set your heat on 72 degrees Fahrenheit for the best outcome.
Next you will need a dehumidifier and fan to speed dry the final moisture. Your goal here is to attempt to bring the relative humidity down to 20% to 25% RH (which is about as low as can be expected of a refrigerant type dehumidifier), and circulate air across the surface of all wet textiles. The reason you are attempting to minimize the cubic feet of the flooded area is the dehumidifier will become more efficient in a small area as opposed to a huge area. This is important due to the fact that if the relative humidity is not lowered to below normal conditions both structural material and textiles will not shed moisture and the structural material will continue to absorb moisture and microbial growth will almost be certain to form in walls. As important as the dehumidifier is, the fan is equally important in the drying process. As stated earlier the carpets are commonly known as the reservoir of your flood and if not properly dried they will continue to feed secondary damage. When trying to dry wet textiles that hold the majority of the moisture, a natural atmospheric phenomenon will occur similar to the way clouds form. This is a boundary layer of moisture just above the surface of the carpet. It is important that you understand some of these critical closed drying cycle issues if you are going to be successful in drying out your flood. When water evaporates off a surface it creates a cooling process, approximately a 30 degree temperature drop. If you have your room temperature set at 72 degrees (which is optimum for drying with a refrigerant type dehumidifier) and have a dehumidifier set up, as evaporation starts to take place the temperature at the surface of the carpet will drop down to approximately 42 degrees. As we know warm air rises and cool air drops, we also know that warm air holds more moisture before it becomes saturated. With this in mind if you didn’t have a fan set up, very shortly after starting the dehumidifier evaporation would start to take place at the surface of the carpet creating a temperature drop of 30 degrees and now the cold air at the surface of the carpet would become saturated as cool air can’t hold much moisture before its point of saturation. At this point when you have a 1 to 2 inch layer of cold air that is at 100% saturation just above the wet carpet it is creating a boundary layer of moisture that will stop any further evaporation to take place, hence bringing your drying cycle to a complete standstill. Without positioning a fan correctly to force the cold air that wants to hang down by the carpet up higher in the room where the dehumidifier can collect that moisture and start to work at peak efficiency you would be left with either a poor drying cycle or no drying at all. It is also critical not to position a dehumidifier directly into the path of a fan. A refrigerant dehumidifier works by the premise of moving warm air past a cold coil and creating condensation. If a fan that moves too much air (as a commercial blower with approximately 3000CFM) is directed at a coil that is capable of condensation with only about 115 CFM the end result would be a dry coil that does not create any condensation.
Once you have taken these steps you will need to leave the equipment running for at least 4 days but a week or longer is preferable as the carpet will probably be dry in 3 to 4 days the walls always take longer. If after 5 or 6 days the room starts to become exceptionally hot even if you have completely turned the heat off, do not worry this is a very good sign. What is happening is that the moisture in every cubic foot of air that passes the dehumidifier condenses from a gas state to a liquid state, which takes energy or BTUs (British Thermal Units) and excessive heat is the end product left behind. When the excessive moisture in the carpet was creating a cooling the temperatures were tending to equalize each other out. Now that the excessive moisture in carpet is gone and we are still removing moisture from the air we are gaining a net warmth overall. The reason this is a good sign is that it is telling you excessive moisture is gone and now with low humidity and high temperature you no longer have to worry about a high mold spore count. Also, you now have more molecular activity to help dry the walls, wet wants to go to dry, warm structural material creates higher vapor pressure of remaining moisture so any remaining moisture in the walls as long as it hasn’t climbed too high should migrate to the dry room cavity. Your carpets should have been long dry at this point and if you started your dry out process within the first 12 hours as stated at the top of this page, you more than likely should not have more moisture in the walls than a week or 2 of this procedure would correct. One tell tale sign if the walls have not dried out properly would be odor. If you have an odor continue to run the dehumidifier as controlling the moisture will control microbial growth.
When we come in to your home and dry out the dwelling in a 1 or 2 type flood, one of the things we do is an inspection to find all the parameters of moisture. This inspection entails first probing all affected textiles to find parameters of moisture, checking textiles to see if they are mold and mildew resistant, and checking to see if padding has a permeable membrane so that we can dry carpet and padding in place. Next we use non probing conductive type moisture meters to find hidden moisture in walls and wall cavities. Normal moisture content of structural material is 10.2% and if our meters determine that the moisture content exceeds 18% (which is the point at which microbial activity takes place in cellulose fiber materials) it is than important to create a proper drying plan to reduce or eliminate secondary damage. The final part of our drying plan consists of the use of a hygrometer to evaluate room temperature and relative humidity and apply this to the overall cubic footage of the area affected so as to compute the proper amount of equipment needed to properly dry the dwelling after mechanical extraction and antimicrobial applications have been performed. In cases of severe flooding and multiple level flooding more invasive measures have to be taken to dry out wall, and ceiling cavities, wood flooring, cabinets and other areas of hidden moisture. Most times in these cases textiles are discarded due to their hindrance in the more important objective of restorative drying of the dwelling.
For more information regarding flooding contact us directly at the branch nearest you. See “Branch Territories“