Cleaning and repairing flooded basements

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Water usually comes into the basement from two sources:

Through windows, walls, and floors. If you don't have adequate drainage or grading around a home, the storm water will seep through those surfaces. Also, flooding may be contributed to malfunctioning sump pumps or drains (foundation or gutter).

Through sewer backups from the basement drain. If you live in an older area, a wet weather for a few days may carouse flooding. A sanitary sewer creates surcharges from inflow and infiltration (sometimes referred to as "I/I") when ground or rain water enters the sewer system through cracks in home sewer pipes. Among other causes are sewer blockages from grease, tree roots, debris, and deteriorated conditions in a city or home sewer line.

You need to call your city or town's Sewer Maintenance Operations Center. Though the problem may turn out to be in the private property line (responsibility of the owner), it is best to call the city first to check the public system.

If you live in a city setting, here are most common actions performed by the municipality to remedy the problem of aging sewers:

Inflow and infiltration sewer studies have been conducted in various older neighborhoods;

Capital Improvement Projects are normally identified as a result of the sewer studies. Solutions may include refurbishing older sewers by employing trenchless technology such as cured-in-place-pipe, sewer replacement, or adding additional/larger sewers to increase capacity.

Ongoing capacity studies to determine additional capacity needs. Additional capacity studies will be prioritized pending the acceptance of local authorities.

If your home was built prior to 1963, please check your downspouts to ensure they are not still connected to the sanitary sewer, which is now prohibited by city code. They should drain directly into the street or yard. Roof and foundation/footer drain connections add excess water to the sewer system.

Take a good look at the drainage system at your property. Ensure proper functioning of your sump pump and drainage system around the house. Clean your gutters and monitor them to ensure they are free of debris.

Run water from a hose through your home drains to check for blockages and ensure water is draining properly. Don't forget to check the grading around your home to make sure water is being directed away from the structures. If you notice "ponding" in the yeard, fill those and any other low spots.

To prevent sewer blockages, never dump grease, paint, or other thick liquids into your sinks or drains. Never flush items not suitable for sanitary sewer disposal, like paper towels, diaper wipes, contraceptives, and feminine products.

Make sure to verify with your insurance carrier if you have flood and sewer backup coverage, especially if you have a finished basement. This coverage may require a separate rider to your policy.

When you buy or rent a home, ask whether it is located in a flood plain or flood-prone area. Homes at lower elevations and those with depressed driveways are more likely to experience flooding problems.

If a sewer backup occurs, proper cleanup procedures must be followed for safety reasons. Never enter a flooded basement because the risk of electrocution is present. You must wait for the water to recede.

If you have a mature tree in the vicinity of your sewer line, consider removing the tree to avoid future problems with root invasion.

Before entering a flooded basement

  1. Turn off the electricity, preferably at the meter. Don't risk electrocution!
  2. Check outside cellar walls for possible cave-ins, evidence of structural damage or other hazards.
  3. Turn off gas or fuel service valves.
  4. Open doors and windows or use blowers to force fresh air into the basement.

Pumping a flooded basement

For safety reasons, do not use an electric pump powered by your own electrical system. Instead, use a gas-powered pump or one connected to an outside line. Fire departments in some communities may help with pumping services.

More damage may be done by pumping flooded basements too soon or too quickly. Water in the basement helps brace the walls against the extra pressure of water-logged soil outside. If water is pumped out too soon, walls may be pushed in or floors pushed up. To help prevent this kind of structural damage:

Remove about a third of the water each day. Watch for signs of structural failing.

If the outside water level rises again after the day's pumping, start at the new water line.

Don't rush the pumping; the soil may be very slow to drain. Whatever is submerged in the basement will not be damaged further by delaying the pumping.

Start out by picking up one or two small portable pumps from your local hardware or home improvement store. You'll rest easier once you have these sitting on a shelf in your garage (and not on the other side of your flooded basement).

Most portable pumps can be fitted with either a garden hose or a larger diameter drain hose. Spend the money on the larger drain hose, if you can ... a high capacity pump should be able to push more water through the bigger fitting. Be sure to buy enough drain hose to get the water far away from the foundation of your house (lest the water re-enter your basement).

When you're shopping for pumps, take note of the intake area. Some pumps will drain the water almost all the way to the floor. Other pumps may leave 3/8" deep puddles (or more) on the concrete.

Note: If your basement is seriously flooded, you may be able to enlist the help of your local fire department for serious pump out chores, and maybe even help mopping up the basement floor

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Cleaning a flooded basement

After water has been pumped from the basement, shovel out the mud and debris while it is still moist. Hose down walls to remove as much silt as possible before it dries. Floors and walls may need sanitizing, particularly if sewage has entered the basement. Scrub walls and floors with a disinfecting solution of 1 cup chlorine bleach per gallon of water.

Oil stains caused by overturned or damaged oil tanks also may be a problem following basement flooding. Commercial products, available from fuel-oil suppliers, will help neutralize fuel oil. The products come in powder form or an aerosol spray for hard-to-reach places. To remove oil stains and destroy odor: wipe up excess oil, shake or spray product on the spot according to manufacturer's directions, let it set, then sweep it up.

Once the portable pumps have done their job, big puddles are all that should remain. You can try pushing the standing water into the sump hole with a large floor squeegee or shop broom.

If you have a wet/dry shop vacuum, it's time to put it to work. Be sure to empty out the canister before you use a wet/dry shop vac to remove the standing water. Otherwise, you'll have to deal with a nasty gunky mess.

Having an extra pair of hands is a huge help. One person can use the floor squeegee or shop broom to consolidate the puddles, while the other person mans the vacuum.

Drying a flooded basement

After all of the standing water has been removed from the floor, you'll be left with a seriously damp basement. It's time to crank up the dehumidifier. For the optimum results, the dehumidifier will need to run 24/7 for days on end to dry out the dank basement air and saturated concrete.

Many dehumidifiers have an auto-shutoff switch that turns off the unit when the catch bucket is full. (This is a good thing ... otherwise the water would run all over the basement floor again.) While the auto-shutoff may be useful under normal conditions, it's pesky when you're running the dehumidifier non-stop. You'll probably want to modify the catch bucket to avoid running up and down the basement stairs a few times a day.

Check to see if the unit has a drain fitting on the bucket to attach a garden hose. If it does (and it should) you'll be able to run the dehumidifier continuously until the basement is dry. Route the drain hose into the sump pump hole and you should be good to go.

Clearing the water out of a submerged basement isn't just a pain in the neck. It can be dangerous, as well. Electricity and water are never a good mix. Be sure to take the appropriate cautions to avoid any shocking situations.

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Inspection and repair

Before beginning repairs, make a thorough inspection of supporting columns, beams, walls and floors. Unless you have structural expertise, hire a contractor to make a professional survey. (Consider joining with neighbors for a group-rate inspection.) Repairs may extend to the following:

Settled walls and footings are indicated by vertical cracks either in small areas or throughout the structure. Repairs are difficult without special equipment. Contact a reliable contractor for this work.

Heaved floors are those that have not returned to their original level or have cracked badly. The floor may have to be removed and a new floor constructed. If a floor is badly cracked, but has returned to its original level, a new floor may be placed over the old one. A vapor barrier should be added between the two floors. The new floor should be at least 2 inches thick.

In houses without basements, the area below the floor may be completely filled with mud. Shovel out the mud as soon as possible to avoid rotting joists or foundation wood.

Reducing odors

A chlorine bleach solution may be used to remove odors from basements that have been flooded.

After checking the structural safety of the basement and removing water and mud, use a coarse brush or long-handled broom to scrub down the floors, walls and ceiling.

First, spray surfaces with luke-warm water to remove flood residue. Start with the floor, then move to the bottom of the walls and work your way up. This will lessen the chances of leaving muddy streaks on any basement surfaces.

Next, use hot water with a heavy-duty cleaner to scrub all surfaces, again, starting at the bottom and working up to the top. Follow up with a rinse using a brush moistened with a solution of two tablespoons chlorine bleach per gallon of water. Repeat the scrubbing and rinsing until the odor is gone.

You'll want to dry out the basement, but if the outdoor air is humid, don't open the windows to do it. It's better to run central air conditioning or a dehumidifier. These methods will remove moisture from the basement air. Running a fan also will help dry things out.

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These items will be really nice to keep around after you've cleaned and/or repaired your flooded basement!

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Black mold problems

Most homeowners are unaware of the extreme health problems that can be caused by the growth of mold in a basement. Additionally, the presence of mold can present difficulties when trying to sell your home, and in extreme cases, mold can cause structural damage.

Basements that would never develop mold under normal circumstances can develop a mold problem after basement flooding. The dampness alone caused by a flood provides plenty of moisture for mold to grow well in your basement, and the filthy backup of raw sewage provides an even richer medium upon which various mold may thrive.

If you have gone through the trouble and expense of mold remediation after a sewer backup that caused basement mold in your home, you would be foolish not to invest in the installation of a backwater valve to prevent the flooding problem from occurring again.

Mold on basement walls can easily grow and spread into the floors and walls above. Additionally, air born mold spores from the basement mold can travel through the air to contaminate other areas of your home. The heating and cooling system, generally located in the basement (where the mold is present) provides and easy pathway to the entire house.

Speaking to the health issues, allergies to mold infestation can cause open sores, skin rashes, itchy skin and eye irritation.

You can buy do-it-yourself mold test kits hire a Certified Mold Inspector. When working with mold yourself, you should use a breathing air respirator (sold at you local home center or hardware store) to avoid inhaling mold spores that you stir up with your efforts.

Another little known fact by the average homeowner is that bleach is too weak to be an effective mold killer and is NOT EPA-registered as a mold fungicide. To achieve the maximum mold killing power, you must use use two wet sprayings of EPA-registered fungicide and Tim-bor antimicrobial protective coating.

Again, if a backed up municipal sewer system is the water source that enables mold to grow in your basement, YOU CAN NOT CONTINUE TO HAVE BASEMENT FLOODS IF YOU WANT TO RID YOUR HOME OF MOLD AND KEEP IT THAT WAY. Stopping the water/sewage problem with the installation of a backwater backflow prevention valve must be your number one mold remediation step!

Steps to remedy a mold problem.

If you believe you have a mold problem, there are several steps you must take.
  1. The air in the basement must be mold tested.
  2. The air of each room above the basement must be mold tested.
  3. The attic must be mold tested.
  4. The garage must be mold tested.
  5. The outward air flow from each heating/cooling duct register must be mold tested for the possible presence of elevated levels of airborne mold spores.
  6. All of the above levels are compared to a baseline outdoor mold control test which you should also conduct.

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Hurricane related flooding (Part 1)

There are a series of factors that may be responsible for basements flooding. It can indeed be your masonry walls, but it can also be undersized or clogged roof gutters and downspouts. The soil around the house could have flat or negative slope so that water pools against the foundation. To add insult to injury, the original builder may have never truly waterproofed the foundation.

The hurricane or tropical storm winds that pounds homes are truly powerful. Rain that pelts against houses with even a mild breeze during a rainstorm can create leaks in walls that seem to be impervious to water. Imagine thousands or even tens of thousands of drops of water combined with the actual wind pressure of a tropical storm or hurricane driving the water deeper and deeper into the walls.

The most common entry point of water into a masonry structure is through the vertical mortar joints in brick, concrete block, and stone. Even though you can't see cracks where this mortar touches up against the masonry units, lots of water does penetrate here. If the builder did not create a system for this water to be collected and redirected to the exterior, leaks can occur.

Once the walls dry out, they can be sealed very effectively with a two-step process of water-based products. The first step is the application of a clear penetrating silane - siloxane water repellent that coats the entire masonry wall. Two coats must be applied and they must be applied within 30 minutes of each other. If you wait too long between coats, the first coat of the water repellent actually starts to work and stops the second coat from entering the masonry units and the mortar.

Immediately after the water repellent is applied, a masonry joint sealer may be applied, a milky product that has the consistency of canned gravy before it is heated. Once applied in a thin coat over the mortar joints and a portion of the brick, it dries clear. This product, when applied correctly, can bridge cracks up to 1/8th inch.

Hurricane related flooding (Part 2)

The water that falls onto the roof and the land around the house must be captured and diverted to the lowest spot on the lot.

For example, if 4.5 inches of rain fell at a house during the storm, and the roof area and combined yard area are one-half acre, the rainfall dropping onto the property would be about 61,096 gallons of water! If a lot receives water from an uphill neighbor, then even more water was charging towards your basement. Don't believe it? Check for yourself!

It is imperative to capture all roof water with gutters and downspouts. The water from the roof should enter an underground piping system that directs this water to the lowest part of your property. Be sure local codes allow such apprioach. Some municipalities require storm water to be piped to a special storm water system that retains it and slowly releases it over time to the natural streams and rivers in the area.

An underground yeard gutter system should also be installed. It captures any subsurface and surface water passing through and on top of the soil. A 6-inch wide, 18 to 24 inches deep trench can be dug out. A perforated drain tile should be installed inside the trench, then filled to the top with washed rounded gravel.

Once the pipe passes the house and is headed towards the lowest part of the lot, the pipe must be leveled in the trench. Since most building lots have some slope to them, the pipe will eventually extend to daylight and be visible. Water will gush from this pipe during and immediately after a heavy sustained rainfall.

The next time you are a passenger in a car being driven through a moderate rain storm, open the window and let your hand get hit with some of the rain drops. You will be shocked how hard they hit your hand even while driving 30 miles per hour. The force at 70 miles per hour is almost painful.

This type of energy can easily defeat walls that have not been perfectly waterproofed. The new masonry sealing systems are effective, water-based and can last for up to ten years between applications. An even better characteristic is that they are very do-it-yourself friendly.

by

vincechan

If your basement is flooded, don't be in a hurry to pump the water out! Here's a comprehensive guide to properly cleaning and repairing your flooded ba... more »

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