Cleaning and Repairing Flooded Basements Entering
Before you enter a flooded basement:
1. Turn off the electricity, preferably at the meter.
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
Do not use an electric pump powered by your own
electrical system. Use a gas-powered pump, or one
connected to an outside line. Fire departments in some
communities may help with such services. More damage may
be done by pumping water from the basement too soon or
too quickly, than from letting the floodwater remain.
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 up.
To help prevent such structural damage, pump the
water from the basement in stages. Remove about a third
of the water each day. Watch walls for signs of failing.
If the outside water level rises again after the day's
pumping, start with a new water line. The soil may be
very slow to drain, but do not hurry the pumping.
Whatever is submerged in the flooded basement will not be
damaged further by delaying the pumping; serious
structural damage may be prevented.
Cleaning
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 one of these sanitizing solutions;
1. Chloride of lime (25% available chlorine). Dissolve a
12-ounce can in 2 gallons of water.
2. High test hypochlorite (65% available chlorine). Stir
5 ounces into 2 gallons of water.
Oil stains in basements caused by overturned or damaged
oil tanks may also be a problem following flooding.
Commercial products (such as Neutroda) will help
neutralize fuel oil 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, and let it set.
Repairing
Check supporting columns, beams, walls, and floors.
Structural damage to flooded basements usually includes
buckled walls, settled walls, or heaved floors. Buckled
walls are evidenced by horizontal cracking and walls
moving out of plumb. When this condition is minor, you
need not repair the wall immediately. However, any
noticeably buckled wall will eventually collapse from
normal ground pressures and season temperature changes.
When buckling has seriously weakened the wall, rebuild
the damaged parts immediately. Build pilasters into walls
over 15 feet long for reinforcement. Pilaster spacing
should be 12 to 15 feet.
Settled walls and footing 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. You may need
to construct a new floor.
1. Remove old, broken concrete.
2. Place 6 inches of gravel fill on the basement floor
surface.
3. Cover area with a polyethylene vapor barrier.
4. Lay a 4 inch concrete floor with mastic joints
between the floor and walls. The floor should be
reinforced with steel. Welded wire reinforcement placed
at mid-height in the slab is a minimum reinforcement.
If a floor is badly cracked, but has returned to its
original level, and if there is sufficient headroom,
place a new floor over the old one. Add a vapor barrier
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. Remove the mud as soon
as possible to avoid rotting joists or foundation wood.