List of News Articles for HOA's

Article #01:

HOW TO PREVENT OR REDUCE
WATER POOLING AND LOT FLOODING

In the last few years our property maintenance firm has had an increasing number of calls to eliminate water pooling and flooding problems, especially on low-lying property lots.  One of the major culprits of lot flooding is the rainwater from the roof.  Try these steps to remove this water from the lot.

1)  Avoid galvanized steel or plastic gutters ...

When you replace the rain gutter system have only aluminum or copper gutters installed.  These rust proof gutters can be pitched to divert the water to where you want the water to go.  Galvanized steel gutters should not be installed in a manner such that water can collect inside of them.

2)  Pitch the gutters towards the sewers ...

Pitch the gutters toward the part of the gutter system that is nearest to the street, drain, downhill side of the lot, etc.   Even galvanized steel gutters can be pitched properly by an experienced installer.   Do not let an installer hang the gutter system level !

3)  Use fewer, larger downspouts ...

Don’t install six or eight small downspouts from the gutters.  Use just two or three large 2x3 inch or 3x4 inch commercial downspouts and install them in the part of the gutter system that is nearest to the street, drain, downhill side of the lot, etc.  Two 3x4 inch downspouts have 24 square inches of volumetric area while it requires eleven 2 inch round (Actual diameter is 1.65 inches inside) to carry the same water.  The eleven small downspouts will block constantly because of their small apertures while the two commercial size downspouts will even pass tennis balls right through.  The cost of the two commercial size downspouts is about equal to the cost of four or five small downspouts.

4)  Stay away from sharp corners ...

Do not use rectangular downspouts which have sharp-angled elbows that will catch debris easily.  Use fluted, rounded-corner rectangular downspouts that have rounded elbows, which pass most debris right through them.  Also, do not use any elbows with greater than 75 degrees of bend.

5)  Beware of small roof and gutter outlets ...

Roof drain outlets and gutter outlets are the funnel-like short pipes that let the water flow from the roof or out of the gutters.  Make sure that these are the same size and shape of the downspouts.  A small 1.5 inch round gutter drop leading into a 2x3 inch downspout only lets enough water through to fill less than one-third of the downspout capacity.  This is a common installation error occurring in over fifty percent of the gutters installed in new structures.  The gutters overflow needlessly.   Naturally a 3x4 inch downspout requires a 3x4 inch outlet.

Rainwater in the gutters will run efficiently around three right angle corner bends at most.  If there are more than three bends in some sections that you don’t want to have a downspout, pitch the gutters to run from this location toward both sides.  In this manner water can move through six corner bends by simply having the water run through three bends in each direction.

Don’t install any downspouts on the uphill side of the structure or in any area where water accumulates or drains under the foundation.  Keep these areas free of downspouts.  Pitch the gutters away from here.

Direct all downspouts to either pour onto pavement that flows away from the structure, empty into a drain pipe, standpipe or drainage system.  If not, at least make sure that downspouts have extensions that extend several feet from the structure.

Landscape drainage systems ...

Use the force of gravity by constructing a passive drainage system, operated by a natural siphon effect, to remove the rainwater.  Dig a shallow trench, just a few inches deep, or deeper to pass under sidewalks, etc.  Install an inexpensive polystyrene or similar plastic three inch, four inch or, rarely, a six inch, pipe through this trench.

Using this passive drainage system, water will run under sidewalks and obstructions and the force of gravity will actually force the water to rise back up and bubble out of the end of the drainage pipe.   Remember, the standpipe at the downspout end has to be higher and the pipe can have no leaks.  This passive system is not a sewer line and does not need a plumbing permit.  This system is called a "landscape drainage system".

If the passive drain runs slowly after a few years, put a short jet nozzle on the hose and push it through the pipe.   It will unblock in a few minutes.

Clean the gutters every year and check the downspouts for blockages.  We clean the rain gutters for some clients twice a year, once in the spring to remove winter debris and prolong gutter life, and once in the autumn to remove the first autumn leaves and be ready for the rainy season.

Don’t install a "French drain" near the property.  They easily overload, usually block up with sediment and always attract termites.  Use the passive drainage system described here instead.

One last tip: Build a little dirt embankment about three inches high against the building when feasible. pitching gently away from the structure.  This stops small constant pooling that can attract subterranean termites, and also diverts water that runs down the walls during a storm.

If you are an existing client of ours or if we are already on your Vendor List, and you have questions, you can call us at 650/424-7809 and we’ll try to give you the answers, free of charge.  We perform all of the work described herein and will give you a free estimate if you request one.

 

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Last updated on 28th May 2004.
Webmaster: David Goh