Roof Leaks Spell Disaster

  Let me first tell you a personal story.  For eight years we had a home overlooking a lake.  The day we moved out and my workers removed all the clothes out of my closet I discovered the walls covered in mold in the far corner.  Apparently, during a particularly bad storm with very high wind gusts, shingles had blown off the corner of the house that was two stories high and I never knew or suspected a thing.  Rain water had intruded running down the walls in the corner and for whatever period of time, mold had formed and grown, giving me terrible sinus headaches.

Few if any home buyers realize or consider the serious consequences of a roofing leak or collection of rainfall around the perimeter of their potential purchase.  On a recent home inspection in Sea Ranch, the buyers were aware of a leak around the windows and were bracing themselves for rotten wood, mold, and extensive damage to insulation.  When I used my thermal imaging camera it was quickly apparent that the leak was actually starting several feet away at the peak of the roof.  Further inspection disclosed that there was no serious damage yet and the leak could be fixed at a nominal expense.


It is imperative that these items be properly inspected and reported on by the home inspector.  Inadequate gutters or debris filled gutters can cause water to back up and wick into the edge of roof sheathing, resulting in  rotten sheathing, fascia boards and rafter ends.  Standing water around the home's foundation allows tremendous quantities of moisture to seep under the foundation and then wick up through the concrete, both leading to serious consequences over the years.

Whether it's a leaking roof, a leaking kitchen faucet, leaking plumbing in the bathroom or under the house in the crawl space, you need to be aware.  WATER IS THE SINGLE MOST DESTRUCTIVE FORCE TO A HOUSE.  This is where the infrared camera can be an invaluable tool.  Do not make the mistake of thinking it's only a small leak and won't take much to fix it.  It could take thousands to fix what has been deteriorated or destroyed.


For each 1" of rainfall on a roof, there are 600 gallons of roof run-off water for every 1000 square feet of the roof surface.  Most homes have well over 2000 square feet or more roof surface area.  Lake County, Mendocino County and Sonoma County to name a few of the immediate surrounding areas have an average annual rainfall of 24 to over 75 inches of rain.  This is typically concentrated in a period of 5 to 6 months.

A 3000 square foot roof surface experiencing 25 inches of rainfall would have approximately 45,000 gallons of water runoff from the roof each year.  The reality is most 3 bedroom, 2 bath homes with an attached garage have more than 3000 square feet and most of the rainfall is more than 25 inches.  This provides a tremendous amount of moisture to seep through a hole in the shingles or around poor or old rusted flashings.  A leaking roof can and often does mean rotting sheathing and rafters.  Larger amounts soak the attic insulation, then the ceilings and even into the walls.  Interior moisture in ceilings and walls generally creates mold which for many is a serious health issue.  It is a huge amount of water seeping under your house if not properly controlled.  The end result is foundation cracking, shifting and rotting wood structure or mold.

Rain water must be contained and diverted away from the house.  If there isn't a viable way for the water to drain off the roof, it will back up under the shingles.  If the downspout does not have a diverter at the bottom to drain the runoff away from the house, the water will seep into and under the foundation.  All have the potential of causing damages costing thousands.  In extreme conditions where the ground remains soaked, the foundation may actually crack.  Gutters and downspouts need to be free of debris, of adequate size and in good condition.

If this aspect of the home inspection is overlooked by a less than qualified home inspector and many times it is, the consequences could be substantially costly.

In numerous instances a roof may appear to be sound when in fact it is leaking.  The only way to really know without tearing off the shingles is to have a THERMAL IMAGE INSPECTION.  This process will find the leaks and roof damage if there is any and it costs only a fraction what a roofing contractor charges for a tear off and shingle replacement.