In one of the great mysteries of the building universe I have come wonder why things have gotten the way the have.

When performing home inspections I constantly reminded the caulk is not a good flashing and should not be used as one. These are high maintenance joints/transitions.  So why is the over use of caulking so common? Is that we are either lazy in thinking, have poor building practices, or have some odd sense of cost versus benefit.

                 ( Properly flashed and failure from lack of flashing and maintenance )

I do many different types of inspections from, phase inspections, draw inspections, one year warranty inspection and yes existing home inspection and from this I see many building practices, some good and some very poor.

Here is from a common building material installation guide-

“CertainTeed highly recommends the use of flashing to ensure a long-lasting, weather-resistant installation.”

Do I see highly recommends using absurd amounts of caulk to perform as a flashing? No I did not.

And why does the manufacture just come out and require flashing versus “Highly Recommend”

Certainteed installation guides- http://www.certainteed.com/resources/fc017.pdf

Here is a installation instruction from LP. Notice it does not show caulk over the window or openings..

Lets just assume to the flashing cost about $.35 a linear foot and halfway decent caulk is about $.17 a linear foot. Then we have installation, which I think installing a flashing is actually quicker. So the cost difference per foot is probably when all said and done is negligible. Then you have the eventual maintenance factor then caulking is always the poor choice from a cost standpoint, let alone is still is not a flashing.

So why do we keep doing this? Then we have that thing called the code-

R703.8 Flashing.

Approved corrosion-resistant flashing shall be applied shingle-fashion in a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. Self-adhered membranes used as flashing shall comply with AAMA 711. The flashing shall extend to the surface of the exterior wall finish. Approved corrosion-resistant flashings shall be installed at all of the following locations: (See code section for details)

Again I do not see use caulk as a flashing there either.

( An example of good flashing technique )      

So when does this all stop? I think it really needs to come down to the building officials to put an end to this. Sealants/caulks have their applications but should not be a substitute for a proper flashing.

Here is a link to one flashing manufacturer showing most of the flashing details you ever should see. http://tamlyn.com/images/pdf/Xtreme%20Trim%20Catalog.pdf  

“If you think it's expensive to hire a professional to do the job, wait until you hire an amateur.”

Red Adair

NCW Home Inspections, LLC  is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…  

Your Wenatchee and Chelan Professional Real Estate, Home and Structural Pest Inspection Service

www.ncwhomeinspections.com                                                   509-670-9572