What Goes In, Must Come Out

There is nothing I can think of that has an infinite capacity on this planet. Sooner or later, if something is put in, the vessel reaches capacity and something must come out or a failure will occur. One example I use quite frequently as a home inspector is with regard to forced air type heating systems. For these types of systems to operate efficiently, not only must they “force” air into the rooms, it also must be removed at the same time. If the air is not given a way out, the system operates almost like a person trying to blow air into a bottle.

There are less obvious places in buildings where the in and out principle not only applies, but if not in place can cause, as I said, a failure.

I was reminded of the need for a way out on a job not long ago. I was contacted to investigate a failure of the cladding on three buildings built in 2004. The siding was fiber cement, a good durable product that takes paint well. The paint started peeling off the new cladding on the three buildings about a year after construction was completed. The cladding itself was also deteriorating which was certainly related to the failing paint.

Houses are protected from exterior water infiltration basically by layering. The first layer is building paper, the most familiar is probably Tyvek. Before Tyvek tar paper was used. The second layer is flashings around penetrations like windows and doors. Lastly the cladding is installed.

The building paper serves to protect the wood sheathing beneath from incidental water penetration. What many people do not realize, this would also include some contractors, is that all cladding leaks. When water does get behind the siding, the next important consideration must be to provide it a way out.

Remember what goes in, must come out.

What I noticed on the building I was inspecting through the infrared camera was not only water behind the cladding, but a concentration of moisture at the base of the walls.

Another principle to remember, gravity.

Checking the base of the wall with a moisture meter where the siding meets the trim, I found it to be saturated basically confirming the thermal anomalies to be moisture.

What I noticed when checking various spots along the wall base was I had to work to get the meter into the seam. There was no gap. I noted the same above windows and doors. Without the gaps, the water has no place to go and thus there can be no drying. By omitting this simple but important detail, the cladding and paint has been deteriorating for close to eight years.

You can’t alter physics.

James Quarello
Connecticut Home Inspector
Former SNEC-ASHI President
NRSB #8SS0022
JRV Home Inspection Services, LLC

To find out more about our other high tech services we offer in Connecticut click on the links below:

Serving the Connecticut Counties of Fairfield, Hartford, Middlesex, New Haven, Southern Litchfield and Western New London.