Why Do We (obsessively) Tape?

A couple of years ago I wrote a blog on the importance of properly managing moisture in high performance homes.  There, I made the point that proper flashing and taping are a big part of that management process.  I really believed that back then.  I really, REALLY believe that now. 

The house at the time of sale.

 The house at the time of sale. Nothing to suggest the mess festering inside.

We are currently working on a project in a remote area of the Berkshires.  Our clients had bought a cozy house with a glorious view.  They found the house a bit too cozy, so they came to us to put a second story addition on it (and, of course, fully electrify it and improve its comfort and energy performance).  We drew up plans, got our permit and jumped on demo.  What we found during demo was terrifying.

The slow, surgical demo begins.

The slow, surgical demo begins.

Blackened, delaminating plywood

Whoa, this doesn’t look good! Blackened, delaminating plywood—always a bad sign.

New “structural” picture window holding up the roof.

This must be one of those new “structural” picture windows, ‘cuz nothing else was holding up that roof.

Prior to demo the house appeared to be in top shape.  The inspection report at the time of sale offered no hints as to what we were about to find behind the tidy finishes.  As we started to surgically demo individual walls that would be in the way of the addition, we started to find some fairly serious rot.  Initially, we were all a bit relieved in a self-congratulatory kind of way: “Thank God we found this rot now!  And what luck! It just happens to be in a wall we’re going to rip out anyway,” we commented.  Well, the relief and sense of luck didn’t last long.  As we dug in further, little by little, we slowly and painfully reached an inescapable but dreaded and dreadful conclusion.  We need to tear the whole thing down and rebuild from scratch.

House is mostly demolished

Hey boss, time to cut our losses?

Final stages of home demolition

Fugettaboutit!

New house under construction

The rising! It’s the start of a new day.

So, what went wrong?  The pattern of the rot said it all.  Poor flashing details (or in some cases, no flashing details) around windows and doors had allowed water to completely rot away a seventies-era built home.  This didn’t have to happen, and we won’t let it happen to this house again.  We put protective tape over the entire rough opening of every window.  We also taped the around the window flanges and created a venting space between the siding and the rigid insulation, so that any water that gets behind the siding has an easy way out and any that decides to hang around will get dried out by air circulating through the vent space.  This is the kind of belt and suspenders and another belt that keeps wood framed structures dry and long-lasting.

New house to replace the original

We blew through our flashing tape budget on this one.