Readying the wall for flashing

Thursday, May 19:

We have had sporadic showers the past few days that are making the outside wall damp – though the plastic over the scaffold is keeping direct rain off of everything.  I am waiting for a warm, dry day to begin installing window flashing and a moisture barrier on the outside wall.  Meanwhile, this morning I chipped a little more stucco around the top corners of the lower window and cleaned up that window's top edge.

To gain access to the top of this plate-glass window, I had to temporarily remove one of the scaffold boards. Now I have to be careful not to drop a hammer onto the glass – or worse, fall through the opening!

I chipped the stucco down a few inches below the top edge of this window.  This will allow me to lap new flashing over the existing paper barrier. I plan to smear black asphalt roofing cement over this old paper and glue the new flashing to it. 

Some blowhard worker at Home Depot told me just to use caulk – that roofing cement would be "overkill."

"I probably installed 500 windows as a carpenter, and none ever leaked," the guy said. 

Of course, my experience with contractors is that they are long gone by the time a window starts leaking, especially in a place like California – where one can go six or nine months with no rain.

Why take a chance? The paper barrier is asphalt-based.  The new flashing is asphalt-based.  It makes sense to me to use petroleum-based asphalt-cement for a really good bond.  Sure, it's messier, but I am only doing this once. I can use rubber gloves.   If I did this for a living, I'm sure I'd be just like Mr. Home Depot Know-It-All and use caulk, which would be less messy and much faster.

To get the surfaces really clean, I had to vacuum out all the tiny stucco chips that had fallen down into the cracks.

The flashing will lap down into the channel-frame of this window. Therefore I had to get it as clean as possible by removing old paper barrier scraps, staples, nails, stucco mesh and caulk.