What happened to the
window sill ?

Ask the pros-August, 2006
By Reggie Bullard





Window sill pitchedWindow sill
                  with drip grooveBad window sill design

Bottom pitched for            Bottom straight,
a drip                                drip groove keeps
                                          water from running back

Water running down will take it's course in deterioration in due time-look at the Grand Canyon. Also for stucco, brick or other materials that aren't waterproof water can soak through behind the wall prematurely deteriorating the material. Lack of groove or angled drip actually deflects water between the sill and the wall.
                    window sill
No sill at all on this EIFS dormer is asking for trouble-
No sill and the band are the Trend these days.
One argument I heard from an architect defending lack of sills on a multi-million dollar renovation is he wanted the "clean look".
What looks clean about soot and dirt running down and staining the
wall, or discoloration ? Also a wet wall promotes the growth of moss, and traps other airborn dirt and grime. 
No window sill Original house had window sill
New stucco addition we recently finished
had no sills on the plans.
The original house had sills, with
a drip groove and an angled bottom.
No sill Stucco addition on the house next door was done the same way-no sills even though the existing house had good sills. Note how water
runs right between the window and the stucco. I would guess this addition was built in the last 20 years, and the original house about 1925.
Unfortunately, I have very little control over the lack of sills, all I can
do is make a suggestion. It seems like not much work running off
some 2 x 2 or whatever lumber on a table saw and cutting to length
and nailing on the wall.
No sill Is this the "clean look"? No sill on this nice 
stucco installation is badly stained. A window sill could have pevented this.
Sometimes we make stucco sills, when directed, but stucco really isn't that reliable as material for sills or horizontal surfaces. The stucco really isn't that water resisant, and is subject to easy staining and discoloration.

In the future, we plan to put on a protruding flashing below the window,
like Mr. Bad Stucco has on his site.

                                    Stucco news home