Keeping Water Out of Stucco Walls

Shown here is a shutter block that was installed on top of a piece of light-blue self-adhered flashing. Unfortunately, the building paper was then installed on top of the flashing beneath the block, which allowed water to run behind the paper and soak the framing.

In the repair, the flashing membrane sits on top of the paper below the block.

This window’s bottom flange was taped to the sheathing. Trapped water caused the flashing membrane’s adhesive to fail, directing even more water into the framing.

Wrinkles in the membranes can also create water paths underneath stucco, as in the wide sill of this recessed window.

Prefabricated plastic corners ...

and flashing tapes and membranes simplify window and door installation.

Always use a roller when installing self-adhering membranes, to get rid of wrinkles.

This wire lath has been installed backward; it should be positioned so the ridges hold it away from the wall.

The author advises against using staples to attach lath, because the holes they make in the building paper tend to become elongated.

Furring nails are preferable; they have a cork washer that holds the wire off the paper and also seals around the shank.

Stucco crews often use their hatchets to bend the lath in inside corners, ripping the building paper in the process. It’s a good idea to line corners with self-adhering membrane before installing the paper.

The open slits in the upper leg of this poorly installed weep screed allowed water to soak the framing.

This wall has been repaired and is ready for stucco. The upper leg of the screed is behind the building paper as it should be, but there is not enough clearance to grade.

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