1. The single largest misconception about stucco is that the water hits the surface and just runs off. Actually, since stucco is made up of sand and cement, it is porous and is designed to allow the water to pass through it. Once through the surface it meets the building papers behind and then drains downward and out the bottom through a "weep screed". (This is an "L" shaped flashing with holes in the bottom.) In stucco sided homes the moisture barriers are the building papers, window flashings, diverter flashings and foundation flashings.
2. The second misconception is that painting the stucco is a proper way to patch or re-color it. Paints, especially the elastomeric coatings, seal the surface of the stucco. However this does not stop water from getting behind the stucco. That's because 70% of the water that gets behind the stucco comes through the gaps around windows, doors or other penetrations through the stucco. With a sealed or painted surface, the stucco can no longer breath properly. Thus the water becomes trapped longer which leads to premature breakdown of the building papers and then the OSB plywood sheathing. Lastly, once the house has been painted or coated it can no longer be patched. This results in having to remove all of the stucco in order to make repairs. Obviously total removal is very expensive.
3. All stucco contractors are the same. This is not even close. Most are not up to speed on current codes, product changes or installation procedural changes. Many, if not most, are not licensed, insured and most don't carry Workmans Compensation. The lack of insurance's and licensing puts you at great risk, both in case of an accident or in the event of poor quality work. The up side is they are generally cheaper. Remember, "You Get What You Pay For".
SIGNS YOUR STUCCO IS FAILING
One of the most often overlooked signs is "black" streaks below a roof to wall junction. The most common place to find this is on the sides of a chimney chase.
These are not stains from a leaking rain gutter. The black represents broken down building papers and the coloring is now wicking through the cracks. The wall behind these cracks was totally rotted away as were the framing members.
Gaps around the window frame and wall framing at the interior is an excellent sign that the stucco is leaking.
These gaps are caused by water saturating the OSB plywood around the windows. As the plywood becomes wet, it begins to swell. As it swells it pushes the entire window assembly away from the interior framing. This will require removing the stucco around the window, replacing the damaged OSB and installing new stucco at the exterior. This condition is mostly found in homes built prior to 1999 as dedicated window flashing was not required until 1997.
PROPER METHODS OF REPAIR
Damage, like shown here, requires removal of the stucco both vertically and horizontally until dry material is found and dry studs are reached. The damaged materials (stucco, building papers, plywood, insulation) are removed and replaced with new materials. New stucco wire, base and color coats are then applied. You will want to color all adjoining areas (corner to corner and top to bottom) to ensure a good color match. Stucco color can be matched quite well but there is no way to match surface degradation caused by the weather and UV rays. Therefore just patching a small area will look like a patch and be very obvious.
Repairing leaking windows requires removal of the stucco (min. 5") around the window. The window must be pulled out, new window flashing is then installed around and inside the window frame. The window fin is then caulked and the window screwed back in place. New building papers are then woven into the window flashing, a foam 4"- 6" pop-out trim priece is installed. The trim piece is then covered with wire, a base coat and then the color coat. Note: It is often necessary to remove a lot more stucco if the plywood is damaged or swollen. Unfortuately, the degree of damage cannot be fully determined until the stucco is actually removed.
Most stucco contractors are not qualified to perform all of the structural repairs that may be necessary when repairing leaking stucco. Our crews are experts in performing all the necessary repairs that may be necessary.
Once again, "You Get What You Pay For".