What is the Cause of Southeastern Pennsylvania’s Stucco Siding Crisis?

Southeastern Pennsylvania has been experiencing an epidemic of damage to its stucco siding homes over the last several years. The telltale creeping black stain is unfortunately more than just an eyesore. The cause is wall rot, and far from being superficial, it is usually a result of extensive mold growth in the supporting layers behind the stucco surface. Unfortunately, most homeowners don’t realize that there’s a problem until the overgrowth has progressed substantially.

This expensive and unsightly problem is caused by moisture intrusion due to substandard installation practices. When a stucco surface is properly prepped, a multi-step process involving asphalt paper, a rain barrier with a permanent air gap, and a mesh layer are applied prior to the stucco layers. To protect the areas around exterior windows and doors, flashing must be professionally installed to create a watertight seal. It goes without saying that proper installation requires expertise, time, and the right materials. Inexperienced contractors who rush through the job or try to save on materials are bound to create a nightmare for homeowners, even just a few years after their work is completed.

The Damage Caused by Trapped Moisture

Stucco is a highly absorbent material, hence the tendency for problems caused by trapped moisture. A common effect of dampness is called “stucco tears,” streaky stains that appear on the stucco, typically extending downward from windows. Moisture, of course, causes mold and mildew to grow; left unchecked, it can lead to an overgrowth of black mold.

The issue behind much of the recent damage in Southeastern Pennsylvania is wall rot. When moisture creeps into stucco and the layers beneath it, it can lead to extensive rotting deep into the walls of your home, even to the OSB sheathing and 2x4s. Wall rot can cause severe damage, even rendering your home structurally unsound.
Unfortunately, issues with trapped moisture may not be visually apparent until extensive damage has been caused to your façade or to the structure of your home.

Keeping Moisture Out

Your stucco siding is in constant contact with the elements. Because stucco is so vulnerable to rain, it should be installed with a rain barrier, which allows the surface to breathe. Waterproof building paper and flashing should be installed around windows and doors. Kick-out flashing is necessary when the lower part of the roof cornice stops in the middle of a stucco wall or if the roof line does not extend below the while.

Weep screeds, another material that allows moisture to escape, are employed at the lower edges of the structure to allow water to drain. It is never good practice to extend stucco into the ground. Gutters can be placed to divert water away from areas that are particularly prone to trapping moisture, and if kept clean and clear of debris they will support moisture removal. The most important factor in defending against moisture intrusion is proper installation of all layers up to and including your stucco siding.

There are some practical measures you can take to discourage the accumulation of dampness in your stucco siding—these won’t change the underlying structure, of course, but they can help prevent wall rot and other ill effects created by moisture. Planting trees and shrubs at a sufficient distance from your stucco so that leaves and branches stay clear of the façade is a good idea, as it will prevent the formation of a “pocket” that can wind up collecting moisture and funneling it toward the home. By now, it should go without saying that a pressure washer should not be used on a stucco façade. If the stains you are pummeling with water were caused by moisture in the first place (and they probably were) you will only be encouraging more mold growth.

Diagnosing the Problem

Mold and wall rot are insidious problems that can take root before a homeowner even suspects there is a problem. As discussed above, “stucco tears” and other patches of black growth can indicate a moisture problem. Vulnerable areas include windows, doors, and the intersections of walls with the roof. If you’ve noticed wetness around the edges of wall-to-wall carpet or the smell of mold, you may unfortunately be the victim of wall rot. Rotting window sills or condensation on interior walls may also signal a wall rot problem.

Correcting Wall Rot

If you suspect a moisture problem, it’s important to get a professional evaluation right away. Be assured that the longer you wait, the worse your problem will become. A knowledgeable masonry contractor will use an infrared diagnostic tool to determine the extent of the damage and will be able to recommend a remedy. Depending on how many layers beneath the surface are affected, you may require anything from a basic resurfacing to a replacement of the entire wall. Check with your homeowner’s insurance policy to see what remediation services may be covered.

Stucco Today—Remediation Experts

If you live in Southeastern Pennsylvania and suspect that your stucco home may have sustained moisture damage, don’t panic. It is important for your peace of mind that you have the problem evaluated, and no matter the extent of the issue, there is a way to fix it.

At Stucco Today, we have nearly 30 years of experience in installing and remediating stucco siding. When you work with us, you know that we bring our extensive knowledge and expertise from day one until the job is finished to your satisfaction. We can save you thousands of dollars in repairs by catching a wall rot issue early.
Our proprietary 6-layer approach solves your mold or wall rot problem once and for all, eliminating the problem and protecting your investment from any future damage. Call Stucco Today to schedule an evaluation. We’re ready to discuss your options and ensure that your home is safe, structurally sound, and protected from the elements for decades to come. We’re looking forward to serving you!

Schedule an inspection of your home’s siding or request a quote today!