Clean Stained Siding Before Winter


Stained Siding | Madison WI | Sims Exteriors & Remodeling
After months of warm, wet, humid weather unsightly stained siding is showing up all over southern Wisconsin. Some stains are just ugly, some are dangerous – knowing what you have is vital.

Unsightly stained siding is showing up on the north side of homes throughout the Madison WI area. Mostly green or green-tinted with black, the stains are usually mold, mildew, algae or moss. Or a combination of all of these life forms. Staining is especially a problem during extremely wet, damp and humid periods – like the summers of 2018 and 2019. The stains are all natural. Appearing where the house gets the least exposure to intense sunlight, they make all siding look old and ugly. They damage some forms – especially older siding materials.

Almost always an appearance concern on aluminum and vinyl siding, these elements damage wood siding. If you have wood or composite siding, mold can penetrate the surface and eat away at the surface. Once it gets inside the surface it spreads.

Causes Of Stained Siding

In most cases, the dirty green stains are from one of two sources:

  • Mold – water dripping onto the area or staying put long after rain stops is the main cause of green mold on siding. Rain and extended periods of humidity with no heat from the sun keeps the surface damp. Leaking and overflowing gutters also contribute to the problem. Taking action early, removing mold isn’t too hard. Once mold gets a foothold, it takes professional treatment to safely treat it.
  • Algae – most people think of lakes or ponds when they link of algae but it will grow on any damp surface. Algae on building surfaces appear in two common forms: green and brown. Unlike mold, algae seldom damages siding. Algae growth is aided by the buildup of dirt and dust on damp siding – often blown around in storms.

Unless you’ve dealt with stains like this before consult a professional inspector to be sure what you’re dealing with. A Sims technician can identify the source of the stains and prescribe an appropriate treatment. There are treatments to remove stains and additional treatments to prevent it coming back. In extreme cases siding has to be repaired or replaced.

Be On The Lookout For

Stained Siding | Madison WI | Sims Exteriors & Remodeling
Areas shaded from sunlight and poorly ventilated are prime locations for mold, algae and mildew to thrive.

Stains on siding are “color-coded.” The color of a stain on your home provides clues to what’s beneath it. The color variations you might see include:

  • Brown stains – especially on older wood and composite siding, brown stain signals moisture underneath the wood.
  • Black stains – most common sign of all the major concerns: algae, mildew, mold and fungus.
  • Green stains – almost always either algae or moss. Most often in areas with poor air circulation and limited exposure to sunlight.
  • Yellow stains – showing though siding indicates potential problems with insulation and sheathing under the siding.
  • Matching the siding color – usually just dirt and grime caused by water running down the surface from damaged or misaligned gutters. No serious on their own these stains are indicators that the surface is ideal for mildew and mold.
  • Rust-colored stains – a sign of water beneath the siding that’s rusting nails. Especially shows up on older wood and composite siding.

Vinyl Siding Is Tough

Vinyl siding is tough and resilient. It is the No. 1 choice for residential siding across the country. However, it isn’t perfect. It must be kept clean. It accumulates all kinds of dirt, grime and natural stains from things like wind-blown pollen, insect and bird droppings and spider webs. The molds, mildew and algae move into shady damp areas. The polymer makeup of vinyl siding can be impacted by misapplied or wind-blown insecticides, herbicide and fertilizers. Because of chemical interaction, the surface can be weakened. Weak spots give molds a place to grab hold.

There are dozens of commercial products advertised for cleaning vinyl siding. Some promote mold, algae and mildew removal and protection. Some do not. The Vinyl Siding Institute offers tips for cleaning and maintaining siding. It’s a fairly easy job on a routine basis.

For everyday dirt and grime, simple solutions are the best choice. Treating algae, mold or mildew takes harsher chemicals. These treatments come with side effects. Many siding cleaning solutions are dangerous to landscape plants. Additionally, choosing the wrong chemicals can stain or damage aluminum, stucco and wood trim. The source of the stains dictates the best cleaning agent.

Advances in technology make pressure washers available to homeowners. A pressure washer seems to be a natural tool for cleaning siding – and in the hands of a knowledgeable user it is. Many siding makers advise against using a pressure washer. All agree the key is using limited pressure. Pressure washers at high pressure can open cracks in siding you never knew were there – causing extensive damage. They can also “blast” away vital caulk and drive water under siding. Water under siding is a breeding place for mold.

Consult Roofing And Siding Pros

Are stains on your siding and roof just ugly? Or are they more of a threat? You cannot tell just by looking at them. Because they have years of experience and training, siding and roofing installation professionals do have an edge. What do they look for:

  • Threats to family health – algae and mold produce toxins that cause serious reactions for people and pets. You’ve, no doubt, heard of swimming areas in lakes closed down because of algae “blooms.” Mold is the No. 1 concern for home inspections when property is up for sale. Mildew causes skin irritations and allergic reactions.
  • Warning Signs – stains don’t automatically mean there’s a deeper problem. But because they’re present moisture could be trapped underneath the siding. That means the weather barrier beneath siding is at risk – in older homes there may not be one. If it’s damaged, missing or installed improperly moisture can enter the interior of the house where the barrier is weak.

Working with a contractor with decades of experience and access to all the latest technology is the best way to make sure your home and family is safe. Few companies match the experience and expertise of Sims. Our veteran pros couple industry-leading products with timely service and problem-solving ability.

Do you have unsightly stains? When you are ready clean up the stains and protect your investment call Sims Exteriors & Remodeling at 608-825-4500 or email us. We have the latest products to fight mold, algae and mildew on your stained siding in Madison WI.

Sims Siding 

Cleaning Vinyl Siding – Vinyl Siding Institute

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