House Washing

I’m sure you’ve heard the expression – If it’s green, it’s time to clean!

Over time, dirt, filth, mold, and algae can build up on the external surfaces of your home. This can result in premature damage.

The financial impact of replacing something is usually more expensive than fixing it. Repairs can cost up to ten times what cleaning at regular intervals would have cost.

External mold degrades wood surfaces and eats away at stucco and other materials. Over time, this causes significant damage to exterior surfaces.

Mold algae and fungus accumulate and act as a sponge. This provides a perfect moisture source for their growth. The moisture used by mold and fungi will find its way from outside surfaces to inside structures.

Your homes exterior is its most important line of defense against moisture intrusion. Penetration of the exterior surface can provide a pathway for water to wick. Wicking from exterior sealed surfaces to unprotected interior structures can cause major damage. As a home inspector, I saw many examples of significant structure deterioration. This damage can become extensive in a short amount of time.

Internal wooden structural components consist of standard lumber. Wood, especially moist wood, will swell and shrink with extreme temperature ranges. Here in the Southeast, we see variance in temperature of sometimes 40 degrees in a single day. Because of its cost, pressure treated wood is not used for internal wooden structure. Because of this, these structures rely on the moisture protection envelope.

The buildings moisture protection envelope consists of several components. This starts with the roof. Moisture from rain and dew sheds down the shingles to the gutters and siding. Sealing gaps in the siding prevents moisture from passing through to structural components. Water that sheds from the siding to the ground gets carried away by the slope of the perimeter grading. Along with the grading slope, a swale or depression provides a place for the surface water to drain. The effect is to draw water away from the building preventing pooling and wicking. This is also the reason that inspectors will report on plants and vegetation. When plantings are close to the foundation, it can have the effect of allowing water to pool. This could lead to wicking through the sill and contact with internal wooden members.

In my own home, I found the cause of one of my roof rafters rotting. I found a nail protruding under a roof shingle where it wasn’t visible. Water penetrated along the nail causing it to rust. Water wicked through the roofing underpayment into the roof truss. After 5 years, the rafter had rotted a little more than a third through its width which was a little over 2”. The same effect happens with areas where water collects and seeps into the interior.

There is an interesting article by the Liberty Building Forensics Group. It mentions various causes of moisture intrusion in a buildings envelope. According to the article, Atlanta is not considered a humid climate. The article states “Atlanta, Georgia, for example, does not qualify as a humid climate under the ASHRAE definition, but high dew points are experienced in this area and problematic buildings are often found there.”

I for one need to remember that next summer in the “Hotlanta” heat! 🙂

How often should you clean a house?

This question gets raised at times with my customers.

-It makes sense to clean homes at least every 1 to 2 years, Based on the climate our home exteriors are in. Depending on what direction your home faces, you may need Spot cleaning. This is due in part with northern exposures as they stay moist longer during the day. Shady areas may need more attention as well.

– After a point, no amount of cleaning will remove the stains and the surface will need repainting.

-Removing pollen and contaminants, especially on tin roofs, can prevent premature failure. Pressure washing is not recommended for any roof. It’s too dangerous and can cause damage to roofing material. We can help by removing mold, algae or mildew with softwashing equipment. Refer to this list of cleaning recommendations for metal roofs. This is a great article by metal roof manufacturer Sheffield Metals.

Why not wash the house myself ?

A professional can help to avoid damage caused by pressure washing. High volumes of water allows reaching upper levels of a home. A professionals equipment design affords the ability to reach areas consumer equipment can’t. It’s not only about the amount of pressure, but the volume of water that the equipment can move. To best clean mold, mildew and algae from the homes surface, requires the correct chemical mix. The mixture a professional pressure washer uses is of a much higher concentration. This is for a few reasons;


  • It takes less time for the higher concentrated solution to kill organic material. This translates into less cost for you. As the old adage goes – time is money!
  • It lasts longer – The chemical mix used by professionals penetrates deeper. By killing the roots of the organics, the cleaning lasts longer.
  • Different solutions depending on the organic matter. There are different types of organisms that need different compounds to kill them. An example of this is lichen whose definition is a composite organism. This is several different species in a mutualistic relationship benefiting each other. Lichen are more difficult to kill and requires stronger solutions. Stronger solutions will have an affect on the surfaces they come in contact with. Professionals know how to mitigate this affect and prevent associative damage.

A consummate professional avoids damage to property or plants. Using higher concentration solutions to kill organics can cause collateral damage to plants. This can ruin your hard work planting ornamentals and landscaping. Always ensure professional insurance is in place!


Professional insurance protects you against damage to home and health. Using high pressure equipment can damage home surfaces. Use of high pressure can cause serious injury! It’s important to understand and be familiar with tools to prevent injury. This is difficult when renting equipment for a couple of hours. If high pressure can blast dirt away – imagine what it can do to your skin! (I have stories…)


It’s quicker for a professional

Professionals have done it before and have a routine down to resolve issues as they occur. They have the right equipment. The right equipment can get pretty expensive depending on what needs cleaning.

You can save a lot of time hiring someone to do the job versus running back and forth renting equipment. There is also the task of determining and buying chemicals. If you opt to buy the equipment – it comes with its own set of issues. It will need maintenance and storage. There will be research involved as well for your cleaning needs.

Why wash your house – doesn’t it already get a bath in the rain? 🙂

That’s a great question. Although your home and property gets “rinsed” in the rain that can come with its own set of problems. This publication from the EPA discusses some of the effects of acid rain. This article mentions the affects of dry deposition. This contributes to decomposition of man made structures.

Suffice it to say, your house is not getting a bath when it rains. It’s more likely deposits which deteriorate your homes surfaces are landing on it. Additionally, houses in the Southeast experience pollen baths each spring. This carries along with it more dirt and grime as well as destructive contaminants. These deposits land on your home leaving it in a desperate need for a cleaning!

Part of the makeup of contaminants in the air come from airplane fuel. We are close to the busiest airport in the world after all! I remember working at an office by Dobbins Air Base early in my career. We would have to clean our computer monitors on a regular basis. After wiping, the cloths would be black with soot. In the Southeast, contaminants, suspended in water travel with humidity droplets. There are plenty of reasons to wash your house every 1 to 2 years!

There are many benefits to a clean home exterior, here is just a brief list:

  • Removal of organic growth which minimizes deterioration of exterior surfaces. This reduces the cost compare to replacement by up to 10 times!
  • If you stay on top of it – there is less accumulation to clean. This is the main reason I offer yearly or biennial contracts to my customers.
  • By maintaining regular cleaning you lessen the destruction that could go unnoticed otherwise.
  • It’s easier to clean and, there is less opportunity for staining of the painted surfaces. Once stained, a painted surface needs repainting to restore it which comes with a higher cost.
  • You won’t have to paint as often as the paint can actually last longer.
  • Many customers delay getting their house painted and then not as often.
  • Delaying a paint job saves you money right away if you delay and more over time by having to paint less.

Is a clean house worth more?

Are you considering selling your home ?  If so, you may be able to make more on the sale by cleaning the homes exterior.
  • It can bring more money on the market. Perception is reality to a lot of people. Dirty houses represent neglect in some opinions and may trigger discount requests from the potential buyers.
  • Prolonging maintenance can expose wooden surfaces and lead to damage. Damage costs mone