Look Good and Last longer
Roof cleaning serves two functions restore the look of a new or almost new roof. Secondly prevent premature failure due to trapping too much moisture on the roof from retained debris and also growth on the roof that also holds moisture on the roof. I have noticed from customers these are the prevelant motivations. Some people are realy bugged by looking at a dirty dingy roof and some others could care less. If you have found this site and it does bother you when the roof is looking bad call me. Some roofs I have cleaned that have been dirty for a long time and in the shade the shingles get a little spongy. The roofing material is built to be water proof buy why not help keep foreing things off it or growing on it. Why push it?
Why A Roof Grows Moss
Setting the scene. Roofs do not completly shed everything that falls on them. During the year a lot of tree seeds and leaves fall on a roof. Not all of it is shed from the roof. The granuales that protect the waterproof surface of the roof are course and small organic particles tend to collect some organic material. The organic material will hold more moisture longer than a clear clean roof.
The second factor. Too much shade. Typically under trees more debris will fall on the roof below so a lot of stuff is on the shingles other than grit. The angle of the roof relative to the sun keeps shade on the roof and relativly more moisture longer on the roof. These two factors iether seperatly or together create a situation that over wellms the ability of the shingles to stay clean and free of discoloration or growth. Most shingles have material built into them that helps prevent mold and mildew from forming on the roof. But as organic material builds up on the roof the discoloration can start. It is truely amazing what can stick in the cracks and crevasis of a roof.
Moss Feeeds on The Debris
One particular place debris accumulates is at the lower edge of the shingle. Then moss can form on that edge. The moss holds more moisture on the roof for its self to survive and creates an environment for mold to grow. Moss is designed to grow on rocks and can survive in that environment so over the years as stuff accumulates on a roof with some food to live on the moss starts to acumulate. As the moss goes through its life cycle of growing and dying it alos supplies more stuff stuck to the roof holding moisture for more growth to develop.
Black Mold On a Roof
The same factors that cause moss to form provides an environment for black mold to get started on a roof. With too much dirt and organic material on the roof the material in the grit to prevent to black mold just can not keep up with it. So the black streakes develop and get bigger and darker till the roof is cleaned. Over time and with the right weather the dark black color can be impressive.
Lichen on a roof
Round blueish green spots on the roof is lichen. This tenacious primitive plant clings to the roof like an oyester to a rock. The other sign of lichen are the dark spots on a roof where lichen formes and then died. Left behing is a spot where the roof granuals are missing and the bare black shingle is expossed. So the roof starts to look like it has black blotches on them. Lichen seems able to grow on rocks in almost full sun, so the roof is a place it can also handle. Many trees around a house alos have lichen growing on the trunks and branches of the trees so it spreads to the roof from there. Mechanically removing lichen from a roof is hard to do without damaging the surface. My cleaning process is to rub or brush off what is loose and kill the rest. It dies and falls off over time.
How we clean a Roof
The process is ladder intensive and labor intensive. I remove all loose material from the roof by brushing or with a blower. Then the dirty areas that have moss or lichen particular attention is paid to brush off what ever can be cleaned mechanically with out too much pressure that will remove to much roof grit. Each roof has a slightly different degree of tenderness to loosing grit, so the effort is adjusted accordingly. Here the goal is to get the roof cleaning material to the surface so it will work.
The cleaner solution will kill the moss, black and green mold, and the lichen on the roof. It is sprayed on with a pump up sprayer so it is like a light mist or rain on the roof. I do not use pressure to blast the roof to clean it. This gental application of cleaner changes the balance of power to the roofs favor. What ever was not removed mechnically now will get killed and fall off over time. The strength is adjusted so it is just strong enough to kill the growth and no more. A smooth consistant application is put on the roof and the surfactant (soap) in the mix foams up and holds the cleaner on the roof. Moments after the cleaner is applied the green moss turns white, the black mold turns a light brown and the lichen turns a whiteish brown. This shows the cleaner is working and killing what ever is on the roof. With a couple of rain storms it washes of what was living there so the roof now is bright, clear and clean again. Often small dead clumps of moss may remain. They look like tufts of small white cotton balls. The other thing that remains are dead circles of lichen that break down and fall off with out the need for sraping them off and loosing a lot of roof grit.
Protect the landscaping
Very specific focused application of a controlled spray keeps the cleaner on the roof and just the roof. Any places that the spray may drift to and damage is wet prior to application and then rinsed after application of the cleaner. So no burning occures on the foliage. Leaving the cleaner on the roof insures I will get full afect of the cleaner and over time it is deactived by sunlight. This way when it rains no toxic material goes down to the landcaping and lawn.
Follow up if Needed
Some times heavy growth on the roof just does not come off for any number of reasons. Occasionally some black spots can remain and have to be retreated. This is included in the service and I am happy to reapply so the roof looks consistant. For lichen this is not included since it takes time for it to die and fall off. But the color change is indicative to show it is dead since no photosynthesis can occure. When it breakes down and falls off it releases its grip on the roof grit. To blast it off would cause more gri and spotting on the roof
Have a Dirty Roof?
If you have this problem call me for a price to do roof cleaning for you. The difference you will see is dramatic initially and even cleaner after a couple of rains the roof will look almost new other than normal wear and tear of time and age. Quotes are free and binding call 203-906-6079