Bradly Lewis Home Maintenance INC   503-481-8872

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Roof Moss Removal Service around Portland Oregon

Asthetic Reasons for Roof Moss Removal Service

1. You are moving and want the house to look good when it goes on the market
2. You spouse, friends, neighbors and/or relatives comment on it and it becomes problem, a source of stress and/or embarrasment.
3. You get tired of looking at it and/or thinking about it

Financial reasons for roof moss removal

1. You are refinancing your house and the bank is going to send out a home inspector. And you want it to look as nice as possible.
2. Accumulations of roof moss are causing water to back up in valleys or flatter roof areas and causes the roof to leak
3. Clumps off moss roll off the roof and clogs the gutter way, causing the gutters to overflow at a lowpoint and jeopordize your foundation.
4. It plugs the downspouts and causes the problem of gutters overflowing and flooding your basement.
5. Your insurance company tells you to remove the roof moss or they won't renew the home owner policy.
6. A home inspector tells them the roof moss is a problem and that it must be removed before the house can be sold.
7. Moss continues to hold moisture against the roof and slows the roof from drying out after the rains.

Sheets of moss being removed from a 3 tab roof prior to moss treatment service. Photo by Brad Lewis, Portland Oregon USA

Technical reasons for roof moss removal

1. Sheets of moss on composition roof are almost completely covering a roof that is to be treated.
2. You cannot see the roof to know what shape it is in
3. Moss holds dirt on the roof that other plants feed on. This moss and dirt holds moisture.
4. Moist roofs that go through the freeze and thaw of winter will lose more granules than drier roofs.
5. Moist roofs tend to grow algae and mildew which leaves dark stains on the roof.
6. Eventually larger clumps of dead moss that has not been removed will decay and provide fertile ground for new moss to grow. Please note that moss that has been treated with zinc (which I use) will not spring back to life and is very difficult for new moss to grow in. However moss may in grow on top of dead moss in more extreme cases of high humidty, rainfall, inadequate roof drainage and roof shading.

The Best Time to Remove Roof Moss

The best time for roof moss removal is after the moss has been dead for a few weeks. If you remove moss while its alive, then it will damage the roof and the removed moss that falls in your landscape may start growing there. Dead moss that is being removed from the shingles will break up into a powder and not harm the granules on your roof. How soon you can remove the moss from your roof depends on how long its been killed, the current weather, how big a hurry you are in and how much rain and sun have hit the roof after the moss was killed. See moss treatment about treating the moss.

The Best Way to Remove Moss

There are at least five ways to remove dead moss from your roof and they each require different tools and a different process based on the amount of moss, roof pitch, and other variables which I've roughly outlined below.

Blown Off and Weathered Off

If there isn't much moss, it can be blown off with a blower. Depending on the species of moss, how long its been dead etc, about 60-80% of the moss will come off this way. This is advantageous because you roof may be blown off yearly anyway when you have your gutters cleaned. This is another advantage of keeping your roof cleaner by treating the moss before growth becomes heavy. Blowing off the dead moss should be done on a dry day.

Weathered Off

Weathering of the dead moss is another way that moss can be removed. If your roof faces south, or North (but at shallow pitch) then it will weather off quicker. Dead moss comes off quicker with more wind and hot/cold, wet/dry cycles. If a tree is shading your roof, then the weathering action will be substantially less. If your dominate weather patters come from the side of the roof that your dead moss is on, then the moss will weather off quicker. If dead moss sits on your roof too long, it can hold moisture and cause algae to grow. To my knowledge, algae does not damage roofs, but it doesn't look attractive. If you have algae growth, it may go away if the dead moss is removed. The roof can also be washed if you have algae growth.

Brushed Off

The remaining chunks can be removed by hand with an offset brush. Brush removal results in about 90% of the moss being removed. When ~90% of the moss is removed, the roof looks good from the ground. The finer pieces can be left to weather off the roof. The finer pieces are mostly dirt. If you want ~99% of the moss removed, then you should consider roof washing. The advantage of brushing off the moss over roof washing is that it's cheaper and doesn't make mud (dead moss and water). Also, brushing off the dead moss does not remove the zinc treatment. Zinc treatments usually last about a year, but it may be 3-5 years before moss will start again.

Roof Washing

Another option for removing stains and grime in addition to the moss is through roof washing. I offer this service also. But I recommend that you wait some time before washing the roof (don't pressure wash) because washing the roof will remove the majority of the zinc from the moss treatment. It's best to get at least one year out of the zinc treatment before washing your roof. This gives you the most value for your money. Roof washing uses a quite a bit of water and more time. It costs more than brushing off the roof, but not a lot more. Roof washing can be done during wet weather. See also roof cleaning

Moss Removal Prior to Treatment

If your roof is covered with sheets of moss as in the picture above, then it needs to be pushed off the roof. This is usually done (with large amounts of moss) prior to killing the moss. The moss comes off in sheets and is generally not attached well to the roof. Sometimes I can just roll in up in carpet. Moss that grows in sheets attaches mostly to itself and not the roof. This means it can be removed without losing too many roof granules. It is important to get the bulk of the moss of the roof so that the water can flow off the roof. This is an urgent situation where it's important for water flow more than minor granule loss.

If you treated the huge sheets of moss, then when it rained (which it does often in Oregon) on the dead mass, it will form a huge soggy mess on the roof and hold excessive amounts of water on the roof. This would be a problem in and of itself. It could cause the roof to leak from water flowing sideways on the roof. So if you have hundreds of pounds of moss on the roof, I have found it best to remove the bulk of it before treating it. Then after the treated moss has died, the rest can be blown, brushed, hosed or weathered off as needed.