Ah, is there anything nicer than a clean and clear roof? There is little better than a roof that is shiny and clean. And, when the roof in question has some miles on the block, isn’t it amazing how it looks like new? Then you look at your old cruddy roof, and it really doesn’t look all that great.

You get a brainwave – what if you get your roof power washed? You could have it looking all fine and dandy again in next to no time flat. You could have your own new roof. But, before you haul out the power-washer, think carefully.


Do You Have Asphalt Shingles?

If the answer is yes, then power washing your roof is going to make it look as good as new. In fact, you may even get far better results than you expected because you will need to replace your roof sooner than you expected as well.  

And, since the roof needs replacing because of a maintenance issue, you’ll have to pay every cent for that shiny new roof.

And no, I am not being overly dramatic here. To understand what could go wrong, let’s have a look at how asphalt shingles are made.


How They Are Made

The shingle itself keeps some water off your house by redirecting it, but it must be waterproofed to ensure that the wood/ pulp mixture does not absorb water. A layer of asphalt is sprayed over the core to ensure that it is waterproofed.

So, the waterproofing effect is actually from the asphalt and not the core material.


How They Degrade

The asphalt is bonded to the core and adheres pretty strongly. If it was inside and not exposed to weather conditions, it would probably remain strong for hundreds of years. But it is out in the sun, rain, wind, hail, etc. all year round.

Over time the bond weakens, and the asphalt starts to trickle off. Eventually, when most of the asphalt is gone, you need to replace the shingle because there is nothing that is protecting it from absorbing water.


Why Power Washing Your Asphalt Roof is a Knucklehead Move

I am pretty sure that you can see where we are heading with this. If rain can chip away at the bond between the asphalt and the core material, rain plus pressure is going to do a spectacular job of degrading that bond fast.

Your roof will look clean but will have been weakened. You have literally just power washed years off the useful lifespan of your roof.



Don’t be a numbskull, a little bit of moss is not going to do all that much damage. if the state of your roof is really getting on your nerves, get up there with a soft broom and sweep away as much debris as possible.

Our best advice, though? If the “dirt” on the roof is bothering you, don’t look at it. There are so many other things that you can do at ground level to create your perfect space – why go and look for trouble when there is none? If you need a free estimate on a roof though, make sure to contact Prominent Construction.  

Related: Not sure if you can replace your roof during the winter?

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