Tile Roof Question for any NCKA Roofers

I recently had an issue with my 20+ year old concrete tile roof.  Apparently, when the house was built the roofer didn't run the felt all the way to the edge of the roof and water got under the felt and caused a small amount of dry rot to occur.  I had a roofer come out and remove the tiles on that portion of the roof and replace the rotted wood and put new felt down all the way to the edge.  The roofer informed me that the valleys in my roof were clogged with algae and mud and water was going to be channeled under the tiles which would destroy the felt and eventually the wood decking too.  I decided to have him remove the tiles along the valleys and clean all of the muck out and replace the tiles.  The amount of muddy stuff clogging the valleys was amazing!   The roofer said a roof like mine should be cleaned at least every 5 years.  He indicated that the large amount of trees around my house and the lack of direct sun on the front of the house is a contributing factor.  So here's the question:  Do the chemical wash products that claim to solve this problem work and if so are they the best solution?  Does it make sense to pay a roofer a few hundred dollars to remove and replace the tiles along the valleys and clean them every few years?

Thanks,
Martin

I will ask my brother today and direct him to your post if he doesn't see it first...

If it only a few hundreds a year I would let the "professionals" do it.  The benefits outweigh the risks of breaking you neck, cost of the chemical, and most of all fishing time 

If it only a few hundreds a year I would let the "professionals" do it.  The benefits outweigh the risks of breaking you neck, cost of the chemical, and most of all fishing time 

x1000

Good advice from Tote and Sonny.  I hate ladders anyway.  Thanks guys!

Good advice from Tote and Sonny.  I hate ladders anyway.  Thanks guys!

We're looking out for our LS brothers 

Good advice from Tote and Sonny.  I hate ladders anyway.  Thanks guys!

Don't risk your neck. Let Sonny do it in exchange for kayak storage in your garage.   

Concrete roof tiles are terrible!! Depending on how large/how many stories and how many seams you have its not a hard job to do. Then again my experience is with my small 1 story house that only has 3 seams to do! In the end it is much easier to have a pro do it though. Where are you located? I had a really good experience with a guy up here in the north bay if you would like a reference.