Frequently Asked Questions
Below you can find answers to our most frequently asked questions about roof moss removal and products designed to inhibit early re-growth
You can find further information on our roof moss removal page
What is the best chemical to treat the moss/roof?
Dont go for garden centre type chemicals, these are typically designed
for use on grass and generally very weak. Painters merchants will sell mould/algae chemicals designed to kill off organic growth to damp walls prior to painting - try these
type of chemicals but check they are suitable for external use. Here is a list of moss treatment products.
Can I treat the roof moss with a moss killer without removing it?
The problem here is the simple fact that all that moss will still be up there - gradually being washed down into the gutters causing regular blockages. You would also have to use significantly more moss killer.
Is it safe to pressure wash a roof?
You can do this if you wish however if you have older clay or concrete tiles this process may strip the colour from your roof tiles. It may invalidate any warranty given by the tile manufacturer and there is also the flood risk. It is also a very messy way to remove the roof moss. Shingles should never be pressure washed - damage is likely.
What type of company will carry out this type of work?
General roofing companies are the best choice, unlike a roof coating company they will have more experience in carrying out any repairs to the roof. The usual checks should be made: Do they have public liabilty insurance? Can they supply addresses of previous customers? Are they a member of a recognized organization? Did they send a salesman to inspect the roof or a tradesman?
Are roof coatings and sealants really bad?
Not really, they are just being mis-sold by some companies and as a new product there is some doubt as to how long the coating will actually last and what the cost of a
re-coat would be. They do have advantages such as preventing moisture to soak into the tile, but almost all concrete tiles are designed to handle this without any coatings
or sealants.
What are white/yellow marks on my roof?
Litchens - they are a type of algae/mould organism. A good moss killer will kill them off but dont expect them to dissapear overnight.