Roof moss is unsightly, blocks both gutters/pipes and also leaves black marks on patio slabs and conservatory roof panels. It will gradually encroach over the entire roof and many homeowners prefer to have it removed. Once the moss is taken off, the old roof tiles will look much brighter and cleaner, even if no chemicals or pressure washers are used during the process.
Here you can find a list of moss killers, they are chemicals that are diluted with water and then applied to the roof (or patio) preventing regrowth. It is best to apply these after the moss has first been removed, if you spray the roof without first taking the moss off, the rain will wash all the dead moss into the gutters causing them to block up.
Will Moss Damage My Roof Tiles?
This is a good question and one I often hear, the answer is maybe but for most roof tiles it is most certainly unlikely. Although getting rid of the moss on your roof does has many other benefits. Most of my customers want the moss removed to either improve the appearance of the roof or because they are fed up with the blocked gutters and clumps of moss falling to the ground and sticking to the patio, car, conservatory roof etc.
Have you ever seen the “feet” that you place underneath plant pots in your garden? The purpose of those feet is to allow water in the pot to drain away, without them the pot will remain wet/damp and when the temperature drops below freezing in winter the pot will crack. Water has that effect on terracotta, clay and even concrete, especially thin concrete such as roof tiles.
Moss holds water, so by removing the moss from the roof you are reducing the possibility of tiles suffering from winter cracks. Moss also tends to grow on cement, so it can disturb the bond between ridge/apex tiles and the roof.
By itself moss wont damage the tiles and the biggest advantage of a moss removal project would be on the guttering. With less blockages they can work more efficiently and require much less maintenance. The chances of an expensive blockage in the underground drain are reduced and products such as gutter guards and down pipe filters will not clog up so quickly.
So is it Worth Removing Roof Moss? Is it Cost Effective?
If you have excess roof moss and you are concerned about the tiles never having the opportunity to dry out, then yes removing the moss and preventing regrowth with chemical moss killers is worth considering. If the growth is only mild then it may not be needed. It depends on whether you are fed up with constantly having to clear out the gutters or seeing clumps of moss on your lawn/patio etc.
Having the moss removed from the roof will improve the kerb appeal of the property but won’t increase it’s value. Excessive moss might be something that is highlighted on a survey as a potential issue but normal levels of growth shouldn’t cause any problems.
Moss on Clay Tiles
I never recommend climbing over a roof with clay tiles as they are so fragile and are more likely to break. So if you have these tiles on your roof your options are very limited. The best option is to use a long reach pole with either a scraper or wire brush attached to the end and try to remove as much moss as possible without actually walking onto the tiles.
This work could be dangerous if done from a ladder but an access tower raised to gutter height would be perfect.
A chemical can then be sprayed onto the roof to kill off any bits that were missed and to prevent early regrowth. I have completed several projects like this and in my opinion it’s a safer option.
Concrete tiles are completely different, you can walk or rest a roof ladder on these and they rarely break.