Treating moss on a pitched roof

Roof 230X230


When moss starts to grow on a roof it can be unsightly as well as becoming a nuisance and, if left untreated, moss can cause damage to a roof. So, when owners have had enough of blocked guttering, sweeping driveways or patios of fallen moss or the very expensive job of replacing broken roof tiles it is time to rid the area of moss growth. But what is the best way of removing moss or of killing moss? Being totally honest, there isn’t one method that will suit everyone. Most roofs are different to each other, most owner’s requirements are different, access to roofs is vastly different and the moss cleaning budget will also vary. But there is one thing that most people can agree on and that is that they want to kill the moss and remove the moss in the most efficient and cost-effective way.

In our opinion, it is always better to try and remove as much of the moss or lichen growth as possible BEFORE using any moss killing chemicals or moss prevention chemicals. This can be done by brushing the roof, lightly scraping the area or even by using a small pressure washer. Now before some of you gasp in disbelief at the thought of having to squeeze into a Spiderman costume, scale a wall and skip, nimbly, across a slippery, moss infested pitched roof, let me explain myself. Firstly, removing moss or lichen before the application of a moss killer will save you money and time. If access to your roof is possible then any moss that you can remove will mean that less moss killing chemical will be required and, with the moss removed, the moss killer will be able to be in contact with the surface. If using our BATICLEAN CR then this is designed to kill both moss, lichen and their spores. With the moss removed the BATICLEAN CR can be in contact with the surface therefore kill any spores that are present. Also, the more moss growth that you can remove then the better the chance that you will be able to complete the moss killing job with just one application. The thicker the moss growth then the higher chance that you may have to make more than one application. Secondly, you should only attempt to reach areas that are safe to reach. If you can only reach areas of your roof from a window, Velux or from a ladder then that is fine. Anything that you can remove is better than removing nothing at all. However, if you can’t remove anything prior to an application then don’t worry, if you follow the application instructions for the moss killing product then your cleaning will be just as successful. It may just take a little longer.

I have mentioned various ways of removing the moss growth from your roof and I know that some of you will have heard various scare stories about what you should and shouldn’t use on different types of roof covering. Let me start by saying that you shouldn’t use anything that is going to damage your roof surface nor use anything that you are going to struggle to use. Brushing is very unlikely to cause any damage however, if you have sand covered tiles, then you could dislodge some of it. Likewise, scraping is also unlikely to damage tiles. The big issue comes with a pressure washer or a hosepipe. Again, using one of these responsibly, will not cause damage to your roof covering. Always spray down, towards the guttering, and not up. This way the water will not be driven under the tiles. Also, just because you are using a pressure washer it doesn’t mean that you are going to have so much pressure that you are going to blast half of your roof into the neighbours’ garden. Providing that you use the water pressure sensibly then you will not cause any damage.

Once the area is clean and dry then apply CONCENTRATED MOSS & ALGAE KILLER - BATICLEAN CR. This will kill any remaining growth and spores and is designed to stay on the surface to inhibit re-growth. This means that there is no rinsing required. The surface can then be left, and a new coat applied every 12-36 months or when the first signs of fresh growth appear. BATICLEAN CR is also the best option when you are unable to remove growth or would be unable to rinse the surface.

If the roof has lichen coverage (that can be very difficult to remove without killing it first) the whole area can be treated with BATIFACE (or just spot treated), after application it should be left for 15-30 minutes before being rinsed. It is far better to rinse the BATIFACE from the surface before it has had chance to dry. It is for this reason that we suggest rinsing a short time after application. Rinsing can be done with a pressure washer, hosepipe or just by pouring water across the treated area. You may also find that brushing the area, whilst rinsing, will help to remove the most stubborn areas of dead moss or lichen growth. Once the area is clean and dry then we recommend the application of BATICLEAN CR to ensure that the whole area is free from moss spores.

For additional long-term prevention of re-growth the area can be coated with ROOF & WALL SEALER - Hydrosil BS which will prevent re-growth, water ingress weather damage, dirt etc. for up to 10-years. Once the roof is clean & dry (after the initial clean), it should be sprayed with BATICLEAN CR, to ensure the roof is completely treated prior to applying the HYDROSIL BS.