 In this video we will be looking at solving a common problem with leaking tiles due to moss buildup and broken tongs hiding underneath the tiles. The worst defender being the Marley modern or Redland stone wall type tiles. These tiles often come in two sizes as for instance with the Redland. The easiest way to avoid buying the wrong size is to just pop a tape measure across the width of the tile. The Redland stone wall would be around 340 millimeters whereas the mini stone wall would be around 300. Here's the main culprit of leaks moss in the joints. Because this style of plain flat interlocking tile doesn't have a raised joint with the adjoining tiles, unlike a lot of other designs it has to be said, the water cannot help but dribble into the joints where it hits the moss. This moss then blocks the watercourse and the water dribbles sideways and into the roof. Whilst jet washing the roof can prove effective, it tends not to clean the second water channel of the interlocking tile problem if at all. This reduces the margin of error and also doesn't show up any breaks to the waterproofing tongs hidden underneath and we'll see more of this later on in the video. If the property adjoins another, make sure you don't upset the neighbor by trampling all over their roof or cleaning their side without permission. On this project we'll be cleaning the mossy tile section closest to the camera. Previously out of pure coincidence, we have cleaned the roof of the property next door. Their neighbors in turn have, as you can see, been sold a new roof, no doubt after experience in the same problem with troublesome leaks. This is the section we'll be cleaning today however, approximately 50 meters square, very laborious but very effective. The first place to start is of course the top, but unless you want to take off the ridge tiles and re-bed them, it's easier just to give the roof a good scrape. As the top of the roof logically gets the leech rain water, there's little merit in removing the ridge tiles unless, of course, they're part of the job. As you can't physically knock up the first rub of tiles because they're fouled by the ridge tiles, be sure to thoroughly clean out the grooves with a pointy introw or similar. Take your time and when the top row of grooves are totally free of moss you can move on. To gain access to the tiles for removal, use the rubber grip of a hammer and firmly jab the tiles upwards. This will allow you to simply pick up the tiles below for cleaning. As you take off the tiles, you will probably see hot spots of damage, either to the tiles, the timber lath underneath or to the felt itself. Obviously change any broken tiles and repair any holes in the felt, especially if it's above a leak that shows itself inside the property. Damage to the timber lath itself often just comes down to a judgment core. If the timber is so rotten that the tiles cannot be placed sensibly back, this will need replacement. If however it just looks damp, this normally dries out under its own accord once the roof is fixed. Remember the roof covering is the waterproofing, not the felt underneath. Now for the tile cleaning itself, a pointy introw and a wire brush are very effective here. Scrape the face if necessary and the joints both male and female, then a quick wire brush to make sure. I find working with one tile permanently missing creates a gap and then popping them back as you go works really well. A word of warning though there is no easy way to do this. What you are effectively doing is re-roofing the entire roof with the existing tiles one at a time. As you go along you'll probably find breakages to the tongs that you didn't know were there because they were hidden by the covering tile. The two most common of these being the top break pictured here and the bottom break. These can bond with the moss to exaggerate the leaks even further. Once all the tiles are good it's time to pull down the tiles above. I've found the easiest way to pull the top row of tiles down onto your newly cleaned row is to use a flat pry bar and obviously this gives you plenty of leverage to adjust the final position should you find the gaps too large or too small. And here we are one third of the way down the roof. As you can see the top third is a lot cleaner now and some new tiles have been put into replace the breakages. If the roof is visible from the floor it's a good practice to use either reclaimed matching tiles if available or swap matching tiles from the gutter line at the bottom of the roof so that replacements aren't so visible from street level. As this roof though is not visible this has not been a concern in this case. Well here we are at the end of this project and here is the finished leak free roof. I hope this video has helped thanks for watching.