Top 5 slate roof problems in Melbourne

rusting and fading on a not very old slate roof — This rusting and fading slate roof is not very old.

If you’re the owner of a home in Melbourne with a slate roof, or even considering installing one on your new house, you may be interested in some of the most common problems we come across. The purpose of this post is to tell you about, and perhaps offer a solution, to the five most common problem inquiries we get from owners, or hear about. In our time in the industry, Abardeen roof slating has been involved in many and varied slate roof problems around Melbourne so we consider ourselves reasonably experienced in this area. And… yes, some stumped us for a while or were tricky and took us a couple of goes but we always solved them in the end.

Problem # 1 : Foot traffic on slate roofs.

This is probably one of ” the ” most common problems we see with slate roofs. It really doesn’t matter a great deal if your slates are one year old or one hundred years old. Most roof slates around Melbourne – note here I say most, not all – can handle our weather extremely well. However, the weight of an adult person is a different story. Over the years there can be many reasons why tradesmen need to go up on your roof. One of the most common reasons we encounter and the reason slate roof damage occurs is from TV antennae installers or repairers. They usually need to get to a high point or the chimney on your roof and in doing so can cause much damage to the slates. Other trades that we have seen up on slate roofs over the years are : solar hot water and pool heating guys – painters painting gables and walls above slates – bricklayers and renderers repairing chimneys – electricians running wires in hard to access ceiling cavities and even tree loppers using the roof as a platform to cut branches. It is true that some types of slates are more forgiving to foot traffic than others but even those can suffer significant damage when walked on often enough in the same area. Now I’m not saying that you keep all these tradesmen off the roof ; just ask them to exercise caution to eliminate or even minimize the damage that they do. Quite often these guys can access the roof from a point closer to where they need to go with a little effort. Some of them may not even have to walk on the slates at all if they give it a little more thought. Come across that one often – they are just being lazy. One thing that you do need to ensure is that before you allow anyone to go up on your roof is that they tell you if they do damage any of the slates. Many times we are called to repair slate roofs after rain when internal damage has already been done. The homeowners aren’t happy when they put two + two together and figure out the roof damage was caused by recent service trades and they weren’t told about it. Bare in mind that this also happens on tiled roofs as well but to a lesser extent. PROBLEM : Foot traffic damaging slate roofs and requiring repairs SOLUTION : Try to use service tradesmen experienced with slate roofs if possible and tell them to inform you if they do damage the slates.

Problem # 2 : Difficulty changing broken roof slates

Compared to metal or tile roofs another problem homeowners and other trades often comment about is the difficulty in changing a broken slate. With roofing tiles it’s a simple matter of lifting the surrounding tiles, removing the broken one and slipping the replacement into position – making sure the lugs are hooked over the batten. Similarly with iron roofs, unscrew the sheet , remove the sheet in question, slide in the new one and re screw. Roof slates are a different ball game. Because of their double lap system and being fixed into position with two hidden nails over half way up the slate they are difficult to remove without a special tool called a ” ripper “. If attempts are made to remove the broken one by somehow levering up the surrounding slates it usually results in many more being broken and it can just snowball into a large area of broken slates. However, with the assistance of a ripper and a bit of experience using one, broken slates can be changed relatively easily – albeit with a bit more difficulty than tiles. You need to bare in mind here that this fixing method makes slates very superior to tiles in resisting coming loose or blowing off during storms and high winds. PROBLEM : Difficult to change broken roof slates SOLUTION : Need to use a ripper.

Problem # 3 : Most slate roofs have a steep pitch.

This is true…. but only just. Most slate roofs can be – but not always – more steeply pitched than tiled or metal roofs. I really don’t know why this is considered a problem by homeowners. The most common average type pitch of Melbourne’s period homes is around 30 degrees. When tiled roofs began to dominate the housing scene around the 1930’s they were also around the 30 degree mark. Over the following decades the average pitch of tiled roofs slowly decreased to where it is today – around 22 degrees. Slate roofs during this time almost disappeared completely and when they re-emerged in the 70’s, surprisingly enough, they were commonly installed on pitches around the 20 degree mark, sometimes lower. This lowish pitch had a lot to do with the look of the home the owners and builders were trying to achieve. Bottom line here seems to be people associate slate roofs as being steep and therefore problematic and unfriendly for maintenance and other services. Truth is tiled roofs can be as steep as slate. With the correct equipment, repairs to steeply pitched slate roofs is a simple matter – certainly no more difficult than a steep pitch tiled roof. It’s amazing how many people over the years have commented that they’re not sure about a slated roof because of the steep pitch they require. When viewed from the front of the house you want a bit of pitch so as to see the roof – the right roof covering can after all create a beautiful feature to the home. To me, slate roofs with a pitch of say 28 – 30 degrees look great as you can really see more of the face of the slates and their beautiful natural appearance. Compare that to a tiled roof at around their common 22 – 23 degrees and all you really see is the small edge of their tails – not nearly as nice as slate at around 30. PROBLEM : Not a problem really but – most slate roofs have a steep pitch. SOLUTION : No solution needed – the steep pitch highlights their beauty – repairs and services are easy, just the right equipment needed.

Problem # 4 : Young slate roofs rusting and fading.

Here’s a problem we come across and have homeowners ask questions about. There are quite a few slate roofs around Melbourne – some not that old either – that are not weathering too good. These roofs could have been installed any time from the 70’s up to as little as 12 months ago. All still young in my opinion. In most instances we are called to repair a leak and invariably the homeowners ask why the roof is staining and seems to be progressively getting worse, or why there are many of the slates fading to different degrees. The staining is pyrites rusting – or iron particles if you like – in the slate. The fading is due to Calcium Carbonate in the slate. They are usually surprised when they learn that both problems are going to worsen as time goes on and there isn’t much that can be done to stop it. The rusting in many cases can eventually puts holes through the slate and cause flaking and breaking. The fading slates may eventually be really soft and go powdery. The speed at which these roofs rust and/or fade depends on the type of slate. I can’t even answer that myself as really only time will tell. Some roofs tend to rust and/or fade slower than others but from what I’ve observed in my time in the industry they always eventually need replacing. It might be after 10 years or 30 years – both not nearly long enough for a good slate roof. It’s interesting to note that most of these homeowners had no idea that there are different quality roof slates. PROBLEM : Slate roofs that are not very old rusting and fading. SOLUTION : Do your research before choosing the slate for your home and for a trouble free roof only choose a quality slate.

Problem # 5 : Moss and lichens on slate roofs.

Here’s an old favorite of mine – the mossy slate roof. We get lots of inquiries about how to get rid of moss from slate roofs. We also get a fair few inquiries from people looking for re-claimed slates with moss on them for an extension to match their original roof. Homeowners either love it or want to get rid of it. Well, this is after all a post about slate roof problems so i’m assuming you want to remove it. There is a couple of ways to remove moss and lichens from your roof – none permanent. If you don’t ever want it on your roof you’re going to have to keep removing it every so often. Here’s the main ways

Hand scraping with, say, a paint scraper or similar :- Very labor intensive, can’t get it really clean, still leaves lots of spores on the slates, regrows fairly quickly.
Water pressure cleaning : – Removes it reasonably well, need to be careful not to damage or dislodge the slates on older roofs, regrows after a while.
Commercial moss remover : – Sprayed onto the moss, let it weather off naturally or hose it after the moss has died, cleans reasonably well, regrows after a while.

It’s very difficult to keep moss off slate roofs, or even tiled roofs for that matter. If you really want it off – and kept off – it will be a continual battle. Remember it’s thickest on the South sides and probably almost non existent on North facing sides. PROBLEM : Removing moss and lichens from slate roofs. SOLUTION : Learn to like it or choose one of the above methods and be prepared to keep at it every once in a while.