First, we have to be honest that when it comes to the roof of a home, it’s hard to create a totally natural and fully waterproof canopy without some kind of vapour barrier. The roof is the most important part of a house. I’d argue it’s more important than foundations. Case in point: my barn has no foundations to speak of and it’s been standing 200 years. But as any local here will tell you, if the roof on the barn goes, the barn has no more than a few years left before it collapses.
Upshot: If the roof is secure and functioning properly as a rain shelter, you’re good. If not...agh. So, many times it's going to be hard to get away with making a watertight roof without a vapour barrer.
What did they do in times of old then?
Well before the modern age and vapour barriers, people still made weather-resistant roofs. But...here’s the painful truth of the matter, they often needed quite a lot of maintenance and repair. Residents were also used to sporadic leaking, and roofs had to be retiled, re-thatched, or re-mortared from time to time. That was just how it was. Not that modern roofs are maintenance-free either of course, but there is one crucial difference: most people in olden days weren’t building alone. They worked as communities. Re-tiling a roof is pretty easy when there’s a crowd of you, but doing it single-handed, or even as a couple, is a lot slower and more tedious.
Anyway, here are your six beautiful natural roofing options, plus whether or not you can get away without a vapour barrier.
1. Living Roof
In my opinion the sturdiest of the lot. I love a living roof. I have two articles on making living roofs. Here’s how I made mine and here’s how Cath Coffee in London made hers.
Pros: If made properly they don’t leak, can’t crack, animals can wander all over them without breaking them, they’re hurricane proof, soundproof, and possibly help retard a fire too. Basically no maintenance required once it’s built.
Cons: These are heavy, so you need a decent roof structure to support the weight, which could end up being the equivalent of a couple of elephants (albeit spread more thinly). You’ll need some plastic, which is of course the devil these days. Also, a living roof really needs a damp climate to actually be ‘living’.
Vapour barrier? Definitely. You’ll need two in fact, to be sure of success. Something like an EPDM or bitumen will go over the roofing boards, then you’ll need a couple of sheets of plastic as a root barrier.
Tiles are of course some of the oldest and most widely used natural roofing options in the world. For centuries at least, people have been firing clay and turning it into pots, amphoras, and roofing tiles. I confess tiles aren’t my favourite because they’re so frickin’ fragile, though on the plus side, they can look beautiful, and you might also get away without a vapour barrier with them. But tiling is definitely a two-person job unless you want to get rather tired.
Pros: You can use them to catch rainwater (big plus), beauty, simplicity. Possibly no need for a vapour barrier.
Cons: Fragile, can’t handle much falling on them without cracking, prone to get ripped off in gales, repairing tile roofs is annoying.
Vapour barrier? This really depends on which tiles you’re using, and how desperate you are to stay perfectly dry. For the more modern, interlocking roof tiles, if it’s an exterior roof, say a porch or a shed or something, you can easily get away with no barrier. But for a house, and for the old school Mediterranean curved tiles, a breathable roofing membrane under the tiles is usually recommended.
If you live anywhere with slate (such as Galicia, Spain) slate slabs make amazing roof tiles. They’re more forgiving to lay, and a bit less likely to get ripped off in the wind than traditional terracotta tiles, because they’re flat.
Pros: Sleek, easier to lay than terracotta (in my opinion). Good for rain harvesting.
Cons: You really need to be in a slate area to make a slate roof feasible and sustainable. Like other tiles they are potentially a bit leaky. And you have the issue of repair when the slate slabs crack (because a tree branch fell on them or something). Slate tiles are also fairly heavy.
Vapour barrier? See my comments on terracotta tiles above.
Oh, who wouldn’t want a thatch roof? Romantic, completely natural, and super snug too. Thatch roofs are usually made from reeds, but people do also use grasses (though grass will last far less time). If thatch is made professionally it is nice and weatherproof too. So what do you need to consider?
Pros: Insulating as heck. And of course thatch is so beautiful.
Cons: Fire risk. Thatch needs decent maintenance.
Vapour barrier? Ah well, according to the experts this all depends on if it’s a cold or a warm thatch roof. Here’s a good article explaining when and when not to use a vapour barrier with thatch.
5. Madras Roof (Brick and Lime Mortar)
One of India’s traditional roofing techniques is a method called the Madras roof. Bricks are laid at a 45-degree angle over the rafters and mortared using a special lime application. Karen Shetty explained how that was done here.
Pros: Beautiful, inexpensive, perfectly natural, honouring tradition.
Cons: Fairly heavy, so decent supporting rafters are required. Like thatch, if you are dead-set on an optimum job, get a professional to lay this kind of roof.
Vapour barrier? Normally vapour barriers are not used in India with these roofs.
6. Bamboo Roof
Ooh if I lived in a climate with bamboo… Bamboo is nice and sustainable, doesn’t weigh too much, and is a material geared to creating gorgeous roofing structures. There are two ways to use bamboo in roofing. Usually you see the bamboo used for the frame and then some sort of thatch/reed roof over the top. But you can also use bamboo cut in half to form a kind of crenellated roof which would be excellent for rain harvesting.
How to make a simple bamboo roof:
Pros: Inexpensive (if you are in the bamboo zone), sustainable, lightweight, cool.
Cons: Bamboo can go mouldy if not treated properly.
Vapour barrier? Because bamboo roofs are usually found in warm humid climates, and because bamboo is pretty efficient at channeling away water, I’d say it would be a bad idea to stick a vapour barrier underneath due to the risk of mold.
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