Cheap roof ideas?

What are some cheap/free roofing materials we could look at getting? We're fixing to start building an earthbag house and we'll have about 1420 sq ft of space to cover. Thanks! Also we live in Alabama.

Split your own shakes with a froe. That's a good, free, roof. All you need is tools, fasteners, and lots and lots and lots of skilled labor. (But after the first ten or twenty hours, i bet you'll be pretty skilled yourself.) These are a fire hazard.

Fire some clay tiles. Same as above: free, but takes numerous hours. Plus, they're heavy, and your roof needs to be stronger than average to hold them.

Roll roofing. This isn't free, but it's much cheaper than shingles. It goes on quick and easy. It lasts ten years of you're lucky. It's made out of petroleum. It looks cheap.

Roofing is a tough question.

Mike Cantrell wrote:Split your own shakes with a froe. That's a good, free, roof. All you need is tools, fasteners, and lots and lots and lots of skilled labor. (But after the first ten or twenty hours, i bet you'll be pretty skilled yourself.) These are a fire hazard.

Fire some clay tiles. Same as above- free, but takes numerous hours. Plus, they're heavy, and your roof needs to be stronger than average to hold them.

Roll roofing. This isn't free, but it's much cheaper than shingles. It goes on quick and easy. It lasts ten years of you're lucky. It's made out of petroleum. It looks cheap.

Roofing is a tough question.

Roll roofing sounds interesting. Any special kind? Like a roll of flashing perhaps? We thought about cleaning off and using the aluminum siding from a mobile home we can tear down but didn't know if that would be safe enough. The siding is really old and filthy. Could we clean, disinfect and maybe treat it with something and make it safe?

Or bamboo maybe? A neighbor of ours has free bamboo trees she's trying to get rid of but we don't know what all it would entail to use those as a roof. We have access to a lot of pallets as well and thought about using those for our roofs but are they safe enough? Perhaps if we treated/stained them somehow?

Or a ferrocement roof perhaps?

Roll roofing sounds interesting. Any special kind?

I meant like this, for example.

Like a roll of flashing perhaps?

There are a couple of types of metal roofing, and one style is lapped metal shingles (either aluminum or steel). Metal roofs are great, but they definitely aren't cheap.
Doing the math very roughly for what it would cost to build a makeshift roof out of aluminum flashing, here's what I come up with.

Assuming a 6/12 pitch, you'll have (1420*1.118=1587.56, round up to 1600 to include eaves) sq ft of roof surface.
Flashing: 8.33 sq ft for $10.47, or $1.26 per sq ft.
I'd lap the flashing rows approximately 50%, or 5", so you'll need 3,200 sq ft of material.
That's $4,032 of flashing.

I could probably stop there. This isn't a cheap approach.

But there's a little more. Remember that you shouldn't use steel nails on aluminum because of galvanic corrosion; you need aluminum nails, which cost more. Nailing down little strips also takes lots more nails.
(Two slopes, each 20'x40' means 48 5" courses each. Each course gets, say, a nail every 6" over its 40' length, that's 7,680 nails. At $5.76 per 414 nails, that's another $106.)
Aaaaand... probably another couple hundred for underlayment.

We thought about cleaning off and using the aluminum siding from a mobile home we can tear down but didn't know if that would be safe enough. The siding is really old and filthy. Could we clean, disinfect and maybe treat it with something and make it safe?

The way aluminum siding is bent, it's designed to shed most of the water off, vertically. Some water is allowed to get behind it, and if you look at the bottom edge, you'll see it even has weep holes to let that water back out again. I can't picture an easy way to reuse it on a roof. Maybe if you somehow chopped it into pieces and used them as aluminum shingles?

Or bamboo maybe?

Is it one of the huge species? Like 6" diameter? Maybe you could cut barrel tiles out of them?

Or a ferrocement roof perhaps?

This, I think, has been done.
Has it been done in a fairly wet place like Alabama? I don't know.
Would I live under one myself? Maybe if it were built by someone who had done five or ten other structures first.

Felicia Daniels wrote:What are some cheap/free roofing materials we could look at getting? We're fixing to start building an earthbag house and we'll have about 1420 sq ft of space to cover. Thanks! Also we live in Alabama.

The question brings to mind the addage "Fast, cheap and good - pick two". If cheap is #1, you'll need to make a decision on #2.

For "good", what comes to mind is a diy green roof with self-harvested round wood timber framing. Your earthbag structure should be pretty strong and though your location wont need an exceptionally thick roofing for this to work, that soil mass is going to be pretty heavy, especially when wet. Membrane can be as easy as a double layer of 6mil black plastic over salvaged carpeting and/or billboard tarps. It will take seemingly FOREVER to put together, though, and lots of hours moving soil (much like the earthbag construction technique itself).

For "fast", roll roofing definitely fits the bill... it wont last long, will look pretty awful and your rainwater runoff will probably be pretty gross with chemicals, but it's cheap and fast. The framing for this could probably be made with cheapo 2x2s in your climate since there's no snow load to worry about

Mike Cantrell wrote:

Roll roofing sounds interesting. Any special kind?

I meant like this, for example.

Like a roll of flashing perhaps?

There are a couple of types of metal roofing, and one style is lapped metal shingles (either aluminum or steel). Metal roofs are great, but they definitely aren't cheap.
Doing the math very roughly for what it would cost to build a makeshift roof out of aluminum flashing, here's what I come up with.

Assuming a 6/12 pitch, you'll have (1420*1.118=1587.56, round up to 1600 to include eaves) sq ft of roof surface.
Flashing: 8.33 sq ft for $10.47, or $1.26 per sq ft.
I'd lap the flashing rows approximately 50%, or 5", so you'll need 3,200 sq ft of material.
That's $4,032 of flashing.

I could probably stop there. This isn't a cheap approach.

But there's a little more. Remember that you shouldn't use steel nails on aluminum because of galvanic corrosion; you need aluminum nails, which cost more. Nailing down little strips also takes lots more nails.
(Two slopes, each 20'x40' means 48 5" courses each. Each course gets, say, a nail every 6" over its 40' length, that's 7,680 nails. At $5.76 per 414 nails, that's another $106.)
Aaaaand... probably another couple hundred for underlayment.

We thought about cleaning off and using the aluminum siding from a mobile home we can tear down but didn't know if that would be safe enough. The siding is really old and filthy. Could we clean, disinfect and maybe treat it with something and make it safe?

The way aluminum siding is bent, it's designed to shed most of the water off, vertically. Some water is allowed to get behind it, and if you look at the bottom edge, you'll see it even has weep holes to let that water back out again. I can't picture an easy way to reuse it on a roof. Maybe if you somehow chopped it into pieces and used them as aluminum shingles?

Or bamboo maybe?

Is it one of the huge species? Like 6" diameter? Maybe you could cut barrel tiles out of them?

Or a ferrocement roof perhaps?

This, I think, has been done.
Has it been done in a fairly wet place like Alabama? I don't know.
Would I live under one myself? Maybe if it were built by someone who had done five or ten other structures first.

Thanks for all your help! Roll roofing might end up being what we have to go with. And it's safe to use for all our water needs including drinking? Here are a couple more ideas we had.

A tarp system. Either creating a funnel out of it to drain straight into the barrels (like in the first picture) or attaching it to trees/posts and angling it (second picture)

Or getting corrugated black pipes (pic 3) and either creating a funnel out of them (like how we would with a tarp) or attaching them over our pallet roof to use as the roofing material. Do you think these would work and be safe/worth it?

Felicia Daniels wrote:
Thanks for all your help! Roll roofing might end up being what we have to go with. And it's safe to use for all our water needs including drinking?

No way I would drink water that I harvested from a roof covered in rolled roofing.

Thank y'all! We'd like it to be cheap and good for our 1 & 2. I just looked at my design again and realized that I was going about the square footage wrong. We do need about 1420 total but only 500 to catch our water. The rest of the roofs could be anything as long as it isn't gonna look awful and will be durable. And hopefully as recycled as possible. So for the rain roof we had thought about a green roof but we were worried about the water having to go through the soil and all before reaching the downspout and going into the barrels. Is that safe or would we have to modify the green roof some to make it safe? And given that we only have about 500 of rain roof to do now, what would be the cheapest best option for our ebag house? Like I said we will be applying cob and then covering it with a lome plaster or linseed oil. Which would be better?

At one time I had an idea of making slumped wine bottles into spanish type roof tiles for clean water catchment, I was thinking of it for like a sun porch or a diffused light greenhouse type structure. I wrote this a few years ago
http://askwildehilde.blogspot.com/2013/03/green-greenhouse-what-concept.html
It's an art project, and would take some brain work to design the slump mold to suit and to design the frame to hang the bottles; from perhaps an already available commercial mold out there..there are lots of great slumping sites..

Thanks girl! I'll look into that but it might be too time consuming for us😕

Felicia Daniels wrote:Thank y'all! We'd like it to be cheap and good for our 1 & 2. I just looked at my design again and realized that I was going about the square footage wrong. We do need about 1420 total but only 500 to catch our water. The rest of the roofs could be anything as long as it isn't gonna look awful and will be durable. And hopefully as recycled as possible. So for the rain roof we had thought about a green roof but we were worried about the water having to go through the soil and all before reaching the downspout and going into the barrels. Is that safe or would we have to modify the green roof some to make it safe? And given that we only have about 500 of rain roof to do now, what would be the cheapest best option for our ebag house? Like I said we will be applying cob and then covering it with a lome plaster or linseed oil. Which would be better?

Collected water from the green roof will have a higher TDS (total dissolved solids - mostly organic material and clay particles from the soil) and more potential for contamination from poop (birds) that doesn't wash out quickly enough for a first flush diverter. I wouldn't drink it without really good filtering with maybe some UV or boiling treatment, just to be on the safe side, but that would work fine for utility water (washing and dishes, irrigation, etc) with minimal filtering. That's our plan for when we build our cabin (cordwood/cobwood infill, roundwood timber frame, thick green roof). We're currently using tarp collected rainwater for drinking already and will probably be setting up a permanent type structure with metal (or something) for drinking water on top of the green roof, plumbed separately and fenced/caged well to keep the ducks from contaminating it. If a section of the roofing will be elevated more than the other portions, you could easily use a different material more suitable for drinking water collection on just that section and plumb it separately. If not, you could do like us and build a smaller section of roof on top of your roof for that. 500 sq ft is pretty small in the grand scheme so should be doable

Thank you!

I built two cabins while living in Georgia sheathed on the outside with carpet stuccoed with cement. The roof was framed with bamboo or pine poles, then a deck of two layers of overlapping cardboard, then overlapping large pieces of plastic....easy to scrounge from mattress and furniture stores. Then overlapping courses of carpets....preferably the short or short looped nap rather than something shaggy. Near any town this should be easy to find, from dumpsters, Craigslist, etc. If it's new carpet let it age out in the weather for a while, as it's often treated with a water repellent. Begin the stucco by splashing soapy water onto the carpet....we used old greywater. The soap will help the stucco wick down into the carpet. Then mix portland cement up with a bit of sand rather soupy and slather it on with rubber gloves. You can mix paint into it for color. The cement binds to the carpet and it hardens into a solid sheet. I had five people on that roof at one time, and in ten years it had not leaked anywhere. Eventually, moss grew on it, so I think it could be used as a base for a living roof, possibly without the stucco at all. The plastic layers shed water anyway, and the carpet protects the plastic, and the stucco prevents the sunlight from slowly breaking down the carpet. I did the walls the same way, although on the cabin with a good roof overhang I used a mud stucco (actually more sand than clay, higher clay encourages cracking) and just applied a thin wash of portland and paint water on with a brush as the final coat. Cement can often be had for cheap at a store like Home Depot if you see a pallet of broken bags somewhere...

Do you have access to any birch trees? If so, you might want to consider a traditional Finnish birch bark roof. Birch bark is the underlayment. Wood poles are the shingles. I don't see any reason why you could not use bamboo for the wood poles since you already have a supply of that.

Thanks you guys! What about this idea? Doing a dome with no roof, with lime plaster covering the outside (cob strictly on the inside) and attaching a gutter around the roof (like a headwrap I guess lol) and the rain will roll down the dome roof into the gutters and into the barrels? Is that safe or would that work?

Very similar to Mr Burns carpet/cement/paint roof above is the latex concrete roof. I often imagined building a cylindrical earthbag structure and topping it with a reciprocal roof covered in latex concrete. I've only built a tiny shed roof and sealed odd-shaped holes in other buildings with the method. So far they're holding up great. The idea is using a reinforcing mesh (like fiberglass flyscreen, burlap or carpet) and impregnating it with a cement/latex or acrylic slurry and adding successive layers or the same slurry mixed with sand. You can google various projects. There is an excellent book written by leaders of a project to roof third world housing with this method. And these folks seem to break it down pretty well:

http://velacreations.com/howto/latex-concrete-roof/

That's an interesting idea thank you!!

How cheap does it need to be?

When I put a roof over my WVO processing/storage stuff, I used galvanized steel sheets; not the wavey sort of corrogated, this grade: https://www.homedepot.ca/en/home/p.tough-rib-galvanized-12-ft.1000116723.html

It was a heck of a lot easier than some of the more esoteric options, and it's prime water-collection material. Plus, if I don't need this shed down the line, I can take it apart and reuse the bits, or someone else can.

It was less than a dollar per square foot, retail, in Canada. I assume in the states one could do better on pricing, and better again if you can find someone with a contractors discount to use. Yes, you need gasketed fasteners, but still... Less than the improvised flashing example, and while I think it's more for the material than for an EPDM type roll roof, it doesn't appear to be much more, and you need less support as you aren't piling heaving earth atop it. In my case purlins were plenty to support it, major time/weight/$ savings vs something needing plywood or planks below it.


As far as linseed oil vs lime plaster, lime plaster is heavy duty, with time you're basically turning the top layer of the wall to stone... But lime is not real fun to work with. So, whether or not you need it would be dependent on climate, and overhangs, and whether you've got a nice tall foundation or are cladding the lower portion of the walls in something... and of course on how you feel about doing it the hard way now to hopefully lower maintenance later on...

Don't skimp on the overhangs!

Dillon Nichols wrote:How cheap does it need to be?

When I put a roof over my WVO processing/storage stuff, I used galvanized steel sheets; not the wavey sort of corrogated, this grade: https://www.homedepot.ca/en/home/p.tough-rib-galvanized-12-ft.1000116723.html

It was a heck of a lot easier than some of the more esoteric options, and it's prime water-collection material. Plus, if I don't need this shed down the line, I can take it apart and reuse the bits, or someone else can.

It was less than a dollar per square foot, retail, in Canada. I assume in the states one could do better on pricing, and better again if you can find someone with a contractors discount to use. Yes, you need gasketed fasteners, but still... Less than the improvised flashing example, and while I think it's more for the material than for an EPDM type roll roof, it doesn't appear to be much more, and you need less support as you aren't piling heaving earth atop it. In my case purlins were plenty to support it, major time/weight/$ savings vs something needing plywood or planks below it.


As far as linseed oil vs lime plaster, lime plaster is heavy duty, with time you're basically turning the top layer of the wall to stone... But lime is not real fun to work with. So, whether or not you need it would be dependent on climate, and overhangs, and whether you've got a nice tall foundation or are cladding the lower portion of the walls in something... and of course on how you feel about doing it the hard way now to hopefully lower maintenance later on...

Don't skimp on the overhangs!

Thanks! So do you think collecting our rain water on a lime plaster roof would be safe?

can you not find some abandoned building and ...er ..find stuff ? Or advertise on Craigs list for roof tiles offering to remove them

The cement and mesh got me thinking:

There are hyperbolic roofs (aka. hypar-roof).

You start with a frame (probably wood) and add stripes of mesh. Then the mesh is painted with concrete (or anything else that works as a glue).
When finished, this roof is incredible strong (like the shell of an egg).

---
https://en.wikipedia.org/wiki/Hypar
http://flyingconcrete.com/hypar.htm
http://endeavourcentre.org/2013/07/hypar-roof-workshop-with-george-nez/

What's the house shape, dimensions, budget?
After the hard bagwork for a superior wall system, it'd be a shame to cheap out on your roof. Vigas kinda necessitate $$$ rigid insulation $$$ , where as some homemade trusses provide an attic cavity for duct work and cheaper blown in insulation...
If money is a huge concern, scour craigslist.