This method of drilling, arranging and nailing disks works great for any roofing that has wooden board underneath. Structures like sheds, dog houses, lean-tos and porches are easy to cover and it makes a great hard-wearing, long lasting (I hope), cheap and most importantly.... green, method of roofing.
CDs and DVDs are readily available if you scrounge around. Ask friends, post on local sites like freecycle or craigslist, ads in the free local paper; these ways soon add up to thousands if you're happy to do a little walking/cycling around your town to pick them up.
Using this method, you need as few as 120 disks per square meter, and the method of drilling and arranging used means no water runs through the holes in the CD!
Step 1: Pros and Cons
If you've got old disks you want to get rid of, first think whether there might be someone able to reuse them before drilling holes in them and tacking them to your shed roof! Software, music and films might be of interest to your friends or families and are often accepted by charity shops as a good product to sell on.
For junk mail CDs and badly damaged or scratched CDs/DVDs, it is better to reuse them than throw them away or recycle them. If they can be of use for another 5 years before needing to be replaced then that's better than transporting them to a recycling plant to be melted down and MUCH better than them just taking a trip to landfill. Landfill is a dark, scary place!
Step 2: Disk Arrangement
It may look complicated at first but once you grasp how to arrange them, it's pretty easy! The animated gif below should help. The second picture illustrates how the drilled hole aligns to the disk below, it narrowly misses the disk, covering the hole below. The third picture is my first correct attempt at arranging them on my living room floor (without the nails of course).
Step 3: Drilling Jig
I found that the hole should be drilled anywhere on the ring where the central clear area meets the foil. This will allow you to nail through the CD without the CD below it needing a hole in it. The pictures should explain better than I can.
A stack of disks can be push into the jig once the drill bit is centered on the cross, at which point 10 or more disks can be drilled at a time, tipped out and then another load done. Easy!
If you don't have a pillar drill, build the same jig then screw a baton across the top with a hole in it in the right place through which to stick your bit. This should be equally quick. I ended up using my Dremel with a plunge attachment and a 3mm metal bit.
Step 4: Drilling
The loose block of wood you can see in the photo is to knock all of the disks into the correct alignment.
Once aligned correctly, drill through the disks quickly, in several plunging motions. Once all the way through all disks, remove them from the jig as soon as possible. They will have melted together slightly from the heat of the bit. Separate them from each other with a twisting motion. Before I worked this out I tried to prise them apart and cracked a few.
Step 5: To Shine or Not to Shine?
Some advantages to shiny side up:
- Might keep your dog house or shed cooler in the summer months, always a plus!
- The CDs might last longer if they reflect some of the UV rays, we'll see!
Some disadvantages of shiny side up:
- May annoy the neighbors when the sun's low.
- Some might think it looks silly!
Step 6: Nailing
For the first layer at the bottom, lay the disks out first before you start nailing to make sure you get the alignment right.
To avoid crushed fingers I found I could push the tacs in to start with then once they stood up unaided, hammer them home with a couple of taps of the hammer. I expected splitting of the disks to be a problem, but it didn't seem to be.
Start at the bottom and work your way up, being careful to cover the holes as explained in step 2.
To nail all 135 to the board took me only 50 minutes. A lot slower than roofing with roofing felt, but a lot cooler and greener too!
Step 7: Longevity
I have some concerns about the ability of CDs and DVDs to hold up against frost and UV. If you'd like to be kept up to date with how they're holding up, please subscribe to me. I will post a forum topic in April once the frosts are over and then again in August after it's been out in the sun all summer.
April Update: (remind me if I haven't posted it by May 2010)