Dragon Scale Shingles

Years ago I saw a picture on the back of Fine Homebuilding of a backyard building that had a conical roof covered with shingles cut in an organic wavy pattern.  It looked almost thatched or as if it was covered in scales (Dragon Scales?!?).

 At the time I didn't need any roofs for circular buildings but I thought - I could make that and I definitely should if the opportunity arises.  I mentally filed the idea away for future coolness.  Fast forward 15+ years and what do you know?  I've got a circular building that needs a roof!

 The scaly shingle idea wasn't a winner in my wife's mind though.  She never saw the original picture and I guess I wasn't selling my version very well because I never got more than a lukewarm reception to it.  We pondered many ideas for roofing material including used tires or recycled highway signs cut into shingles.   I couldn't shake the vision of that back cover though and in the end the dragon scale idea prevailed.

First, you need to calculate the area that you are going to be covering.  If you want, you can be precise and follow the formula in the picture to calculate your roof's area...OR...you can be lazy like me and if there isn't much of a pitch to your roof figure it as a circle and add a bit for height.  (Actually, I just got started and kept buying material as I went)  Because the shingles overlap quite a bit you need to figure on enough material to cover your roof twice at least.  So if you found that you had a roof that was 100 sf you will need roughly 200 sf of roofing material. 

Next, the decision is yours go with real dragon scales or an alternative?  I didn't have any dragons that happened to be shedding available so I chose to go with the next best thing- rolled roofing.  It’s an asphalt material that comes in three foot wide rolls and is one of the cheapest roofing materials per square foot you can use to cover your roof with. You can get it at any big box store.

The only other thing you need is roofing nails.  They are short galvanized nails and you are going to be using a bunch of them.  How many is hard to estimate but you'll get a feel for it as you get into the project.

The tools I used are pretty simple - 

Sheetrock T-square 
Tape measure
Carpenter's pencils- several of these
Tin snips for cutting the roofing
Hammer
Carpenter's tool belt to hold the nails 

My approach was to make 8' x 1' sections with a wavy edge as my starting pieces and then cut them down to fit once I was on the roof. The first thing I did was to cut a piece of roofing at 8' then I divided it with pencil lines into three 1' strips.  Next, I drew a wavy line down the middle of one of the lines and another one along the edge of the remaining strip.  (See the pictures)
 
I cut the pieces out and saved my favorite one to use as a template for the rest. Going forwards it was just a matter of laying the template down on each 8' section of roofing and tracing it.
 
Metal shears work the best for cutting the roofing.  Working at a table is a good idea as this will take many hours.  Your back will thank you.  Getting help here is a good idea too.  My wife and I worked it out so that she was cutting strips while I was up on the roof installing them.

I had already covered the roof with an underlayment of Grace ice & water seal.  You could also use tar paper. The underlayment is an extra layer of protection in case any water gets through the shingles.

Installing the shingles is a matter of fitting the strips into concentric overlapping rings nailing down the shingles as you go.   It is a bit of an art to get the pattern of the wavy edges to look good.  There is a lot of fitting and trimming involved to get it right.  Be patient and take your time.  Nail along the top edge of each strip at 6" intervals.  Make sure that each overlapping layer covers the nails of the one below it.

In addition to cutting the 8′ strips smaller to fit, I found that I also needed to insert small sections of shingle in random spots to add to the pattern and hide wayward nails.  Where the ends of the shingles came together I trimmed them so that they were rounded and overlapped them so that the prevailing wind would not peel them off in a storm.