Roof question: the tip-top

[David Nebenzahl]

So say a guy wants to build a polygonal structure. Say an 8-sided gazebo. When roofing it, how would he finish the very peak? Assume using asphalt composition shingles. No fancy ornament at the tip-top (weathervane or other dingleberry), but a neat peak is desired.

Is there a special cap you can buy for this? Like maybe a star-shaped deal? Or would he just cut some shingles and layer them to seal the peak?

Also curious how this would have been done around the turn of the (20th) century, using composition shingles available then.

[RicodJour]

Composition shingles of any type would be a poor fifth choice. Easiest way? Copper cap. If you don't like copper/green, lead-coated copper.

R

[aemeijers]

Ones I've seen, they capped with a copper or lead disc, either beaten or snipped/riveted into the appropriate shape. Not sure how they were held on- suppose they coulda been nailed with the heads covered with solder. Artful way would be with standing seams at each ridge line, crimped around a screwed-down bracket.

In modern cheap materials, I'd use a circle of that sticky-both-sides stuff similar to ice dam shield, and frost the top with matching granules from the roofing material dealer. Or maybe cut a suitable piece out of matching roll roofing, and try to do a neat seam just past a shadow line, and glue the sucker down.

Lotsa ways to do it and make it pretty, or at least not ugly. All depends on your budget and access to artisans.

I never had any reason to look, but I bet Simpson or somebody has a purpose-built cap available. Note that for a large tall gazebo, a vent at the top can make it a lot cooler inside in summer- chimney effect. Especially true if the sides get screened in.

[David Nebenzahl]

On 1/23/2011 5:56 PM RicodJour spake thus:

Doh! Of course, metal. I guess you can buy these in standard sizes. Me, being a nonreformable DIYer (plus a cheapskate), would probably try to make one out of sheet copper with snips, maybe make a wooden mandrel to smush the center into a peaked shape.

This is actually for a model, by the way, not a real structure.

[RicodJour]

There are several ways to do it, but pounding it into shape would be high up on my list of ways not to do it. Make one that fits out of paper/cardboard taped together, then slice one of the folds with a razor knife, open it up, add an allowance along the cut for a tab, lay it on a piece of copper and cut it out with snips, mark the folds and fold them crisply over a sharp corner of a metal angle, and it should close up to the proper shape. The tab will get soldered from the back to hold it together.

Alright. In future, you should probably point that out as it will unleash other solutions that are not possible in the full scale world. The above description is for a full size one. A HO scale one could easily be made from one piece that's scored along the fold lines and then bent carefully if the roof pitch is fairly shallow. If it's steep, I'd probably go with the first method.

R

[Joe]

For projects like that I just lay up some some fiberglass and boat resin. If the structure needs a simple form, it is easy to use Styrofoam as the basis, with epoxy as the resin (polyesters will 'melt' the Stryofoam. For adding details, good ol' Bondo works fine, can be sculpted to whatever you want, painted to suit.

Joe

[RicodJour]

You should mention UV inhibitors if you're talking about exposed fiberglass on a roof. In any event, regardless of the quality of the fiberglass work, a copper cap would last about, oh, I don't know - ten times as long, and it would take probably one quarter of the time to make.

R