Ornamental plaster dome
in Washington, DC

Slide show. How we did it:

We started with an octagaonal hole in the ceiling.

We started with an octagaonal hole in the ceiling.

I cut the template with a router.

I cut the template with a router..

 Next, I screwed 1 x 6's to the bottom of the octagon. This provides a track for the template.

Next, I screwed 1 x 6's to the bottom of the octagon. This provides a track for the template.

Then, I screwed a 2 x 8 to the skylight framing, drilled the center, and put in a long bolt.

Then, I screwed a 2 x 8 to the skylight framing, drilled the center, and put in a long bolt.

Water damage.

A "shoe" is attached to the bottom of the template. This keeps the template from wobbling on the track.

1 by blocks are screwed to the track. These hold the joints in alignment.

1 by blocks are screwed to the track. These hold the joints in alignment.

Template finished and bolted to the support on the skylight.

Template finished and bolted to the support on the skylight.

3/4 inch channel iron is bent using a template for a guide

3/4" channel iron is bent using a template for a guide

3/4 iron is screwed to the octagon.

3/4" iron is screwed to the octagon.

1-1/2 inch channel iron is bent in a circle a tied to the 3/4 inch iron

1-1/2" channel iron is bent in a circle a tied to the 3/4" iron

Eye hooks are screwed into the joists. 1-1/2 inch iron is tied with 9 gage hanger wire. There are 4 hanger wires.

Eye hooks are screwed into the joists. 1-1/2" iron is tied with 9 gage hanger wire. There are 4 hanger wires.

1-1/2 iron is screwed to the skylight framing. Then 3/4 iron legs are tied on.

1-1/2" iron is screwed to the skylight framing. Then 3/4" iron legs are tied on.

Metal lath is tied to the 3/4 inch iron.

Metal lath is tied to the 3/4" iron.

Framing and lathing finished.

Framing and lathing finished.

Fast forward to the finished dome.

Fast forward to the finished dome.

Dome is filled with moulding plaster and lime while template is rotated.

Dome is filled with moulding plaster and lime while template is rotated.

Dome is shaping up a little at a time.

Dome is shaping up a little at a time.

Template pushed around.

Template pushed around.

We mixed mortar on two mortar boards and passed it up.

We mixed mortar on two mortar boards and passed it up.

Template removed, dome is troweled smooth.

Template removed, dome is troweled smooth.

Dome almost finished. Note how thick it is.

Dome almost finished. Note how thick it is.

The top of the oculus is trued up by laying one by material the top and filling in.

The top of the oculus is trued up by laying one by material the top and filling in.

Now all there is left is to fill in catfaces.

Now all there is left is to fill in catfaces.

Ceiling is filled in with metal lath and plaster.

Ceiling is filled in with metal lath and plaster.

Filling in ceiling

Filling in ceiling

Finished dome.

Finished dome.