In AZ few homes have gutters. We don’t have any. We do have a patio with cover, and there are scuppers to drain that cover. I was thinking it might be useful to have something mounted on the roof tiles that directed more roof water to the patio cover. Is there such a thing? I can find lots of gutters, but those mount on the eaves, not on the roof itself. Just thinking about controlling where water drains around the house.
A concrete drip-strip on one side of the house. It was about 12 inches wide and ran the length of the porch, 62 feet. It was a shallow “V” shape, about 1 1/2 inches deep at the center. It was high at the center of the house and sloped about 4 inches from the center to each end. One end went to gravel and away from the house. The other end went about 4 feet then into a 4 inch drain tile that carried the water about 50 feet under plantings and a parking area to an open air drop.
On the other side of the house, we had a relatively steep slope. After a year I noticed the heavy rains were pounding the dirt and eroding it. I set a bunch of limestone rock (left over from building the walls) all along the 62 feet of porch on that side. I pitched them at 30-ish degrees and had 12 to 18 inches of width. No more problems for the next 15 years.
If you are not going to use gutters, I would:
A. Never make more holes in the roof to mount diverters. Every hole is a future failure point.
B. Add more water load onto another roof.
C. Control it at ground level using hard surfaces in the drop zone and durable materials to carry it away from the house.
On the house we are building, we have one roof penetration for the plumbing vent. All will be collected to one stack.
Everything else goes to:
A side wall: furnace in/out, air exchanger in/out, 1 bathroom vent out and the dryer vent out.
A soffit: kitchen range hood out and 2 upstairs bathrooms out.
Anyway, if you have/find a good roof or gutter person, they may help with designing some diverters, whether using tile material or if not in plain site, some aluminum/gutter material that they attach to the roof to push the water in preferred directions.
Gutter guys here sometimes put in a small diverter where the water is flowing on the roof/shingles, but directed (usually away from walls or the house and towards a gutter area) by a small strip of aluminum attached to the shingles.
If you have hard rains (I live in Florida, so, every season), be wary of creating inadvertent pooling/pressure points that your roof can’t handle or that would create a maintenance headache in the future.
We had a whole new roof put on several years ago when we added to the home. We had gutters all removed, but made sure we had 30 inches or more of special watertight stuff affixed to the edges of the roof everywhere (to protect against possible ice dames, etc.) and the usual drip edge. We also had ridge venting added so air can leak out and keep the attic cold.
It’s been great. No more gutters to clean (and we oak and maple trees overhanging the house)and no other troubles up there. Thankfully, the original builder did a great job of drainage all around the foundation, too.