What, if anything, is wrong with a gable underground house?

OK, so I have a hillside. I excavate out a flat area so it ends up being about 8 feet vertical at the back. The back is tiered like Mike Oehler recommended. A simple gable ended house, front and back, is built on the excavated ground. The roof pitch is approximately 2 to 12 or slightly less.  Suitable structure to resist backfill and waterproofing are applied to the two sides and roof along with French drains along the back and sides. A PVC drain tile exits down the hillside a bit. The house is backfilled along both sides of the house and the roof is bermed. One gable end looks downhill and the other gable end opens onto the uphill patio.

Is there anything wrong with this design? Like always, my main concern is drainage. I want to keep the roofline as simple as possible and not mix a shed roof with a gable. I want to have just the gable the whole way from the front to the rear of the house.

Thanks Y'all
(Native Texan)

Seems pretty much ideal to me. Drainage goes off where it is safe, daylight exposure is maximized. Side walls can be short because the ceiling rises to the middle - put storage or minor functions at the (dark) sides. 24' wide @ 2:12 = 7' walls, 9' centerline. Cozy but not cramped.

Jp Wagner wrote:OK, so I have a hillside. I excavate out a flat area so it ends up being about 8 feet vertical at the back. The back is tiered like Mike Oehler recommended. A simple gable ended house, front and back, is built on the excavated ground. The roof pitch is approximately 2 to 12 or slightly less.  Suitable structure to resist backfill and waterproofing are applied to the two sides and roof along with French drains along the back and sides. A PVC drain tile exits down the hillside a bit. The house is backfilled along both sides of the house and the roof is bermed. One gable end looks downhill and the other gable end opens onto the uphill patio.

Is there anything wrong with this design? Like always, my main concern is drainage. I want to keep the roofline as simple as possible and not mix a shed roof with a gable. I want to have just the gable the whole way from the front to the rear of the house.

Thanks Y'all
(Native Texan)

The only problem I can see is with a gable roof, you are draining your roof water down to the sides of the house, rather than downhill.  Mike was very specific that the water should always drain downhill.

With reasonable finish grading, it would be draining downhill at least to 6-10' from the sides, at which point "downhill" changes direction. A reasonable thermal umbrella would keep water away from walls, and drainage would at worst be flowing parallel to the umbrella zone edges.

Glenn Herbert wrote:With reasonable finish grading, it would be draining downhill at least to 6-10' from the sides, at which point "downhill" changes direction. A reasonable thermal umbrella would keep water away from walls, and drainage would at worst be flowing parallel to the umbrella zone edges.

It matters a lot if we are talking about an Oehler-style underground structure or a wofati, at least to my limited understanding.  Mike's structures didn't really have any finish grading, or a thermal umbrella, so shunting water downhill was always the biggest concern.  The roof always followed the slope of the hill so that every drop of water hitting the "roof" went directly downhill.  If you build a structure with a large umbrella over the it, you have much more freedom with it I would think.  

I haven't studied Oehler house design much, but unless you take pains to have the roof match original grade and elevation, the dirt dug up for the house has to go somewhere, and next to the house seems easiest; this would raise local grade and cause some degree of slope away from the sides. If it is not practical to slope the grade away from the sides, you have chosen a bad place to build. (Local surface should be convex, not concave.)