Construction Advice for a Hillhouse in a Very Hot climate with Moderate Winters!



1- I'm thinking of building a house in the mountains close to a major
city because the city is unbearably hot in summers with typical
temperatures ranging between 40 and 50 degrees Celsius.

2- The highest elevation that I can find in the surrounding mountains is
4,500ft, which translates into a temperature gradient of around 9
degrees Celsius, so it wouldn't be too bad at 30 degrees Celsius on some

3- I want solid long-term, low-maintenance, aesthetic construction:

1- For construction of the walls, I've ruled put wood even though it is
the best insulator because of issues with maintenance against termites.
I'm in not in favor of bricks because of issues with mold. I've also
ruled out air-concrete because of its poor aesthetics and requirement
for paint or another facing, so this leaves me with sandstone as the
most likely material with a thermal admittance of 1.83 vs 0.14 for wood,
0.73 for brick, and 0.15 for air-concrete. All have a specific heat
capacity of around 1000 J/ Kg.K. Wood is at 1200, stone is at 1000, an
air-concrete also at 1000, whereas brick at 800, but the sizes and the
weights even the differences out, so this turns somewhat irrelevant.

a- Am I making the right choice with the sandstone because it would be
much broader and heavier, so would somewhat offset the low admittance of the other materials, whereas it would also translate into a higher
weight for a higher overall thermal mass, so would further inhibit
conduction into the house, and could radiate most it back to the
environs in the evening, with which it would have the highest
temperature gradient.

2- I wanted to use slate for the floor, but that would turn it too
monotonous, considering the very similar colors, so could use a much
varied granite, marble or wood for the floor. Any other options, people
on the board could suggest?

I’m against using an air-gap between two columns of stone-blocks, which
could be a better insulator than Styrofoam because of potential water

3- I don't want to risk a weak or flat roof because of the rainfall and
very little, but still some snow in the winters, so I have decided on an
inner A-frame RCC roof.

Since the weather is extremely hot, I'm against tiles with air-channels
because those aren't very effective, so I would need to place a lighter
outer-roof over this at a distance of 6-inches to 1-ft to prevent the
conduction of heat through the roof and its cooling via air currents.

This is where I need your advice. A galvanized, corrugated, steel roof
would reflect and radiate heat to prevent its conduction through the
roof, but would eventually rust. Could you suggest slate, shingles or
other options, provided they come in naturally reflective light colors;
but these would still need a concrete or metal support structure to add
to the cost?

I have tried to use Styrofoam for the insulation of the roof in the
past, in another house, but the heat here is so intense that the effect
was insignificant. I’ve also tried a false internal, ceramic ceiling,
in another home, but without adequate ventilation for either the foam
layer or the false internal-ceiling to use convection currents to expel
the heat, none are very effective, and convection opens up the prospect
of leaks and accumulation of irregular pools of water without effective
channels for its drainage, so, for now, an inner weight-bearing roof
and an outer Sun-blocking, reflecting and heat-radiating roof seem the
best options. Would any of you wish to offer your opinions?

4- To block the noon-Sun during the day, I intend to construct a veranda
with a sloping roof around the side facing the Sun on the South, as in
British colonial construction, and could additionally even use wooden
shutters or cane curtains to block the Sun.

5- For ventilation, I intend to use large windows with high, roof-mounted ventilators to create a natural duct to draw cold air from the north, at the floor level, and expel hot air to the south, at the
roof level. I could use twin sheets of glass with an-air gap and,
perhaps, even a PVC shutter with a wood-grain. I could also use exhaust
fans to artificially reinforce the currents or desert coolers for
evaporative cooling. The place is remote, so doesn’t have electricity,
which means I can’t use air-conditioners with solar panels because I’d
typically need around 120,000 to 150,000 BTU to cool the entire house.
Any suggestions here?

6- Because of downpours and mild-snow in winters, I can't really afford
to build a part of the house into a hill for insulation, as it would
raise issues of rainwater getting into the foundations and the walls,
even if I build channels around it because they could get blocked with
leaves, stones, mud and other debris.

7- I'd leave the discussion of a heat pump with the compressor driven by
the heat of the Sun or boiling water, instead of electricity, for a
later day. I also don't want to discuss geothermal heating and cooling
at this early juncture of a preliminary design.

Could you provide me with additional ideas to improve on this or,
perhaps, even redo it?

Sep 29, 22 8:37 pm

Hire an architect. If you provide your location the membership here will gladly assist in finding you a qualified one. 

Sep 29, 22 8:45 pm  · 
2  · 

Right? That narrative, tl/dr, is impressive, but still needs to hire a professional.

Sep 29, 22 8:56 pm  · 

What stone is available in the local mountains where you want to build your house - that would seem a first consideration? Same for the types of wood available. More consideration should be given to the orientation of the veranda. In the northern hemisphere in the summer the sun sets in the northwest. A south facing patio will be shaded by the house in the late afternoon in the summer. In the American Southwest, especially the Texas Hill Country, many houses were made of thick limestone walls and small windows to help control the heat gain and loss. I would study those thoroughly. 

Sep 30, 22 7:41 am  · 

You need to hire an architect.  

Sep 30, 22 10:42 am  · 
3  · 

I would recommend hiring an architect before you buy the land, to advise on the orientation of the land.  The slope, exposure orientation, top vs bottom of hillside, vegetation, etc will have as much impact as the materials.   Mountain microclimates, sun, wind conditions, etc. vary greatly in very short distances.   I’d also bring in a good landscape company to make sure that you are maximizing the potential of the land and minimizing impact on the nature terrain and ecology.  

Nov 24, 22 12:38 pm  · 

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