Homeowner basics

Desert Southwest Homes: Heat, Monsoon & Caliche

What's different about building and remodeling in Mohave County and the desert Southwest: extreme heat, monsoon storms, caliche soil, and evaporative coolers vs. AC.

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Extreme heat

  • Outdoor work shifts early in summer; crews need water, shade and rest. The National Weather Service and Arizona DHS publish heat-illness warning signs.
  • Concrete: hot, windy weather speeds drying and cracking; ask about early pours, shade/wind breaks and curing compound.
  • Paint, caulk and adhesives have temperature limits on the label - ask your contractor how they'll schedule around them.
  • Attics get extremely hot - attic insulation and duct work is often scheduled for early mornings.
  • Roofing and siding materials expand in heat; follow manufacturer installation guides.

Monsoon season

In Arizona the monsoon runs from mid-June through the end of September, with heavy rain, strong winds, dust storms, lightning and flash floods (NWS, Arizona Emergency Information Network).

  • Plan tear-offs and open-roof work with a same-day dry-in plan
  • Clean roof drains/scuppers and gutters before the season
  • Grade soil away from the house; keep drywells clear
  • Patio covers, shade structures and fences should be built for local wind loads - ask what they're designed for
  • Walk the house after big storms and photograph any damage

Caliche soil

Caliche is soil cemented together by calcium carbonate. It can show up as lumps or as a solid, rock-like layer from a few inches to several feet thick (University of Arizona Cooperative Extension). It affects digging, drainage and planting.

  • Expect a rock/caliche clause in excavation, footing and fence bids - ask for a unit price.
  • Tree and shrub holes need a drainage path through caliche, or water pools and roots drown.
  • Footings and post holes may need equipment like jackhammers or augers - which adds time.
  • Drainage: water may run along a caliche layer instead of soaking in; plan grading carefully.

Evaporative (swamp) coolers vs. air conditioning

  • Evaporative coolers work best when outdoor humidity is low. The DOE's Building America Solution Center says they can use about one-fourth the energy of central air conditioners and cost less to install and operate in dry climates.
  • They add moisture and need open windows or relief vents; they don't work as well during humid monsoon days.
  • They need regular maintenance - pads, pump, water pan - and should be drained in winter.
  • Central AC or heat pumps cool and dehumidify regardless of humidity but cost more to run. Proper sizing (a load calculation) matters.
  • Many desert homes use both. Ask your HVAC contractor to explain costs for your house.

Water & landscaping

  • Desert-adapted plants and drip irrigation save water
  • Set irrigation controllers by season
  • Check local water rules

Local help

Corky's MHS is based in Mohave Valley, AZ. Ask a desert-specific question at the Contractor's Desk ($5), or price a cooling or landscaping job in the calculator.

Sources

External sites open in a new tab; Corky's MHS™ is not affiliated with them. Statutes and agency pages change - check the current version.

Please note

Educational information only - not legal, engineering or code advice. Rules vary by state, county and city, and change over time. Check with your local building department and licensing board, and read your own contract.