Expert: Bruce E. Johnson - 3/5/2010

Question
Hi,
I'm building a home in Ghana West Africa. The readily available building material is concrete. The building techniques are archaic mostly poured in place walls on the poured-in-place slab foundation. My living experience is it becomes unbearably hot at night because of the heat absorbed by the structure during the day. How do we minimize this or eliminate this? Remember Ghana is a "developing" 3rd world country without as many options as the USA has.
Thanks.

Answer
Hi Akos, one of the simplest ways to keep exterior walls from heating up during hot days is to create large enough overhanging eaves to keep the sunlight from directly hitting the walls during the day. This is one of the reasons for wrap around porches in tropical climates.  The exterior porch roof keeps the sunlight off the walls. If the concrete remains in shadows then it is less likely to heat up.  Also the lighter the color your roofing material and wall paint.  White reflects light and subsequent heat, darker colors absorb light and subsequent heat. Hip roofs are best because they have eaves all the way around the house as opposed to gable end roofs that have no overhang protection from the sun's rays. Insulation is another option but I am not sure what types of insulation are available in your area.  By adding insulation to the inside of your exterior walls you can help keep the heat transference down to a minimum.  Attic insulation is extremely important in hot climates.  The inside temperature of the attic space can reach 180 degrees in some climates making sure this heat is allowed to escape through vents is important as well.  I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com