December 11, 2014 4:21 am
In our last report, I got the down-low on the pros and cons of building on, or purchasing a home constructed on a concrete slab. So in this segment, we'll go back to Andrew M. Dennis at Donan Solutions, a third-generation engineering firm that began in 1947 in Madisonville, KY, for his take on crawlspaces.
Dennis says the long-term performance of a crawlspace is greatly affected by the critical aspects of the presence of proper lot grading, adequate site surface water drainage, and a proper landscaping plan. And he adds that concrete slabs and crawlspace foundations present about the same number of advantages and disadvantages.
One advantage of building or buying a home with a crawlspace, is the heating and air conditioning ductwork and plumbing can be installed in it and be easily maintained. Any required repairs to these systems will be less expensive due to better accessibility.
A crawlspace elevates a house, Dennis notes, making it less susceptible to termite damage. And crawlspaces can be constructed on sloped lots using tiered concrete footings; however, the lot’s grading plan must provide adequate drainage to prevent damage from adverse surface water drainage.
Excess moisture in a crawlspace is a common occurrence and can have severe consequences if not addressed in a timely manner, Dennis points out. Stormwater and gutter overflow slopes toward the house and into the crawlspace and are sources of moisture that must be prevented or can damage the wood floor system above.
Dennis says a sheet of plastic with seams overlapped and taped works well as a vapor barrier to prevent the upward transmission of ground moisture. Adequate ventilation of the crawlspace must also be planned for and implemented in order to prevent the harmful effects that condensation can cause to the wood floor system above.
Dennis says the design and construction of either a concrete slab or conventional crawlspace foundation should be tailored to the geography and climatic conditions that it is expected to perform under.
Published with permission from RISMedia.