Watch out for drainage problems when doing your appraisals!!
When I first heard about the collapse of the Florida condo tower, I immediately thought about a drainage problem. Previous engineering reports revealed the problems – pool leaks, water not draining properly, etc. The condo building was constructed before building codes were changed to help avoid their problem. No one knows why the building started collapsing. Drainage Problems Can Damage Foundations
Limestone is under all of Florida. In parts of South Florida, the porous limestone is not good for foundations as there is less soil covering the limestone. I have seen many videos of saltwater intrusion flooding streets. The water came up through the limestone, caused by sea-level rise.
I always check for any drainage problems at homes. They are relatively easy to spot and can cause significant damage. I appraise many hillside homes, which can easily have problems. I look at where the gutter water drains and how it is moved away from the foundation. Sloping floors are another indication of possible foundation problems.
When I go into an unfinished basement, I look for water problems. One good indication is that everything is raised from the floor. Also, water stains on the lower part of the concrete. The water is coming through the foundation. A sump pump can help.
Properties I have appraised with obvious drainage problems:
– 2 story home on a hillside. Saw radiating cracks inside on both floors in the same corner. At the corner outside of the home was a small round drainage catchment about 1 ft. in diameter, without a way to drain it away from the house. The water came through the rear of the foundation because there was no drainage system.
– Home on a hillside that was moving down the hill. Standing water under the house. Unlevel floors. Big foundation cracks. Known area of problems. Relocation appraisal with two appraisers. The other appraiser did not mention anything.
Note: A good fix for hillside homes is a “french drain” in the ground that takes the water to the sides of the home, with plastic pipe to keep the water from the sides of the foundation.
– Duplex I own on a mostly level site. Tenants mentioned water coming inside the garage on one side. They had moved everything near that side of the garage off the floor. Both units were on level ground with raised foundations. The front garage was on a slight downslope. I replaced the gutters and drains so the water drained away from the foundation. I regularly check for any problems during the winter rains. No foundation damage, fortunately.
To read an excellent article on how and why concrete fails, Click here.
Modern concrete lifespan is roughly 50-100 years. The Florida condo building is 40 years old. “Concrete is poured around steel rebar, which gives it tensile strength. But tiny cracks — found in all concrete — cause water to start rusting the steel, which then expands, cracking the concrete.”
“Photos of the Surfside basement taken before the collapse show steel rebar breaking all the way through the concrete to the point at which it is fully exposed to the salty and humid Florida air.”
We definitely have a significant infrastructure problem. Replacing concrete is very expensive: building foundations, bridges, freeways, etc.
I have watched several documentaries about what happens if there are no humans to maintain buildings, roads, bridges, etc. The roofs fail first, and water comes inside. Concrete and steel are damaged by water. Roads break down. Bridges collapse. When doing appraisals, I always tell the owners to be sure their roof does not leak. When they see stains in the ceilings, the roof has already started leaking.