What happens when a spring is found under new construction?
In the Washington DC suburbs all the lots in a few counties have all been used for development, commercial or residential.
As such, in older neighborhoods, if one wants to live there, but not in the small house built there many decades ago, one buys the lot in a desired neighborhood, razes the former house, and builds a new house.
Many developers are doing this, buying all the houses on a street and building newer, larger homes, sometimes taking up two former lots.
Such was the case of this house. It was a 6500 sq ft home built in an older neighborhood in a Virginia suburb of DC.
During home inspections I sweep the entire house with my thermal camera, Mighty Mo.
This is what I saw in a finished basement room. The door on the top right corner goes to the furnace room. It is a large room, about 20'x30'
The blue you see indicates cooler temperatures, which, in this case, meant moisture. You can see that the wall and carpet were wet.
The moisture meter registered 100% moisture in the walls, and jumped to 30% on the wood, indicating that the moisture content exceeded 30%. The gage for wood only goes to 30% because wood is considered saturated at 28%.
Further, the moisture meter indicated 24% moisture in the sill plate in the furnace room, just about where the red and yellow meet in the wall in the thermal image above.
What did all this mean?
That basement wall hid a steel beam. It had four columns. The foundation wall supported it near the door in the image above.
The next support was a column about 2' to the left of where the red and yellow meet above. The problem was that the column was not visible, hidden by the walls of the room, the furnace room, and on the other side a staircase going to the middle level.
The base of the column, of course, passes through the basement slab, into the soil below.
My analysis was that water was percolating up from the base of the column to wick into the wood, wall and carpet nearby. The carpet in this house had only been there a week.
THAT IS A HUGE PROBLEM!
What to do? Obviously a geotechnical (soils) engineer needed to be called. His analysis? Water was percolating up from the base of the column to wick into the wood, wall and carpet nearby! Gee, the home inspector was right!
This house was built on top of a water source, likely a spring!
Prior to building soil needs to be studied to determine density, strength and moisture content. It has to support a structure, but also one doesn't want water infestation into a home. Was such a test done here?
The solution? Now a sump pump needs to be installed, separate from the other sump pump in the house. It will need to be located near the column, and plumbed to send the water outside of the house. At this point such an installation is not easy!
Would this problem have eventually been found? Yes, living in the property the homeowner would have felt the wet carpet at some point, or mold would have developed.
BUT THE HOME INSPECTOR FOUND IT BEFORE THEY MOVED IN! WITH A THERMAL CAMERA!
My recommendation: a thermal camera can be a crucial tool to use during a home inspection, and by a thermographer who is trained, certified and experienced. It is not point and shoot technology. A lot goes into device usage and image interpretation. This home inspector has had builders look him in the face and say home inspectors "should not be allowed to use thermal cameras." Unbelievable. Would you want to move into this house and inherit this problem? Mighty Mo wins again!