Sandstone on top, limestone on the way down
Signal Mountain stands on Walden Ridge, part of the Cumberland Plateau. The plateau's surface is capped with sandstone, shale and conglomerate, which the U.S. Geological Survey describes as generally unaffected by the dissolving that produces sinkholes in the valley. The same source notes that limestone crops out along the escarpments, where most of the plateau's caves and springs are found.
So a house on the flat top of the mountain and a house on the brow or the mountainside road are in different situations. Up top, the questions are about slope, fill and drainage. On the way down, limestone and the water moving through it come back into the picture.
What steep lots do to foundations
- Tall downhill walls. The low side of the house may have ten feet or more of foundation wall exposed, carrying load and resisting soil at once.
- Cut and fill. The level pad the house sits on was made by moving soil. The filled side settles more than the cut side.
- Fast runoff. Water crosses a steep lot quickly and scours soil from under footings, steps and deck posts.
- Retaining walls. Driveway and terrace walls hold the lot in shape. When one leans, the ground behind the house can follow.
A wall that has started to lean is covered on the page about bowing basement walls.
Town of Signal Mountain, Building and Codes
1111 Ridgeway Avenue, Signal Mountain
(423) 886-2177
The town's permit page says a building permit is required for any structure being built, changed or modified, and names crawl space encapsulations in its list alongside decks and remodels. The homeowner is allowed to pull the building permit.
Signal Mountain or Walden?
Two towns share the mountain, and mail addressed to Signal Mountain reaches both. The Town of Walden does not carry out its own inspections or issue construction permits; Hamilton County Building Inspection does that for Walden, at (423) 209-7860, and for the unincorporated parts of the mountain. Find out which you are in before the contractor applies, because an application sent to the wrong office costs time.
Getting equipment to the house
Access shapes repairs here more than anywhere else in the area. A narrow drive, a steep yard and mature trees can rule out machinery, which means hand-dug excavation and piers installed with portable equipment. Describe the approach to the house when you call, and send photos if the company asks. It saves a wasted trip.