This is a trick question because you can’t really straighten these walls; we can only hope to stabilize them and minimize any future movement. Theoretically, a stone house should last for centuries and they often do in varying states of being level and square. Foundations settle, walls tip inward and walls tip outward and the Crockett Street House has all of the above. In areas that show visible cracking and shifting, the unsecured roof structure has put point loads and thrust on the stone walls. The southeast corner still has slight twisting and separation from a wall failure that occurred 30 years ago. The failed wall and the area immediately adjacent to it were repaired but a wall intersection about 2’-4’ beyond need reinforcing. Earlier this fall we reinforced and tied together the wood framing systems including the roof and now we’re taking care of the tops of the caliche limestone walls.
It’s common here in Central Texas and the Hill Country to see high ceiling buildings with steel tie rods spanning from one end of the building interior to the other end. They’re held in place with steel plates on the exterior wall – and in these parts, it’s been a source of pride to use the “lone” star. When you see a star or plate on the outside of an historic brick or stone building (turn of the previous century and before), there’s a 99% chance that it’s connected to a steel tie rod on the inside of the building holding the walls inward. One of the original tie rod plates that was put into place during the house’s original construction can be seen on the south elevation. If you look closely below, you’ll see the star about 18” from the corner of the wall that secures a tie rod along the north-south wall in that location. The grayish plates are the new ones we’ve just installed.
Because caliche is so soft, using tie rods throughout for stability would not be the ideal method of tying together this house, therefore, we chose to use a solid and continuous steel plates on the interior walls and they’re secured in key locations. Each of the 3 rooms gets a plate assembly and the 3 rooms are then tied to each other. It works sort of like dental braces, but the banding is on the inside of the room rather than the outside of the house.
The tall gable walls that support the 12:12 roof will get 2 tie rods each. They’re doing a different job than the plate banding and will be anchored in the attic space. I’ll just say, I’m not particularly fond of the star plate so we chose to use a functional rectangular plate as the terminal for the stainless steel pins. This shape will be easily covered or camouflaged with stucco or a paint finish at the end of the project.
Our mason is incredibly experienced in limestone buildings and as a result is fluent in the structural system including how it interfaces with steel and wood structures. Baltazar Espinosa has been doing this type of work for decades and I would use no one else.
Espinosa knows that this soft stone requires a careful hand and trusts his apprenticing son Rick to machine and install the steel plates.
On the inside of the house we’ll leave the heavy duty steel and use it as part of the cornice trim or picture rail – it’s way too cool to cover up!
Once this work is completed, we’ll be moving to the outside of the house to completely rehabilitate the 2 wooden porches and parts of the roof! Spring 2014 will be a great time for the Crockett Street House!