Problem - how do you extend an elevated concrete deck? Ours was not square, and had a huge notch in one corner. And - the steps were settling into the earth because they were installed without foundations below the frost line.
One of the most extensive projects we undertook at the house has been a patio refurbishment. The back patio off our family room is an elevated concrete slab with concrete sonotube columns supporting it from below the frost line. A very rugged structure that does not appear to have moved since construction of the house from 25 years ago.
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| Demolition of steps underway |
Also - very unattractive. Epoxy paint peeling. Massive 20' long concrete step was constructed on grade, and was settling / heaving with the frost. The shape was not rectangular, it had a large 45 degree corner cut from the shape which precluded the erection of a shade structure. And - it was not square to the house - it was square to the yard and pool.
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| Elevated Concrete Patio - Steps settling into the ground, shape not rectangular, corner cut at 45 degrees |
After much thought, we decided to keep the elevated concrete patio, but demolish the steps, square off the rectangular shape and make it a bit wider, and install a smaller set of concrete steps with foundations below the frost line.
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| Demolition of Steps Underway |
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| Demolition Complete |
With demolition underway, design of the concrete extension begun. I had engaged a concrete contractor to perform the work. They offered to perform the extension, but would not engage to produce any drawings or sketches. This posed a problem for building permits. I discussed the situation with our municipal planning department - they advised me that if I ever planned to construct a permanent structure on the patio, such as a sunroom or extension, they would require a structural design stamped by a professional engineer. So - I sought and found a civil / structural engineer that would prepare the extension plans - and I'm glad that I did. He recommended changing the extension thickness from 4" to 6", adding some additional screw piling suppports, and some additional rebar from what the concrete contractor proposed. Work then continued with the screw pile installation, selected to eliminate the requirement for large excavations to perform sonotubes and footings below the frost line.
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Screw pile installation.
The pile is literally screwed into the ground by the
hydraulic drive head installed on a mini-excavator. |
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| Completed screw pile, which will support the squared corner of the patio. Note the special head designed for supporting pour in place concrete. |
With screw piles installed, formwork and rebar began.
Cimentech was the concrete contractor. They did good work and I'm satisfied with the results.
Vistech performed the screw pile installation per the engineers recommendations - and I'm quite happy with their work as well - arrived when expected and performed the work very well.
Michel Kim was the civil engineer that prepared the structural drawing and documents for the building permit. He was a very practical engineer, and I think he was a big factor in improving the quality of the project.
