|Object Name||Field Notes|
|Title||Keim House addition cellar entry drawings|
Digital image of 2 field notes drawings and a series of 8 digital photographs showing the cellar entryway constructed in summer, 2011 at the c.1800-1820 addition to the Jacob Keim House.
During most of the past 90 years, the addition-cellar doorway and its approach [an earthen ramp] were sheltered against direct precipitation and roof runoff by the porch built in the early 20th century [photo #3676, 5/23/11].
Removal of the porch in July, 2011 eliminated the shelter it afforded, and exposed the cellar doorway and the ramped grade-path to direct precipitation and roof runoff, as well as ground-surface "sheet" flow to the doorway, a virtual "funnel" located at the low-grade along the southern foundation walls [photo #5310, 8/13/11]. Significant rainfall and the resulting surface-flow inundated the addition cellar between the time of removal of the porch and the installation of the retained cellar steps and pipe draining the paved lower landing of the new stair-block.
The stone stairway and retaining walls shown in the two sets of drawings and photographs in this record were designed to mitigate the ground and roof runoff into the addition cellar through this doorway. The integrated stair-wall structure consists of:
(a) a lower landing floored with flat stones ["flags"] laid in a random ["crazy"] paving pattern [photo #5642, 8/25/11, and #5804, 9/1/11]
(b) two intermediate steps formed by two stones ["treads"] each, with their inward faces constituting "risers" and
(c) two larger stones forming an upper landing and creating a natural riser, with treads level with the existing grade situated 24 inches above the lower landing paving.
The tread-stones and two-stone upper landing are supported on a "rubble" stone core set in mortar, and bedded several inches into the adjacent retaining walls, producing reciprocal mechanical bond and a strongly integrated stair-block.
The walls flanking the steps will serve the usual function of retaining the soils abutting the stairwell, and will provide the additional benefit of diverting the ground runoff around the entry-way to swales conducting the flow down-grade [to the south] from the yard area south of the house and federal-era addition [photo #5841, 9/3/11].
Roof runoff and direct precipitation into the "catch-basin" formed by the lower landing will be conducted to an absorption and discharge area by a solid 3-inch Schedule 40 PVC pipe extending at a ¼-inch pitch through the backfill and two retaining walls, to the lower grade 9 feet east of the cellar doorway.
The backfill around the new cellarway structure includes a bed of small stones serving as a "French" drain wrapped in a 4.5 gauge geo-textile filter fabric deployed to minimize clogging from soils above the stone drainage course. The water collected in this system will pass through the earlier retaining wall within the opening serving as the conduit for the drain pipe from the lower landing.
Tamped clay was back-filled against the building and retaining walls after insertion of a vertical sheet material forming a water barrier ["Delta-Drain"; see photo #5650, 8/26/11] to protect foundation mortar from disintegration. Mixed soils were then filled-in on top of the clay. The area will be sodded or seeded to inhibit erosion.
The as-built stair-wall structure is shown in photos #5834 and #5836, 9/3/11.
#3676: Doorway to addition cellar prior to removal of porch and construction of retaining walls and stone steps.
#5642: Retaining walls, steps and landings substantially completed, prior to leveling [“flushing”] up east retaining wall.
#5804: Both retaining walls leveled; Delta Drain membrane set in vertically against sub-grade stonework to conduct soil moisture to stone drainage course.
#5841: Rough grades and drainage swales established.
#5650: 3-inch stones back-filled as drainage path.
#5834 and #5836: Completed walls, steps and raked grades.
|Date||08/19/2011 & 08/23/2011|
Keim House Field Notes
Field Notes Drawing