12.2 - 1614 Preston Ave - Contractor Letter on Masonry — original pdf

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August 20, 2026 Historic Preservation Office City of Austin, Texas preservation@austintexas.gov RE: Condition of Existing Masonry at 1614 Preston Avenue, Austin, Texas 78703 Mr. Lukes and Members of the Historic Landmark Commission, I am the general contractor for the proposed renovation and second-story addition at 1614 Preston Avenue. I have over 20 years of experience in residential construction in Austin and Central Texas, including work on homes of this era, and with the kinds of masonry challenges present at 1614 Preston. This letter details my professional assessment of the condition of the existing masonry, the origin of the present issues, and my recommendation. On the structural questions, I have relied on the concurring opinion of the project’s structural engineer, Bradley Shaw. The existing stone masonry at 1614 Preston does not extend around the building. The stone is present on the front and along a little more than half of the left side. The remaining walls are not stone- clad. In my assessment, significant portions of this masonry do not appear original to the 1939 structure. This is most apparent at the chimney and along the Jefferson Street side. This conclusion is based on the variation in the stone’s cut and color, differences in coursing and mortar, and the way the stonework terminates, particularly at and around the chimney and the earlier addition area. These observations are consistent with the property’s other evidence of prior additions, as well as the structural engineer’s findings. The existing masonry is deteriorating and cannot be reliably stabilized. I observe cracking and displacement within the stonework, failed mortar joints, and clear evidence of chronic moisture intrusion. This evidence includes staining, dampness, and heavy biofilm growth in areas that appear to remain persistently wet rather than occasionally damp. The concentration of biofilm at grade and across the lower half of the wall is consistent with water collecting and remaining at the base of the wall, from ground contact, splashback, and the lack of appropriate base flashing. At the chimney, the biofilm marks sustained water entry at a junction that is a common source of leaks. Mortar loss and stone decay are most advanced in these same areas. In my experience, the cause is most often the manner of construction. A masonry wall always takes on some water. Without sufficient weather-resistive barriers, drainage cavities, flashing, or weep systems, water is held against the back of the stone and the structure behind it. The condition of the masonry at 1614 Preston is consistent with this kind of prolonged moisture exposure. A second contributing cause is the structure’s mixed foundation, part original pier-and-beam and part later slab additions, which have settled unevenly and stressed the stone. Very little movement is required to crack stone of this kind. The project’s structural engineer concurs that this differential foundation movement has contributed to the poor condition of the masonry. I considered the usual repairs for masonry in this condition, including repointing joints, resetting displaced stones, rebuilding the worst sections, and improving exterior drainage. However, none of these repairs address the underlying issue, that the wall has an insufficient drainage plane behind the stone, so water remains trapped and decay continues. Correcting this issue requires remediation of the wall assembly, which requires removal of the stone. Leveling and reinforcing of the foundation are included within the project proposal and will stop further movement but will add no moisture protection behind any stone that is left in place. Left in place, the masonry will continue admitting water, where it poses a risk to the wood framing and sheathing of the structure and foundation. Over time, this persistent moisture will lead to rot and structural damage, as well as a loosening stone veneer which will become a fall hazard. On the basis of the conditions described, I recommend removing the deteriorated masonry and re- cladding the affected areas with a stucco system. A stucco system can be installed over a proper weather-resistive barrier and drainage cavity, with control joints for the structure’s movement, so that water is managed instead of trapped. I understand that the Historic Preservation Office indicated support for a stucco treatment during the owner’s preliminary review meeting, as well. I would be glad to provide additional detail, or to meet at the property to confirm findings as may be required, at the Commission’s convenience. Respectfully, ________________________ J. Brenton Christian Bespoke Design Build 8610 Buffalo Trail Lago Vista, Texas 78645 (512) 785-2706 In Consultation With Bradley W. Shaw Highland Lakes Engineering PO Box 1164 Kingsland, Texas 78639 (830) 637-9584