RDH Building Sciences Inc.

Transcription

1 MAK LTR Proposal for Building Enclosure Consulting Services RDH Building Sciences Inc. 509 FAIRVIEW AVENUE N SEATTLE WA TEL FAX [email protected] TO Ann-Marie Lindboe Roxanne Navrides Seattle Housing Authority B Leschi House 120 Sixth Avenue North P.O. Box Seattle, WA February [email protected] [email protected] REGARDING Repair Recommendations and Opinions of Probable Costs Dear Ann-Marie and Roxanne, Following is a summary of our recommendations and opinions of probable costs for Leschi House. All recommended repairs contained in this letter require further investigation and repair design prior to implementation. Item Number Summary of Work Item Probable Cost Opinions (See description of condition and work item below.) Opinion of Probable Cost 1 Re-clad entire building with rainscreen cladding assemblies and details. Repair sheathing and framing where required. Contingency for damage included. $1,088,000 2 Replace all windows. $166,000 3 Restore seals of community room skylight. $13,000 Total Near Term Work $1.267,000 PROJECT OVERVIEW Leschi House, located on the south side of S Weller St, east of 10 th Ave S, is a circa 1986, 4- story wood frame multi-family building. The exterior is clad with stucco and accented with pot balconies, and balconies at each floor s common area. The roof is flat with a mineral surface S:\B Leschi House\Report\B Leschi House Report mvh.doc page 1 of 4

2 RDH Building Sciences Inc. cap sheet. All Leschi House facades are exposed, unprotected by adjacent buildings or overhangs. Individual living units have horizontal sliding aluminum framed windows with insulating glass. Large fixed-lite aluminum framed windows exist at the east entrance and around the community room areas. Seattle Housing Authority carpenters assisted RDH on November 7 th and 8 th, 2007 to conduct a limited invasive investigation of the Leschi House building envelope. In addition to this invasive investigation, RDH met with Leschi House staff and discussed reported leaks and maintenance issues. RDH also met with SHA maintenance personnel who reported that problems with leaks at Leschi House are ongoing since the original construction and building occupancy. SITE OBSERVATIONS 1. Moisture related damage exists at 19 of 31 locations where openings were made in the stucco around the building (Photos 1 5). The discovered and reported damage locations are related to approximately 35% of the stucco cladding. In other locations where openings were made, framing lacked damage but water was found between the back of the stucco and the face of the building paper water resistive barrier (WRB) (Photo 6) 2. Sill dam test were conducted on 10 windows; 6 of the 10 windows tested leak. In addition, residents reported, and we observed signs of substantial leaks at 6 other windows at upper and lower levels (Photos 7 & 8). Typically, water damage exists at the lower corners of these leaking windows (Photos 9 & 10). Signs of substantial moisture intrusion exist at unit interiors (Photo 11). 3. Above the entry vestibule, water leaks from upper floor windows and into the roof assembly (Photos 12-14). 4. Evidence of water leaks exists at 4 of the scuppers at the head of downspouts (Photos 15). All scuppers are attached directly to the sheathing before the stucco was applied, allowing moisture intrusion. 5. Leaks exist at the Community Room skylight (Photos 16 & 17). EXTERIOR CLADDING ELEMENTS Lack of Weather Resistive Barrier Continuity Installation of the weather resistive barrier is inconsistent. At areas where water infiltrates or exists behind or under the cladding, rot and other damage exist in the substrate and framing. Cladding penetrations lack protective flashings. S:\B Leschi House\Report\B Leschi House Report mvh.doc page 2 of 4

3 RDH Building Sciences Inc. Stucco The existing stucco was reportedly coated with an elastomeric coating. We do not have any information regarding the nature of this coating. Additional coatings are not recommended at this time as the addition of even a vapor permeable elastomeric coating may unfavorably alter the performance of the walls. While coatings are an effective means of limiting stucco water absorption into the cladding, they can adversely affect the ability of the wall assembly to dry. RDH recommends coordinating cladding replacement with the window replacement, utilizing rainscreen cladding assemblies. Considering the damage that exists in many stucco clad areas, evidence of water infiltration behind the stucco exists and the current condition can only worsen over time. Because proper window replacement requires removal of 4 to 6 inches of stucco surrounding each window, the inherent difficulty of re-installing effective long-term detailing to prevent moisture intrusion, and the probable lack of installer warranty, complete stucco replacement is recommended at the time of window replacement. Windows Windows are 21 years old and nearing the end of their anticipated effective useful life of 20 to 25 years. Windows tested operated smoothly. Ten sill dam tests were conducted and six windows leaked. In addition to windows that leaked when tested, during our site observations residents reported active leaks in six windows. Residents also report drafts from the windows and numerous insulating glass units are fogged. Signs of window leaks exist in several unit interiors. Complete window replacement is recommended in the near term. Condition Assessment Limitations and Basis of Cost Opinions We endeavored to access the current condition of concealed elements by means of selective destructive investigation at locations known to be problematic based on our experience or at areas of the building known to be experiencing problems. Thus, our site reviews are limited to what we directly observe or measure, and that which we can reasonably extrapolate to the rest of the building based on the type, frequency and severity of problems found and our experience investigation hundreds of similar structures. The figures included in the opinion of costs should only be considered as budgetary figures, and could substantially increase or decrease depending on factors outside our observations. The conceptual cost opinions and recommendations provided herein are based on our experience and unit price discussions with contractors specializing in restoration and repair work. The costs include labor and material, general conditions, design fees, overhead and profit, but not taxes that may be assessed. No bids were obtained, and no drawings prepared. Cost opinions include removing and disposing of the original cladding materials, windows and doors. The contractors consulted have not visited the buildings. Accurate costs will require further investigation and preparation of detailed contract documents. Closure S:\B Leschi House\Report\B Leschi House Report mvh.doc page 3 of 4

4 RDH Building Sciences Inc. We trust the information contained herein will be useful in helping to establish work and budget priorities for the properties considered. If you have any questions, comments or concerns, please do not hesitate to contact the writers. Yours truly, RDH Building Sciences Inc. Michael Aoki-Kramer Building Science Specialist Mark V. Hillman, Architect Building Science Specialist S:\B Leschi House\Report\B Leschi House Report mvh.doc page 4 of 4

5 Leschi House Report Photos Photo 1 Photo 2 Photo 3 Photo 4 Photo 5 Photo 6 1 of 3

6 Leschi House Report Photos Photo 7 Photo 8 Photo 9 Photo 10 Photo 11 Photo 12 2 of 3

7 Leschi House Report Photos Photo 13 Photo 14 Photo 15 Photo 16 Photo 17 3 of 3