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HomeMy WebLinkAboutSUPPLEMENTAL INFO, Story Mansion Grant Application Memo.pdf Commission Memorandum REPORT TO: Honorable Mayor and City Commission FROM: James Goehrung, Director of Facility Services Chuck Winn, Assistant City Manager SUBJECT: Story Mansion Roof Repair and HB 645 Historic Preservation Grant for the Story Mansion MEETING DATE: November 9, 2009 AGENDA ITEM TYPE: Action Item RECOMMENDATION: Consider a motion Authorizing the City Manager to sign a House Bill 645 Historic Preservation Grant for Story Mansion BACKGROUND: When the details of House Bill 645 were announced the Friends of the Story Mansion met with staff and Comma-Q Architecture to review possible improvements for the mansion. Insulation of the building and replacement of the roof were recommendations that were made by the Architect. These recommendations would protect the building envelope, continue the renovation plan outlined in the building assessment, and preserve the historic character of the building. INSULATION There is very little insulation in the walls on the main level; none in the second and third story walls; and very little in the ceiling of the third floor. The lack of insulation means increased heating costs. The secondary impact from lack of insulation is ice damming on the roof which leads to roof leaks and premature deterioration of the roofing materials. The renovation of the basement and main level of the mansion have put the building back in use. All levels of the building are now heated with the new boiler system. Under occupancy, building temperatures will be increased on the main level and basement to around 68 degrees. The second and third levels will be kept at around 55 degrees to protect the interior finishes and protect the water from freezing in the heating system. Heat of course rises in the building. With the lack of insulation in the attic area the heat comes in direct contact with the underside of the roof. On a cold day the warm air rising from the building will condense on the underside of the roof. This can lead to deterioration of the roof sheathing and in some cases the accumulation of mold. During the winter when snow is present the heat melts the snow and the resulting water runs down the roof. When this water comes to the eve edge, the unheated areas of the roof soffit lead to the water refreezing. The frozen water forms an ice dam that holds back more water and the dam builds in size. ICE DAMMING The critical zone is the edge of the roof. The escaping heat keeps the run-off in a liquid state, the dam prevents the water from running off the roof. The result is roof leaks. Code requires a roof membrane 2 feet up the roof from where the walls of the building meet the roof to form a protective barrier at this juncture. The exterior renovations that were done with the EDI funds repaired some of the soffit and facia areas of the roof that were damaged by this freeze-thaw cycle. Since the repairs were completed, there is visible damage to the soffit on the north roof, which means the run-off is still a problem. It is possible that the insulation will address some, or all, of this problem. If the water damage continues despite the insulation, then the full cost of the roof replacement will fall on the city if the roof is not included in this grant request. ARCHITECTURAL ASSESSMENT OF THE MANSION When the City of Bozeman purchased the Story Mansion in April of 2003, one of the first actions taken was to commission an Architectural Assessment of the building. This assessment was completed in August of 2003. The items called out in the assessment have been used as a priority plan for all work done on the mansion. Previous work to date has addressed the items listed in the assessment as being in poor or failing condition. A review of the assessment reveals that the city has been quite successful in its efforts in that all of the identified improvements labeled as being in failed or poor condition have been remedied. In an effort to further stabilize the mansion we are now dealing with items that were categorized as being in fair condition in 2003. This progressive maintenance plan illustrates the active role the city is taking in preserving this recognized community asset. The question of waiting for the roof to totally fail before it is replaced, or being proactive and replacing the roof prior to failure as time and resources become available is one for consideration this evening. CURRENT ROOF The condition of the roof in the assessment is listed as fair, with some shingle cupping occurring. According to the assessment, the cedar shake roof was installed in1983. From this report the age of the roof is 25 to 26 years. According to the contractor office at a local lumber yard, 25 to 30 years is the accepted life of this type of roof. The lumber yard representative also said that once the cupping occurs that is a good sign that roof problems are starting to develop. When the cedar shakes were installed the amount of material left to the weather, the reveal, was increased. This is a fairly common cost cutting method. If an extra inch is exposed on each course of shingles the total area of roof covered is increased with fewer shakes. The extra shake exposure and the lack of insulation on the building are the likely reasons that the roof is showing the signs of deterioration that we are now seeing. When wood stays wet for long periods of time, it causes rot and then cracking when it dries out. Replacing the roof at this time would be a proactive measure. We can wait until the roof fails more over the main living areas of the building. Additional water damage would deteriorate the roofing materials and the insulation that we plan to install. Delaying the repairs until obvious leaking and roof failure usually mean deterioration of the roof decking, something that cannot be determined until areas of the roof are stripped. Waiting for the failure would also mean that we could lose our weather window of planning for the replacement at the best time of the year for roofing. Not having to initiate emergency repairs at an inopportune time would result in less cost and a better overall product. SHINGLES VERSES SHAKES When the roof was redone in 1983, the existing cedar shingles were replaced with cedar shakes. In addition to being installed with a wider reveal, the shakes are not as substantial as the shingles and are not in keeping with the historic character of the building. The replacement of the shakes with the more appropriate shingles would be within the historic guidelines this grant is intending to address. Shingles would have less reveal and are less prone to cupping than shakes. The new shingled roof will be placed with the recommended reveal. This project is one that can be quickly initiated once we get quotes from qualified contractors. It will also meet the criteria of the grant in that it will re-establish the historic character of the building with the shingle roof. A new roof will also assure a long-term preservation plan for the building because it will secure the envelope of the building. ROOF REPLACEMENT During the time that the property was vacant heat was kept to a minimum so that just the interior finishes were protected. Staff has been monitoring the roof and it is obvious from just the two or three snow event we have had this year that there is a good deal of snow melt off now that the building is kept at occupancy temperatures. More shakes are showing weather damage on the south and west sides of the building. No obvious leaks have been detected on the area of the roof over the building footprint. Because no additional renovations have occurred on the 3rd floor, a leak would not jeopardize any new remodeling of the lower levels. Should renovation work progress on the 2nd and 3rd floors, a sound roof structure would become even more important. A new roof would need to be added to the cost of renovation so that the added improvements would not be subject to damage. There has already been discussion about the use of the upper floors and the need to find a use that will be able to cover the costs of renovation. By taking care of the costs of the roof at this time, the renovation costs for the upper floors will not need to include roofing costs. Utilizing this source of funds would provide an opportunity to replace the roof prior to full roof failure. When options for the next round of improvements for the mansion were discussed, the criteria were projects that would meet the grant criteria add value to the building, and improve or not change in a negative way the future uses of the building. Based on what we now know about the condition of the roof, based on the research conducted for this grant, the roof will be placed on the Capital Improvements Budget, to be replaced by city funds prior to the expiration of the 30 year life of the roof. As the use of the building evolves from unoccupied to occupied, more use of the mansion means different maintenance practices for the building. The estimated timeline for the tear-off and replacement is 90 days. Some activities can continue in the mansion during this time, but scheduling will need to be considered as this project is scheduled. FISCAL EFFECTS: Should the roof not be included in the grant application or should the roof not be funded under HB645, the costs for the repair of the roof would need to be covered from other sources of funding depending on the roof deterioration manifests itself. The cost estimates shown on the attached preliminary project scope summary prepared by Comma-Q in July of 2009, lists the roofing costs at $141,508.00. ALTERNATIVES: As suggested by the City Commission. Attachments: Preliminary Scope Summary from Comma-Q Architecture Report compiled on: November 9, 2009