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120106-Dewey - Code Summary for InspectorPage 1 of 8 January 6, 2012 Project and Code Summary and Structural Review for Building Inspector Review Renovations and Repairs to Dewey House 4 Neilson Drive Smith College Northampton, Massachusetts Prepared by: Laura Fitch, AIA, LEED AP BD&C Kraus-Fitch Architects, Inc. 110 Pulpit Hill Rd. Amherst, MA 01002 413-549-5799 lfitch@krausfitch.com Background – Dewey House: Original Construction: 1827 Style: Greek Revival; Architect Ithiel Town Early History: Named for Judge Charles Dewey, one of Northampton’s distinguished citizens whose heirs sold it and much of the original Smith College campus to the newly established college in 1871. In 1875 it housed the entire college of “fourteen young ladies” who were Smith’s first students. History of Changes: The building was moved twice. It was moved in 1898 to its present site when the ell was added to make room for more students. At some point the attic level of the original building was occupied as a dormitory. Apparently chords of the original heavy timber roof trusses were removed for this purpose and may have been the cause of some of the severe deformity of the building. In 1994, diagonal chords were reintroduced to these trusses under the direction of Brennan & Partners, Inc. Presumably the attic level was abandoned at this time. Many holes were cut in the plaster ceiling to do this and other structural repairs. They were never patched and are a direct conduit for warm air to get under the roof sheathing. This is an extreme energy by-pass and is likely to be cause of ice-damming. Modifications for handicap access (new ramp and porch on south and accessible toilet room) and modernization of the first floor back wing were made in 1994. Historic Building, Districts, Etc. Dewey House is located almost entirely outside of the Elm Street Historic District. However, Wayne M. Feiden, Director of Planning and Development for the City of Northampton pointed out that the north east corner of the building is within the district (see maps in Appendix A) and stated in an email Page 2 correspondence “the boundary is exact, so if you are doing work on that northerly corner, you need a permit from Elm Street, and otherwise you don't”. Size of Building Footprint with porch (exterior) = approximately 4,689 SF Total Finish Interior Square footage = approximately 8,289 SF • 3,493 first floor (interior) • 3,276 second floor (interior) • 1,520 third floor (interior) Basement (relatively unfinished space, not currently occupied) = approximately 3,275 SF Assessed Value of Building $2,949,477 insurance carrier’s building valuation (Dec. 2011) $1,037,630 (from City of Northampton, Commercial Property Parcel 31D-008-001 Card 2) $2,486,720 = value of land, however this parcel is shared with 4 other buildings. Code Summary The purpose of this code analysis is to determine the extent to which the existing Dewey House will need to be brought up to various codes. The starting assumption is that basic building envelop, bathroom, and finish improvements are needed. Additional items may be triggered by this level of work, and have been investigated below. Any structural assessment is preliminary. There have been many structural modifications over the years. The majority of the original structure and the modifications are hidden from view. Further assessment will be required as demolition and reconstruction begins. This study is not all-inclusive. It is based on educated assumptions regarding existing conditions. Indication of “code compliance” within this study does not represent a guarantee on the part of the architect that the existing conditions meet all aspects of the code, but rather that they appear to meet the critical life safety aspects of relevance to the proposed use and modifications. It should also be noted that THREE NEW codes have been reviewed for this report and that the building commissioner of the City of Northampton has indicated that many aspects of the code are not yet fully understood by the state code officials. The interpretations by Kraus-Fitch Architects (KFA) does not guarantee similar interpretations by officials now or at a future date. Referenced Codes and Other Sources The original building was built prior to any modern codes. The following review is based on the following codes: • 2009 International Building Code (IBC) • 2009 International Existing Buildings Code (IEBC) • 2009 International Energy Conservation Code (IECC) • Massachusetts Amendments to the IBC 2009 • Massachusetts Architectural Access Board Regulations • Northampton Code of Ordinances – Chapter 195 Historic Districts • Elm Street Design Standards and Boundary Map Page 3 • “Asbestos Inspection, PCB Inspection and Lead Based Paint (LBP) Determination Report” dated June 1, 2011 conducted by ACT Assocates, Inc. Existing and Proposed Uses Use Group B: Educational occupancies for students above the 12th grade, Accessory Assembly spaces meet definition for B use (< 750 SF) Existing Building Code (IEBC) Compliance Method: 101.5.1 Prescriptive: comply with Chapter Classification of Work (Chapter 3): Note: See the Detailed Code Analysis for more detailed information, specifically regarding Chapter 3.. • Compliance Alternatives: No compliance alternatives are requested at this time, but should be considered if needed. Construction Type VB (5B) Combustible, Unprotected Note: Construction may actually be VA (5A) Combustible, protected – more examination of the archaic Construction would be needed to determine this. Area / Height Limitations Use Group B with Type VB Construction allows for 2 stories, 9,000 SF per floor Existing building is 3 stories with 4,690 SF footprint (including ramp and porch), the existing building has a sprinkler system (which presumably meets 903.3.1.1) allowing for height increase of 1 story - appears to comply Egress Occupancy Load: • Basement Level: o 3,275 SF / 300 11 occupants • Main Level: 138 occupants o Accessory Assembly Room A: 575 SF / 7 82 occupants o Accessory Assembly Room B: 290 SF / 7 42 occupants o Office / Lounge: 1,350 SF / 100 14 occupants • 2nd floor: o Offices: 2,034 SF / 100 21 occupants • 3rd floor: o Offices: 1,073 SF / 100 11 occupants Number of Exits and Vertical Means of Egress: There are two means of Egress from each Level. • Basement: There are two (2) exits, one (1) into a fully enclosed fire stair which exits directly to the exterior, one (1) into an enclosed stair which leads to the Front Hall which has an exit directly to the exterior – complies for existing buildings • Main Level: There are two (2) exits directly from corridors to exterior. There is a third exit through adjoining spaces into the stair tower and out to exterior - complies for existing buildings • Second Floor: There are two (2) exits, one (1) into a fully enclosed fire stair which exits directly to the exterior, one (1) into a semi-enclosed historic curved stair. The latter is enclosed at the top with a glazed partition and door. The stair leads to the Front Hall which has an exit directly to the exterior – complies for existing buildings Page 4 • Third Floor: There are two (2) exits, one (1) into fully enclosed fire stair which exits directly to the exterior, one (1) into a semi-enclosed historic L-shaped stair. The latter is enclosed at the top and bottom (with closers on magnetic hold opens at the 2nd floor level). From the second floor level egress is into egress access corridors to the two stairs listed above – complies for existing buildings Egress Width: All egress components are of sufficient width for the occupant load and use with the possible exception of the basement interior stair and the third floor interior stair. – complies for existing building. If the stair to the third floor is replaced it may need to be widened although existing building code does allow for exceptions if there is not sufficient space (303.1 exception 1). Other Egress Items • Exit Access: All exit access appears to be sufficient in width and configuration. • Exit signs: Appear to be sufficient in number and location. These will however be modernized. • Means of Egress Illumination: There are emergency lights in halls and stairs. These will however be modernized. • Accessible Means of Egress: is NOT required for alterations to existing buildings, nor is it required by AAB code. Fire Separation Assemblies • Stairs: o Stair tower (basement to 3rd floor) – fully separated, complies o Interior basement stair – fully enclosed, presumably with rating, sufficient for existing building. o 1st – 2nd stair – existing smoke partition at top appears sufficient for existing building. o 2nd – 3rd stair – enclosed (doors have magnetic hold opens) but with some office doors opening into it; some modifications to the enclosure may need to be made if stair is rebuilt. • Incidental Uses o Furnace and boiler rooms: not applicable (fed by steam lines from external power plant) • Corridor Separation: not required for B use. • Floor Ceiling Assemblies (basement ceiling): none required for VB building type with B use except as noted above for incidental uses. Fire Protection Systems: The architectural review of this section is for feasibility study only; a full Chapter 9 narrative is likely to be required at time of permitting. • Sprinklers: The building is equipped throughout (including attic) with a dry pipe fire suppression (sprinkler) system. It will be modified as needed to accommodate minor floor plan changes. • Portable Fire Extinguishers: Fire extinguishers were noted on site and are presumably functioning and sufficient. • Manual Fire Alarm Boxes: Pull stations appear to be located at every exit. These are presumably function and sufficient. • Visual and Audible Alarms and panel: These are noted for replacement as part of this project. • Carbon Monoxide Detection: not required for this building type. Page 5 Plumbing The plumbing piping and fixtures are to be replaced throughout the building and will be code compliant. There is no change of use so full compliance with the code for total number of fixtures and their location is not required at this time. There are however sufficient number of toilets. There are custodial closets with sinks on first and second floor. Drinking fountains will be added at first and second floors (2 total). Energy Conservation: Only changes (Additions, alterations, renovation or repairs) to the building envelop (including replacement windows) and mechanical and electrical systems are required to comply to the IECC at this time. Although not required, work will include extensive air sealing and insulation of attic and exterior walls. Handicap Access: The proposed work amounts to far greater than 30% of the full and fair cash value of the building and therefore the full building must be brought into compliance with 521 CMR. However, the building is “eligible for listing in the National or State Register of Historic Places” (and is partially within the elm street historic district) which qualifies the building for “alternative accessibility. (Letter of Determination is in Process – Jan 2012) A critical decision was made by the owner to apply for a variance for elevator access to third floor. With only 6 offices at the third floor level and an elevator tower that would otherwise have to extend above the historic eave line, the latter seems reasonable and is recommended. (Application will be started immediately upon receipt of Letter of Determination) The following sections are of particular relevance, although there may be some other minor items that would need changes. 26 Doors: First floor should be made to fully comply. Variances for upper level doors are recommended. • Width: 32” clear - first floor door widths comply, all upper level doors do not and should be made to comply unless variances are sought. • Clearances – most of first floor doors comply (with exception at Rm. 102 which has alternative access through adjoining room), many upper level doors cannot be made to comply without moving partitions (variance should be sought) • Hardware – Only doors off the back hall on first floor comply, all hardware should be replaced even if door widths and clearances do not comply 27 Stairs • The new egress stair: presumably complies. • Curved Historic Stair: complies for nosings, needs a second handrail • Stair from 2nd to 3rd floor: This stair is scheduled to be replaced. It may not be possible to fit code compliant stair in current location. Variances might be required. 28 Elevators: An elevator is required for this building for this level of work. It is technically required to serve all public levels, but it is recommended by the architect that elevator access be limited to the first and second floors. A lift is not allowed for a three story building, but is likely to be allowed by variance if limiting to second floor. 30 Public Toilet Room: presumably the first floor toilet room complies, the second floor toilets should be made to comply, and a variance should be sought for the third floor (regardless of elevator access). 32 Kitchens: The second floor kitchenette does not comply for clearance at sink Page 6 34 Storage: The first floor copy room appears to comply. The upper floor office closets appear to comply for side reach. 39 Controls – shall comply 40 Alarms: if emergency warning systems are provided, then they shall include both audible and visual alarms – shall comply 41 Signage – shall comply Structural Review Ryan Hellwig, PE made the following report based on the 1994 structural drawings, section drawings, and measurements taken on site. 1. Scope of Work - Structural improvements a. Further structural analysis of existing roof structure is required. Reinforcing of Purlins in both sections will be required. Reinforcing of the trusses may be required. b. During the renovations of the bathrooms, some water damage may be discovered due to leaks or previous cutting for piping. Reinforcement of existing floor joists in these situations may be necessary. 2. Code Review – IEBC Chapter 3 - Prescriptive Compliance Method a. Section 303 - Alterations (1) 303.3 Existing structural elements carrying gravity load. "Any existing gravity load- carrying structural element for which an alteration causes an increase in design gravity load of more than 5 percent shall be strengthened...as needed to carry the increased gravity load required by (the) code for new structures." The increase in design snow load will be more than 5% for this project, so analysis of the roof will be required, and some reinforcement may be necessary. No increase in floor live load is anticipated in this project. (2) 303.4 Existing structural elements carrying lateral load. (a) Exception: "Any existing lateral load-carrying structural elements whose demand-capacity ratio with the alteration considered is no more than 10 percent greater that its demand-capacity ratio with the alteration ignored shall be permitted to remain unaltered." There will be no increase in the lateral load demand-capacity ratios, so this exception applies to this project. The original building is over 175 years old. Over the course of its life, it has been modified many times, including having been moved twice. No complete, accurate structural drawings are known to exist. Sagging is noticeable in some locations, particularly of the old wing. Given the age and history of the building, such deformations are to be expected. In the 1994 renovation, some repairs were made to the existing structure, including restoring diagonal timbers and wooden pegs in the roof trusses, and reinforcing some rafters in the old wing, and installing some additional floor beams, columns and footings in the new wing. The drawings for that work call for structural loads per the 5th edition Massachusetts State Building Code. It is presumed that the repairs were made in accordance with those loads. However, the snow load in that edition was only 35 psf. The Page 7 current, 8th edition requires a 42 psf snow load for the area of Northampton when the roof is well insulated, which is a 20% increase to 35 psf. The floor live loads in the 5th and 8th editions are the same. Rafters: The rafters in the older wing are 3x7 spaced at about two foot centers, and in the newer wing the 1994 drawings show them as 2x9 at 20 inch centers. Rafters in both older and newer wings are adequate for current snow loads, assuming that they are in good condition - no rot, excessive checking, out-of-grade knots, or similar damage or strength-reducing defects.. Note: The sizing of rafters and purlins in the newer wing are shown on the 1994 drawings but the actual conditions are not visible. Purlins: Purlins in both older and newer wings are NOT adequate for current snow loads. The purlins in the older wing are 8x8 running framing into the quarter point of each roof truss, and in the newer wing they are 6x10, according to the 1994 drawings. The purlins in both wings are not adequate for current snow loads. In the older wing, the rafters are flush with the purlins, being set in mortises, with joist hangers added in 1994 - so purlins cannot be easily sistered. Reinforcement on the sides would require cutting back the existing rafters, and would also conflict with the steel saddles that were added in 1994 (see photo). Reinforcement underneath would pose difficulties in connecting to the truss, since that is also a flush connection. The connection detail in the newer wing could not be observed at this time. The structural engineer has requested that openings be cut in the plaster at three locations. Note: See Field Report 12-21-11. Trusses: The timber truss in the older wing appears to have a smaller top chord than bottom chord: 7x7 versus 9x9. The 9x9 is OK, but the 7x7 would be overstressed with the new snow loads. Reinforcing truss chords is difficult in many ways, including tying the reinforcements together at the heel joint, where there is significant outward thrust at the connection between top and bottom chords. The profile and details of the trusses in the newer wing are not shown on the 1994 drawings, and also are not yet visible in the building. Again, the structural engineer has requested that openings be cut to assess this and other conditions in the newer wing. Note: See Field Report 12-21-11. Page 8 ! RYAN S. HELLWIG, PE ! STRUCTURAL ENGINEER ! January 4, 2012 Laura Fitch, AIA, LEED AP Kraus-Fitch Architects, Inc. 110 Pulpit Hill Rd. Amherst, MA 01002 lfitch@krausfitch.com Re:Feasibility Study for Renovations and Repairs Dewey House Smith College Northampton, Massachusetts The following is a report of my analysis based on the inspection and probes that were made 12/21/11. Please refer to my report of 12/22/11 for a description of the probes. The rafters in the newer wing are full-sized 2 x 8 (1f" x 8") spaced at 19" to 20" on center. The rafters bear on the exterior walls and two lines of 6x10 timber purlins. The purlins are spaced 7 feet apart, and span approximately 17 feet between the endwalls and two roof trusses. The trusses have a simple queen- rod profile, spanning clear across the building. A sketch of the truss and purlins is attached. Roof truss members are 8 x 12 timber chords and 1¼" diameter vertical iron rods. All wood is assumed to be Eastern Hemlock. The top chords support the ends of the purlins, and the bottom chords carry the 3 floor joists. The ends of the trusses appear to be mortised into timber posts in the exterior walls ofrd the building, although the specific details of the joint are obscured by the construction of the 3 floor. rd Looseness was observed in one of the nuts on the iron pins that clamp the truss heel near these joints. My preliminary stress analysis indicates that the rafters are adequate for snow loads, assuming that they are at least a #1 grade. The purlins are not able to support the same snow load as the rafters. The truss top chords are able to support the snow load. The bottom chord has a high level of stress, due primarily to the live loads on the 3 floor. The live load there has likely increased since the original construction.rd §308.1 of the IEBC allows for historic buildings to be exempted from the structural requirements of the balance of Chapter 3 (Prescriptive Compliance Method), subject to approval by the Building Inspector. Thus the College could avoid some, if not all, of the reinforcements proposed for the roof if the building qualifies for this exemption. This could apply to the trusses in both the new and old wings. Upgrading the older trusses will be relatively labor-intensive work. The dead and snow loads on the trusses could be reduced by replacing the slate roofs with standing seam metal. The complete scope of structural work should be determined in consideration of these options in the context of the overall project, as well as plans for future renovations of the building. Respectfully, Ryan S. Hellwig, PE Massachusetts Professional Engineer #37300 - STRUCTURAL ! 28 ALDRICH STREET ! NORTHAMPTON, MA 01060 ! ! VOICE 413-584-HLWG (4594) ! FAX 413-584-HLWFax (4593) !