HomeMy WebLinkAboutFile Documents.230 E Hopkins Ave.0046-2020-BCHO (6)
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LETTER
9 June 2020
Sophie Varga, Zoning Enforcement Officer
City of Aspen
Community Development
130 S. Galena St.
Aspen, Colorado 81611
RE: 230 E. Hopkins Ave, Aspen CO 81611 Setback Encroachment for additional 5/8” type X
GWB
Dear Sophie,
Rowland+Broughton is seeking an exemption to the 5’-0” building setback for a portion of the property
currently under construction at 230 E. Hopkins Ave. Below you will find a summation of this item and
why the exemption is necessary to maintain the appropriate fire ratings and ensure the life safety of
both the occupants of this building and the neighboring property.
Background information:
1. During the design process it was determined that the existing Mountain Forge building was
constructed partially over the property line to the west.
2. With the agreement of the neighbors, a lot line adjustment was made to modify the western
property line such that it moved west on the south side of the lot to accommodate the existing
Mountain Forge Building, and jogs East in the northern portion of the property to give the
same area back to the neighboring property. See Exhibit 1 (Survey).
3. North of the property line jog the existing wall framing and exterior sheathing will remain in
place. Due to the lot line adjustment the portion of the existing building identified in Exhibit 2
is now an existing non-conformity relative to the 5’-0” side yard setback requirement.
4. Per Table 602 of the 2015 IBC, Fire-resistance rating requirements for exterior walls based on
fire separation distance, a 1-hour fire resistance rating is required for any portion of the
building that is within 5’-0” of the adjacent property line. See Exhibit 3 (Table 602).
5. 2015 IECC Insulation requirements at exterior walls require R-20 cavity + R3.8 continuous
exterior insulation. See Exhibit 4 (2015 IECC Table C402.1.3)
Proposed Solution:
1. We are proposing adding an additional layer of 5/8” Type X glass matt sheathing in between
the existing exterior plywood sheathing and new exterior wood siding (replacing the existing
exterior wood siding). See Exhibit 5 (W8(F)SIM assembly detail). This solution would require
an exemption to the zoning setback requirement to allow the additional 5/8” additional
encroachment beyond the existing non-conformity.
2. In Lieu of increasing the existing setback non-conformity beyond the required 5/8” for item 1
above, we are proposing over insulating the cavity to R-39 at this location and omitting the
continuous exterior insulation component of the IECC requirements at this location only. This
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will require a Building Department Exemption from the prescriptive IECC requirements for the
area of concern.
Our intent with this proposal is to minimize additional setback encroachment beyond the existing non-
conformity while providing appropriate fire resistance ratings required by current building code. We
believe that this proposal meets the intent of all applicable building and zoning regulations while
limiting any non-conformities.
Please be in touch with any questions or concerns.
Respectfully submitted,
Jonathan Rice
Architectural Designer
rowland+broughton
970.544.9006 studio
970.429.8763 direct
Dana Ellis
AIA / NCARB / LEED AP / Studio Leader
rowland+broughton
970.544.9006 studio
203.610.7633 cell
08/06/2020