MIAMI SHORES DEPARTMENT OF PLANNING & ZONING 10050 NE 2 nd Avenue Miami Shores FL 33037-2304 www.miamishoresvillage.com David A. Dacquisto AICP, Director Main Number: 305-795-2207 Fax Number: 305-756-8972 PLANNING BOARD HEARING Miami Shores Village Town Hall Council Chambers 10050 NE 2 nd Avenue Miami Shores Hearing Date April 24, 2014 Subject Residential Height Limitation and Construction in the SFHA Action Required Recommendation to Village Council on Zoning Code Amendments to Address Residential Height Limitation and Construction in the SFHA Based on the Planning Board s Review and Analysis. Staff Report David A. Dacquisto AICP, Director, Planning and Zoning Report Date April 9, 2014 Background Village Council Request The Village Council discussed issues that may arise around the current residential building height limitation as it applies within the special flood hazard area (SFHA) and requested that the Planning Board consider the issue and return a recommendation to the council: Council Meeting - October 1, 2013 A.DISCUSSION AND POSSIBLE ACTION REGARDING A REQUEST THAT THE PLANNING & ZONING BOARD REVIEW THE CURRENT BUILDING HEIGHT LIMITATIONS IN LIGHT OF NEW FEMA REGULATIONS WITHIN SPECIFIC FLOOD ZONE Mr. Benton provided background information regarding FEMA regulations and the fact that there are a number of properties along the Village s shoreline that will need to be in compliance with State and Federal regulations regarding elevation heights. Village Planning Director, David Dacquisto also spoke regarding FEMA and the Florida Building Code building elevation requirements and gave examples of home designs and existing height limitations which should be reviewed. Councilman McCoy moved to send this matter to the Planning & Zoning Board for their review and recommendation report. Councilman Davis seconded the motion and the vote was unanimous in favor of the motion. Calculating Height The rules for construction in the SFHA are now stricter than they have been in the past due to actions by FEMA, and the State of Florida as a result of the incorporation of flood plain regulations into the Florida Building Code. One of the big changes was the introduction into the Florida Building Code of the requirement to elevate residences to the Base Flood Elevation (BFE) + 1 foot of free bore.
Construction in the SFHA requires 2 height calculations. First, the village calculates height to determine compliance with the 30 ft. height limitation for dwellings in the R districts. The starting point in calculating building height is to determine the base building level. From there you determine building height. Building level. The street grade or an elevation of five and one-half feet above mean sea level, whichever is the higher. Building height. The vertical distance from the building level (a) to the top of the roof in the case of flat roofs, or (b) to the mean level between the eaves and the highest point of the roof in the case of roofs of any other type. Second, the village must recalculate height based on different criteria to determine compliance with FEMA requirements. FEMA measures from 0 NGVD (sea level) to the underside of the lowest horizontal structural member in the VE zone and to the finished first floor elevation in the AE zones. Structures in the AE10 zone must be constructed so that the finished first floor is elevated to not less than BFE 10 + 1 foot resulting in a finished first floor elevation of not less than BFE 10 ft. + 1 ft. = 11 ft. National Geodetic Vertical Datum (NGVD). Starting from a ground elevation of approximately 5 ft. (NGVD), you would have to elevate the house to create a space of approximately 4 ft. under the residence (plus width of horizontal structural member and floor approx. 2 ft.) in order to elevate the finished first floor to 11 ft. NGVD (10 ft. NGVD + 1 ft.). Similarly, the first floor of structures in the AE 9 or AE 8 must be elevated to BFE 9 + 1 and BFE 8 + 1. Unlike the VE 11 zone, fill or solid wall foundations may be used to elevate residences in the AE zones. Diagram #1 Structures in the VE11 zones must be constructed so that the bottom of the lowest horizontal structural member of a building is elevated to not less than BFE + 1 foot resulting in the elevation of the bottom of the lowest horizontal structural member to not less than BFE 11 ft. + 1 ft. = 12 ft. National Geodetic Vertical Datum (NGVD). The ground elevation on the VE 11 example is approximately 4 ft. (NGVD). You would have to elevate the house to create a clear space of approximately 8 ft. under the residence in order to elevate the lowest horizontal structural member to not less than 12 ft. NGVD. Diagram #2 A one-story residence may be constructed on pilings in the VE zone and meet the code requirements. A two-story residence may be constructed on pilings in the VE zone and meet the code requirements however, the design is important: Four (4) design considerations: Creating usable space under a two-story residence may require greater clearance under the residence and will increases the height of the dwelling. Ceiling height is an important factor in constructing a two-story residence as it increases the height of the dwelling. A peak roof on a two-story residence will increase the height of the dwelling. A flat room option in addition to a peak roof will give more design options. Page 2 of 12
Diagram #1 Page 3 of 12
Diagram #2 Page 4 of 12
Considerations Raising the height limit would provide more flexibility in raising the residence to create usable space underneath however the use of the ground level of the residence is greatly restricted by FEMA rules in the VE zone where solid walls are not permitted. Raising the height limit would potentially allow higher ceilings in two-story residences. Allowing flat roofs on residences will allow the house to be measured to the flat roof surface rather to the midpoint as we measure on a peak roof. This adds additional usable height that may be used for room height or usable space under the residence. A complicating factor is the DERM requirement that drain fields must be set back from surface water and separated from ground water. Under the new requirements of the Miami-Dade Department of Regulatory and Economic Resources, Environmental Plan Review Division (DRER, EPRD), 2 ft. of separation is required between the level of the ground water at the site and the bottom of the drain field. Added to this would be the height of the drain field and the soil layer above the drain field. This results in a septic system that may include a mound of 3 ft. or more in height depending on the ground water level and the design of the mound system. Another provision requires that any septic system be set back not less than 75 feet from water s edge. This plus the desire to fully develop the rear yard result in the construction of mound systems in the front yard. The side slope on a mound system at 3:1 will add to the width of a mound increasing the ground area necessary to place the system. Some additional rules from the State: (f) There shall be a minimum 4 feet separation between the shoulder of the fill and the nearest trench or absorption bed sidewall. Where a portion of the mound slope will be placed adjoining to building foundations, pilings or supports for elevated structures, mobile home walls, swimming pool walls, retaining walls, or similar obstructions there shall be a minimum 5 foot separation between the sidewall of the absorption area and the obstruction. Such obstructions shall impact the slope on no more than 50 percent of the shoulder perimeter. Retaining walls must be designed by a professional engineer licensed in the State of Florida to withstand the lateral earth forces under saturated conditions and to prevent seepage. A mound system will limit development on a site and will change the appearance of the residence from the street to some extent. Height Limitations The current height limit is 30 ft. for residences in Miami Shores. This allows many development options including two-story residences in the SFHA. It may not permit a specific plan that an individual wants to develop. Monroe County Raised homes are very common in Monroe County. The height limit there is 35 feet. Page 5 of 12
Key Biscayne In Key Biscayne the maximum height of a residence is 35 ft. if constructed at the front setback line. However, the building wall cannot exceed 22.5 ft. in height for a two-story building so ceilings height is limited to approximately 8-10 feet. The height of a Building shall be its overall height measured from the Base Flood Elevation to the highest point of the Building roof for Elevated Homes and from the crown of a road to the highest point of a roof for Non-Elevated Homes. Maximum number of stories shall not exceed two above the Base Flood Elevation. Vero Beach In Vero Beach the maximum height of a residence is 35 ft. Starting point for height measurements. The starting point for measurement of any building height shall be whichever is the highest elevation of the following: (1) The existing weighted average grade elevation of the property; (2) The base flood elevation; (3) The base flood elevation plus 18 inches, if located within a coastal high hazard area (V Zone); Miami Shores Applicability In all the above examples, the height of buildings is set for the entire city. In the last two examples, the height calculation is modified for the SFHA by utilizing the BFE as the starting point rather than grade or road height etc. A quirk in the regulation is that in the VE zone the BFE is set at the bottom of the lowest horizontal structural member and therefore the width of the lowest horizontal structural member is counted against the height while in the AE zones the BFE is set at the level of the first floor a difference of approximately 2 ft. depending on construction. To implement this policy it would be necessary to modify the definition of building level to eliminate or an elevation of five and one-half feet above mean sea level, whichever is the higher and to adopt a form of the above language from Key Biscayne and Vero Beach. In the case of Miami Shores, within the VE11 zone the village would have to calculate the height of a building along the bay from BFE 11 (NGVD). Starting at the current building level of 5.5 ft. (NGVD), the first 5.5 ft. in structural height above the building level would not count against the building height limit as this would take the residence to the BFE of 11. From there you would be allowed to construct a 30 ft. tall residence. This would result in an actual height measured from the current building level and based on the existing code, of 35.5 feet. This provision has the effect of applying a single height limit throughout the village while addressing the special case of residences in the SFHA that are subject to FEMA and Florida Building Code regulations. A side effect of this would allow a residence in a VE11 zone to have a greater overall height than a house in an AE 8 zone nearby although the residence in the AE8 Page 6 of 12
zone may have a greater interior room height because of the way height is measured in the VE vs. AE zones (see above) Effect of Building Height and Building Setbacks on Sight Lines The board asked staff to review the effect on sight lines of raising the height limit from 30 feet to 35 feet. In other words, how far back in the plot would you have to build a 35 ft. residence to give it the appearance as a 30 ft. tall residence that is built at the front setback line, 25 ft. from the front plot line? Calculating the angle of elevation for a 30 ft. tall building constructed 25 ft. from the front plot line and utilizing the same angle of elevation for a 35 ft. tall building, a 35 ft. tall building constructed 36 ft. from the front plot line will have the same sight line from the center of the road as the 30 ft. building constructed 25 ft. from the front plot line. Sight line Angle of elevation Analysis The board held numerous workshops, reviewed the information provided, discussed the issue, reviewed alternatives and considered the need for amendments to the zoning code. Five (5) Zoning Code alternatives were identified for further investigated by the board to address the height limitation in Miami Shores: 1. Take no action: a. The current code allows 1 and 2-story residences anywhere in Miami Shores. Compliance is a matter of balancing design considerations. 2. Amend the Zoning Code to allow 35 ft. residences anywhere in Miami Shores. a. This would provide for the equal application of height regulations throughout the community. b. The height of dwellings is not an issue in most of the community. Height limits for dwellings is only identified as an issue in the SFHA and especially within the VE zone adjoining Biscayne Bay. Page 7 of 12
3. Amend the Zoning Code to allow 35 ft. residences in the Special Flood Hazard Area: a. Provide for a 35 ft. maximum height in all SFHA. b. Provide for a 35 ft. maximum height in the SFHA, VE Zone only. c. Provide for a 35 ft. maximum height in the SFHA, VE Zone for properties adjoining Biscayne Bay. 4. Amend the Zoning Code to allow 35 ft. residences subject to increased front yard setback: a. Provide for a 35 ft. maximum height throughout the village subject to a 35 ft. front yard setback. b. Provide for a 35 ft. maximum height in all SFHA subject to a 35 ft. front yard setback. c. Provide for a 35 ft. maximum height in the SFHA, VE Zone only subject to a 35 ft. front yard setback. i. Based on VE designation. ii. Based on location adjoining Biscayne Bay. 5. Amend the Zoning Code to allow the second story to rise to 35 ft. if the second story is set back 35 ft. from the front plot line: a. Provide for a 35 ft. maximum height in the SFHA, VE Zone only subject to a 35 ft. front yard setback for the second story. i. Based on VE designation. ii. Based on location adjoining Biscayne Bay. Page 8 of 12
Page 9 of 12
Board Consideration 1. The board may determine that no action is necessary. Two-story residences may be constructed anywhere in Miami Shores under the 30 ft. building height limitation without changing the current zoning code language. The issue is one of architectural design rather than the zoning code. 2. The board may consider if there is a basis to treat one area of the village differently from another area of the village. The board may determine that the height issue is not one affecting the entire village and a blanket height increase is not warranted. Houses have been constructed under the 30 ft. building height limitation throughout the village. The board may further find that issues exist in the SFHA that do not exist in the rest of the village. Houses in the SFHA must be elevated to bring the residences out of the SFHA. Houses in the VE zone must be elevated the most placing the residences on pilings to allow storm surges to pass under the residences. 3. The board may determine that an increase in the maximum height of a residence to 35 ft. is warranted to offset the building restrictions within the SFHA. Within the SFHA the VE zone requires the lowest supporting member of the residence to be elevated to NGVD 12. Within the SFHA VE zone the most problematic plots area located adjoining to Biscayne Bay. There is sufficient room on plots located within the VE zone but not adjoining Biscayne Bay, to construct within the AE zone where buildings are not required to be constructed on pilings. 4. The board may determine that an increase in building height is warranted subject to an increase in building setback from the front plot line. Setting a 35 ft. tall building back 35 feet from the front plot will create the same sight line as a 30 ft. tall building set back at the current setback line of 25 feet. Recommendation The Planning Board make a recommendation to the Village Council on zoning code amendments to address residential height limitation and construction in the SFHA based on the Planning Board s review and analysis of the question and issues. Five amendment options are provided for the board s consideration, modifications or combinations may be warranted based on the Board consideration s noted above: Amendment Options #1 No Change. Page 10 of 12
#2 Blanket Height Increase. District Minimum Plot Size Reserved Maximum Building Height R-35 R-30 R-28 R-26 R-25 R-23 R-22.5 R-21 R-20 R-18.5 R-17.5 R-16.5 R-15.5 R-15 R-14.25 R-13 R-12.5 Width: 75 feet Area: 7,500 sq. ft. For dwellings: 2 stories, and shall not exceed 30 35 ft. in height. For other buildings: 40 ft., excepting, for all buildings, the features specified in Article V and subject to the conditions set forth therein. Accessory buildings: Not to exceed the height of the dwelling located on the same plot #3 Height increase in Specific Zones District Minimum Plot Size Reserved Maximum Building Height R-35 R-30 R-28 R-26 R-25 R-23 R-22.5 R-21 R-20 R-18.5 R-17.5 R-16.5 R-15.5 R-15 R-14.25 R-13 R-12.5 Width: 75 feet Area: 7,500 sq. ft. For dwellings: 2 stories, and shall not exceed 30 ft. in height with the following exception: For dwellings located in the Special Flood Hazard Area VE Zone Adjacent Biscayne Bay: 2 stories and shall not exceed 35 ft. in height. For other buildings: 40 ft., excepting, for all buildings, the features specified in Article V and subject to the conditions set forth therein. Accessory buildings: Not to exceed the height of the dwelling located on the same plot Page 11 of 12
#4 Limit Height Increase to Specific Area with Increased Front Yard Setback District Minimum Plot Size Reserved Maximum Building Height R-35 R-30 R-28 R-26 R-25 R-23 R-22.5 R-21 R-20 R-18.5 R-17.5 R-16.5 R-15.5 R-15 R-14.25 R-13 R-12.5 Width: 75 feet Area: 7,500 sq. ft. For dwellings: 2 stories, and shall not exceed 30 ft. in height with the following exception: For dwellings located in the SFHA, VE zone adjoining Biscayne Bay where a 35 ft. front yard setback is provided between the front plot line and the dwelling: 2 stories and shall not exceed 35 ft. in height. For other buildings: 40 ft., excepting, for all buildings, the features specified in Article V and subject to the conditions set forth therein. Accessory buildings: Not to exceed the height of the dwelling located on the same plot #5 Limit Height Increase to Specific Area Increasing Front Yard Setback for 2nd Story District Minimum Plot Size Reserved Maximum Building Height R-35 R-30 R-28 R-26 R-25 R-23 R-22.5 R-21 R-20 R-18.5 R-17.5 R-16.5 R-15.5 R-15 R-14.25 R-13 R-12.5 Width: 75 feet Area: 7,500 sq. ft. For dwellings: 2 stories, and shall not exceed 30 ft. in height with the following exception: For dwellings located in the Special Flood Hazard Area, VE Zone adjoining Biscayne Bay; 2 stories and 30 ft. in height or 35 ft. in height provided the second story of the dwelling or any portion of the structure over 20 ft. in height as measured from the building level, is set back not less than 35 ft. from the front plot line. For other buildings: 40 ft., excepting, for all buildings, the features specified in Article V and subject to the conditions set forth therein. Accessory buildings: Not to exceed the height of the dwelling located on the same plot Page 12 of 12