Mass-produced, hurricane-resistant homes become reality

Recent damage caused by Hurricane Irene and Tropical Storm Lee has shown the importance of implementing newer solutions when building coastal homes. The idea of mass-producing hurricane- and storm-surge-resistant homes is not new, but until now it has been a difficult concept to accomplish. However, ForeverHome believes it has the solution.

ForeverHome, a partnership between Spancrete, Steve Berkus of Berkus Construction, Mathias Reymann of Ratec LLC, and EPIC Creative, is based on the concept that concrete is the optimum solution for providing durable, dependable housing in hurricane-prone regions. A 170-mph (3-second) gust is the design wind speed for the ForeverHome structural calculations. With the factor of safety, the structural shell of the home can withstand winds in excess of 200 mph. Furthermore, by using a patented system, homes are affordable—starting at $170,000—with each model including finished interiors. There are currently six base floor plans, each one offering three elevation options, for a total of 18 models. Each standard model can be raised to meet the base flood elevation criteria established by FEMA and the Institute for Business and Home Safety (IBHS).

The homes are system built with base facilities in Wisconsin, Florida, Atlanta and Chicago. Joe Rogge, spokesperson for ForeverHome, explains, “With increased volume, we could have the ability to produce in proximity to development locations. Our flexible, patent-pending fabrication process allows for mobility in our manufacturing procedure. When higher demand is warranted, we will also evaluate additional base facilities.”

Individual Components
The structural shells of the homes are completely made of reinforced precast elements. Connections between the components are designed with reinforcing steel and high-strength cement grout. Moreover, the configuration of the pieces and the way they are connected allow for quick and efficient construction.

The roof’s individual sections are gable-shaped and have ribs that provide the flexural strength required to span the entire width of the structure. It has a continuous 5-in. layer of rigid insulation cast within the concrete. The concrete surface can be cast with various form liners to yield a profile appropriate for the architectural style of the home. Integral gutters are cast into the roof sections and assist in controlling and diverting rain water. Furthermore, the joints between roof members are sealed to prevent water intrusion, and an additional membrane is applied over the entire surface of the roof, further waterproofing the structure.

The precast walls provide strength for both applied gravity forces and horizontal forces. Two layers of reinforced concrete are separated by 3 in. of continuous rigid insulation. The exterior surface has architectural features cast into the concrete using interchangeable form liners. Also, the concrete form liners can replicate common building material, such as lap siding or brick masonry. Andersen Window Corp.’s Stormwatch Series of high-impact, hurricane-resistant windows and doors are installed in-plant and once the home is erected onsite, the shell can be locked and secure.

The floors are made of Spancrete’s Hollowcore prestressed concrete plank. It has a standard width of 4 or 8 ft. and comes in thicknesses between 6 and 16 in. The planks are designed and cut specific to a location on the structure. Each plank has a specially shaped edge and when planks are set adjacent to each other, the void between them is grouted. This process facilitates load sharing between members.

The Hollowcore bears on L-shaped reinforced concrete beams around the perimeter of the structure. These beams also support the weight of the wall and roof. If a porch or deck is specified, these beams can cantilever over the columns to create the space using the Hollowcore as the floor surface. Thus, adding a front or rear porch results in a larger building footprint with no increase in foundation size.

Also, entrance stairs to the elevated structure are made of precast to ensure strength and durability. The stair steps are cast integrally with the upper landing and are supported by the concrete foundation.

AQPrototype Model
Currently, ForeverHome has only completed one home, their prototype model in Sebring, Fla. Spancrete’s Joe Rogge notes that the prototype has exceeded expectations and has been certified LEED Platinum. This has allowed for pre-certification of newly built ForeverHome models as LEED Silver. The prototype also exceeds the flood- and wind-load specifications designated in FEMA 550 for Recommended Residential Constructions for the Golf Coast. It also meets ASCE 7-02 minimum design loads for buildings and other structures.