FLOOD02929 - Laserfiche WebLink

Home Browse Search

CHAPTER V ECONOMICS Costs associated with developing a site and elevating a manufactured home on the site are important factors in selecting an elevation strategy. These costs consist of those necessary to improve the site, erect the elevated foundation design developed pursuant to Chapter IV, and properly secure the manufactured home on that foundation. This chapter presents a format and guidance for estimating the first costs associated with those site design options found acceptable from a technical standpoint. Cost ranges are provided with which a general estimate for a particular design can be developed. Due to the number of possible siting and flood situations, it is difficult to provide specific cost data on each particular design option. Moreover, the variance in labor rates, distance to the site, cost of materials, etc., further highlight the difficulty in developing and stating a firm fixed cost for each elevation technique. In evaluating the economic aspects of an elevated manufactured home installation, the cost of a conventional installation must be recognized. This establishes a baseline cost with which additional improvement and elevation costs can be compared. The additional costs associated with improving the site and elevating the manufactured home (i.e., fill, elevation, anchoring, etc.) can then be considered in relation to the cost of a conventional installation. CQl'!v~ntiOl"!al Installations As discussed in Chapter I, a conventional installation (without consideration of flooding) consists of piers on which the manufactured home rests and ground anchors to secure the manufactured home on top of the piers. The piers will generally be two feet in height and located under the manufactured home in accordance with the manufacturer's instailation instructions. In addition, ground anchors will generally be installed every 10 feet along the length of the manufactured home. The cost for a conventional installation two feet to the bottom of chassis I-beam will generally be as follows: Cast-in place concrete piers Built-up unreinforced masonry piers $100-$150/pier $ 50-$100/pier Jacking and placement Ground anchors and tie downs $200-$300/section $ 35-$75/anchor Conventional installation costs, not including miscellaneous clearing, grading work, steps, utility connections, etc., are shown for various length single section manufactured homes in Table 5.1. For various len'gth double section manufactured homes, conventional installation costs are shown in Table 5.2. As previously discussed, these cost ranges may not represent local conditions, labor and material rates, as well as conventional installations which may not utilize piers and ground anchors. Using these costs as a baseline, the following costs for fill and additional elevation through piers, posts, and piles can be placed in perspective. It is important to note that, in general, as the height above grade increases, the incremental cost for each additional foot of elevation decreases. This can be largely attributed to labor and other fixed costs which are essentially the same regardless of height. Therefore, additional elevation will provide a relatively low cost safety factor against unusually high flooding. Earth Fill Earth fill can be used to elevate a manufactured home in areas where flood velocity is not greater than 10 fps. Prices for any site work vary considerably due to the present condition of and need to clear the site, distance from sources of fill, quality of fill, and costs of the fill material. The cost for earth fill material will generally range from $2.00 to $4.00 per cubic yard, not including any additional site work required. In some cases, the total cost of elevating with fill may be as much as $10.00 to $12.00 per cubic yard. For instance, the Residential Cost Handbook by Marshall and Swift show costs from $2.43 to $3.78 for soft earth and $3.51 to $5.94 per cubic yard of fill for hard earth. If earth fill is considered for use in elevating a manufactured home local excavating and hauling contractors should be contacted for an accurate estimate. Based on a cost of $2.00 to $4.00 per cubic yard of earth fill, the ranges in Table 5.3 are shown for various length single and double section manufactured homes. 71