Basements
A growing number of the manufactured homes being sited in Minnesota are being placed on basements. We are also noting that a number of manufacturers drawings are not indicating a method of connecting the manufactured home to the foundation that will provide a lateral restraint to the top of the basement wall. Both the Uniform Building Code and One and Two Family Dwelling Codes require that each joist be nailed to the sill plate with three (3) 8d nails. The nailing, along with the 1/2" anchor bolts 6' oc. grouted in the masonry or concrete wall allows the soil pressures applied against the basement wall to be resisted by the floor diaphragm. All manufacturers are to submit to our office their method of providing this lateral restraint to the foundation wall. If the installation method does not allow the nailing or the use of mechanical fasteners in attaching the floor joists directly to the sill of the basement wall at a maximum of 24" oc an engineers design must be submitted. Dealers and installers if you are selling or installing a home on a basement or crawl space and you are not attaching the home to the foundation to provide the lateral restraint to the top of the wall and providing resistance for wind movement you are in violation of the Minnesota State Building Code. The HUD Standards do not address basement construction. If the manufacturer chooses not to provide this information the only other recourse in placing their home on a basement is to have a Minnesota Licensed Engineer design a foundation as a retaining wall so all the soil pressures are resisted by the basement wall and footing. A number of dealers are using wood foundation systems as a basement. The nailing and/or the use of mechanical fasteners in attaching floor joists to the top plate of the wood foundation wall is very critical, make sure that the system is adhered to in its entirety.
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