My question concerns the initial installation of a whole house fan. Does the fan need a center joist to support it? If so, will I be able to adequately block in a center brace (not using a ceiling joist) to install my fan? If you're wondering why I need to do this, my house is very small and the only place I can put it to supply adequate circulation will not allow me to have center support. Please respond asap as it's hot and I need the fan!