Foundation 4 and 5 both dropped support for IE8, and for a lot of projects, you can get away with not supporting IE version 6, 7, and 8. However, what happens if you need some of the functionality in Foundation 5 and also need to support IE8. Well, here are some ideas to do this. Bryan Thrasher came up with this really great solution to get the grid working in IE8 http://foundation.zurb.com/forum/posts/2049-simple-solution-for-ie8-and-foundation-5.
It involves some additional HTML, CSS, and jQuery but it can be a lifesaver. There is also a grid fix for IE8 for Foundation 4 that can be downloaded from https://gist.github.com/hatefulcrawdad/5068210. Basically, it forces IE8 to support the grid and does a pretty good job.
If you need to support IE7, you can either go to http://foundation.zurb.com/docs/ and scroll to the bottom, and download and use an older version of Foundation, Version 2 supports IE7, or you can set the Foundation 2 grid...