Add on or replace with new?

[Leanne Kuhlman]

My husband and I own a double wide on private land. Our home has 2 kids' bedrooms and a master suite. We are considering either adding on to our existing home or, if possible, selling the double wide, having it moved off of our land and installing a triple wide. We need at least 1 extra bedroom. We have a crawl space with a full concrete foundation. I've heard of smaller "tag units" as well. Which one of these ideas, in your opinion, would be more cost effective and a better solution?

Thanks,
Leanne in Washington State (Pierce County)