Rigid Foam Insulation Question?

I am planning on installing an egress window in my basement. After looking at all the well options, some of the custom built timber wells appeal to me. So my quesiton is how these timber wells are constructed. From many of the pics I have seen online, the timbers are stacked on top of each other. What is holding the timbers against the basement foundation? And what is preventing the timbers from bowing into the well? Thanks

Due to town construction, groundwater is being diverted to my basement. Water is coming up through the middle of the floor, as well as entering through the cinderblocks in the front of the house. (they refuse to acknowledge my existence, and yes, I am taking legal action). In the meantime, I need to fix this problem...I have a sump pump in one corner of the basement that runs continuously, as well as an automatic surface pump in the middle of the basement, which also runs continuously, yet this does not get rid of all the incoming water. In addition, my cement floor is now eroding away, causing the water to enter faster. I have gotten estimates from 2 different companies that install inside perimeter drains (both are roughly $5k). Will this method solve the problem of water entering the middle of the basement? I have also tried contacting landscape contractors to get estimates on an outdoor solution, yet no one has called me back. Do I need to contact an excavating company? Or some other type of contractor? Also, will digging a perimiter drain Outside the house fix the problem of the water coming in from under the house? Thanks in advance for any advice as to how I can end this nightmare! PC