I have a paver patio that heaved 2" last year. After talking to several contractors, blogs and an envrionmental engineering firm, they all recommended insulating under the pavers using rigid foam insulation. They would not let me know how to best install the insulation without charging me a ridiculous amount of money which I would rather spend on actually fixing the issue. I am looking for advice on how to install this for the best results. The current patio pavers are on 4" of crushed limestone, then landscape fabric, then 18" of 3/4 washed stone and a drain tile system running to daylight. The issue is that there is ground water 42" below grade which is freezing causing the heaving of patio and deck. The patio faces north and does not get a lot of snow cover in the winter. I live in central WI. I would appreciate any input and thanks for your help!