We live in a house with a stone foundation, which seeps water in the spring and during extended heavy rainfall. Several years ago, we did some repairs on the walls, which has cut down on seepage. We have also done some landscaping, where possible, to assist with drainage, but it has not stopped completely. We would like to insulate the basement to cut down on heat loss. Any suggestions?

It would not be a good idea to insulate the stone foundation from the inside if you are experiencing any moisture problems. Even if you have applied a special coating that holds back moisture, there will still be moisture in the mortar joints between the stone. The problem with this is that the foundation wall is being heated from the inside by your home heating system. If you insulate the stone wall, it will no longer receive heat and the temperature of the wall will drop when the outdoor temperature drops below freezing. Then, moisture in the wall will freeze and expand, causing the foundation to weaken and break apart. Other problems like mould growth, rotting of the structure, or rusting, will take place if moisture is trapped behind the insulation. Also, indoor air quality may become an issue if mould appears. The best way to insulate a stone foundation is from the outside and, unfortunately, it is the most expensive way. Trenching around the building would be necessary to apply parging, damp proofing, drainage systems and insulation. One other consideration - how fragile is the stone foundation? Sometimes removing soil with machines might cause damage to the foundation or weaken the structure, and this damage could raise costs further, depending on the extent of the damages. Providing good drainage on the exterior of the building was a great thing to do, but with stone foundations, moisture may always be a risk.