Cracks in basement foundation walls and floor
Hi all. I would appreciate some advice on this issue as I am getting conflicting opinions from local contractors.
I have just moved into an 8 year old house and we are looking at finishing the basement. The floor of the basement has 3 long cracks, each very narrow (1-2 millimetres at the most) with no shifting or lifting of the floor anywhere. Additionally, there are 4 very narrow cracks in the walls of the poured foundation which are visible on the inside and the outside (where they continue above ground level). The cracks in the walls are also very narrow (really just hairline cracks), but they appear to go right through the wall.
Being a fairly new house, the foundation has a properly functioning weeping tile and a dimpled plastic membrane surrounding the foundation. There is no evidence of water ingress anywhere in the basement despite heavy rainfalls and despite all the cracks.
The question is: do we need to repair the cracks prior to finishing the basement (floor and wall)? If so, what is the best approach to fixing them?
I have talked to several contractors who have told me that the cracks do not need to be repaired because the waterproofing membrane and weeping tile will prevent hydrostatic pressure from building up, thereby preventing a leak through the foundation cracks. I am really not sure whether I trust this advice.
Any insight from forum members?