We have a chimney issue that we need to fix. Unfortunately, our builder used metal flashing around the base of the chimney at the roof line. This is eventually is going to start leaking. The stonework is not brick and is cut field stone so it is difficult to flash up against. The only idea that we have been able to come up with is to remove the metal flashing and replace it with a concrete collar. We are thinking of using lightweight foamed concrete to avoid any weight stress issues on the roof itself. We are thinking of putting a bevel on top of the concrete collar to have the water shed away from the chimney. The concrete collar would then have straight edges that the roofers could then flash up against. We have a multi-pitched roof where the chimney comes out of the roof line. I guess what I would like to ask everyone is:
1) Has anyone had a similar situation and how did they resolve it
2) Does anyone know anyone that specializes in lightweight foamed concrete? We are located in Michigan.
Hopefully, everyone can see the picture.