Fireplaces, Heating Stoves, Flues and Chimneys - new flashing old chimney

I am trying to reflash and old chimney, The mortar where old flashing has been grounded out (about 1/2 - 3/4" deep). Will mastic be suficient to hold it?

Hello; honeydo58

An answer to the question is likely to be obtained from any local building materials supply store. These places sell the needed materials to local handyman and contractors.

Local building materials supply stores and or building supply yards (not hardware stores) are more likely to know how to do the project, offer helpful ideas, suggestions and or other helpful advice.

Most likely all the existing mortar excessable or already lossened will have to be removed. Installing new flashing and mortar on existing old, lossened, cracked and or deteriorated mortar will not provide a good enough base to last for a long time duration, etc.

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Yes, the mortar needs to be clean and free from debris. As this chimney is 15 years old some is deteriorating. An angle grinder is what I perfromed the slicing with in order to create a groove in which the new lead flashing wouls go. The old lead cannot be completely removed as it was placed when the bricks were laid. Thank you.

Need to know more just what you have there are want to do. Where is it at in the roof, are the step shingles good or do you have to slip new ones up in there. Is the cricket good behind the flue?. How bad is the mortar in the flue.
Not many put the counter flashing into the motar anymore. Just roof cement behind it and nail it to the chimney.

ED ;)

The house is a late80's Deck House. Roof is 3to 3.5 pitch. Location of chimney is 4' from ridge and has a skylight situated on its right side. When project started there was no chimney , now there is. As for the flue and mortar that was redone as part of his project also. I prefer the counter flashing to the mortar as a better seal. Roof cement is not the duct tape of building repairs.

Well its like how far back do you want to go here. There is a chisel made just for takening out the motar there. take and tack up over the step shingles a 6" metal or copper what ever and lay out you steps for the counter flashing. then cut the motar out for it cut the steps in the 6", bend a 3/8" 90o at all steps push into the open motar joints and set down with wedge plugs. then remotar the chimney. Make sure the cricket is set the same way in back of the chimney.

Thats why we set the counter flashing now with roof cement on the back side now.

ED ;)