When a chimney does not have to be aesthetically pleasing then wrapping it with a rubber membrane will be the most inexpensive way to seal it.
Rubber roofing around chimney.
Roof flashing around chimneys can separate from the brick allowing rainwater to leak inside the house.
Seal the sides of the chimney with prebent pieces of step flashing under each course of shingles photos 4 and 5.
Place shingles over the flat part of the saddle.
A very cost effective but a long lasting solution to take care of a chimney.
Slide the prebent and soldered chimney saddle into place behind the chimney.
There are not many roofing contractors that will offer such a service but anyone that knows how to do a torch down roofing system should be able to do it.
It is a time consuming process.
Along the edges or closer if necessary to flatten the metal.
Nail the shingles and saddle into the roof.
Http amzn to 166s7k0 rubber roof repair this video demonstrates how to install outside corner flashing on a rub.
Secure the chimney saddle.
Galvanized roofing nails about every 6 in.
In most cases it is essential to use a skilled craftsman to wrap a layer of the rubber material into a step flashing and then counter flash with aluminum or copper.
Clean any leaves or other debris out of the gap between the flashing and chimney.
How to fix a leaky roof by a chimney.
If you notice water stains on the ceiling near a fireplace and the roofing isn t damaged there s a good chance the chimney flashing needs attention.
Nail it to the roof along the top edge.
Use a hammer and roofing nails to attach the saddle to the roof.
Fit the chimney saddle around the back of the chimney.
Rubber repair kit available on amamzon.
Instead sealing the chimney crown with a liquid sealant we used a rubber membrane the flashing on a chimney is one of the biggest reasons for roof leaks.
Insert roofing nails into the saddle and roof every 6 inches 15 2 cm.
The easiest way is to wrap it with a membrane.