In this blog post I wanted to take about installing chimney base sheet and how we install the base sheet around the chimney before install chimney flashing. you’ll see exactly what I’m talking about.
Chimney flashing repair before pictures
Chimney flashing repair after pictures
This is the chimney we will be talking about today. You can see from this picture that this chimney has a lot of leaking problems. I’m going to shown how we install the base sheet around the chimney in such a way that if the metal flashing ever fails the base sheet we install will keep the water from getting into the house.
Chimney base sheet rolled out in to the valley
If new decking has to be replaced around the base of the chimney we like to install it as tight as we can but still allow for expansion. You can see from this picture that after the decking is installed we roll the base sheet out so that it starts from the base of the chimney and we roll it out in to the valley that already has the base sheet installed. WE do it like this because if water dose get in it will just follow down the base sheet in to the valley and off the roof.
Chimney base sheet
Next we install the rest of the base sheet all the way around the base of the chimney. The sheets are in stalled so that each sheet over laps over the top of the bottom sheet. That way if water gets in it will just follow all the way down the sheet to the valley and follow off the roof.
caulking base sheet
The base sheet is truned up 2″ around the base of the chimney and sealed. After doing all this you will have a water prof chimney and if water ever dose get in past the metal flashing the water will just follow down the base sheet and run out the bottom of the roof.
Chimney base sheet installed
We take the same care with installing the metal flash.