Vent stacks

As usual, the devil lies in the details! And those readers who carefully watched the torch down installation video may have noticed that we had two roof penetrations that were not addressed yet: the two bathroom vent stacks.

To integrate the vent stacks into the roofing system, they were fitted with a lead sleeve.

Our roofer Pablo began by applying roofing cement around the collar of the vent stack and painting a square base that was the same size as the square base of the lead sleeve.

I had cut the vent stack down so that it would fit the lead sleeve. Pablo slid the lead sleeve over the vent stack and set the base onto the roofing cement square. He continued by folding the top of the sleeve over the top of the vent stack.

This does seal the top of the vent stack, but more work was needed to seal the collar, or the square base of the sleeve. To start, Pablo placed a square piece of base sheet over the square sleeve base. The base sheet piece was about twice the size of the square sleeve base.

He also had cut a piece of torch down membrane that was about four inches wider than the base sheet. He heated up the bottom of the torch down membrane piece, slid it over the vent stack and firmly pressed it onto the base sheet.

Did you notice the rounded corners on the torch down membrane? Pablo explained to me that it is best practice to round off corners, because square corners tend to come loose over time. He continued to go around the edges of the torch down membrane and made sure it was fully adhered and sealed.

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About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

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