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Drip caps/end dams

Inspector Gadget

Registered User
Joined
Mar 5, 2020
Messages
778
Location
New Brunswick
Morning folks.

We're having a bit of a discussion/debate in our office about the merits of enforcing the requirements of drip caps with end dams per CSA A440.4 10.2.2.1(d)/ NBC 9.27.3.8(4).

With the combination of modern window brickmolds and flashing tape, is there a functional necessity for a drip cap with an end dam? Moreover, if there's a logical argument for a drip cap at the top of the window, if a suitable cladding material is sealed or otherwise attached to the window itself, what's the logic/merit/argument for the end dam?

Thoughts?
 
We require drip caps, but the end dams are not a hill we will die on.

The drip cap flashing is not just required by the code, but also the A440.4 installation standard, which is driven by the window manufacturer industry.

It's also required by Atlantic Home Warranty.
 
I know inspectors in neighbouring municipalities that consider the newer vinyl windows to be self flashing, so they interpret these windows as meeting code requirements.

I think end dams are critically important in an environment where the walls are constantly getting wet, and I require them.
 
I know inspectors in neighbouring municipalities that consider the newer vinyl windows to be self flashing, so they interpret these windows as meeting code requirements.

I think end dams are critically important in an environment where the walls are constantly getting wet, and I require them.
I've heard this argument as well. It's driven by the siding guys who don't want to install the drip cap. Ask them for the documentation that the windows are self-flashing and do not need drip caps. They swear it exists. I've been waiting years to get it.
 
The problem is that many vinyl windows have a groove all around the perimeter for the siding to slide into. Water will run down the siding into the top groove, vhich will take it to the end of the window and just dump it. Some of the water will end up going behind the siding. A drip cap prevents this.
 
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