End Dams - Do You Really Need Them?
Recently an architect called me for masonry advice on a flashing end dam and how effective these are. He asked “do we really
need them for this project”?
End dams were non-existent when I started to lay brick and flashing was either PVC or copper. These devices were added to the
flashing system in mid-1980. The purpose of the end dam is to divert the water that is collected by the flashing to where the flash
ing ends and the end dam diverts the water out of the wall via a weep. All the good that flashing does in directing water out of the
wall is lost if there is no end dam. Yes! Mr. Architect you do need these!
End dams are prefabricated or can be field-formed
in the field with the flashing being used.
In a proper installation, the prefabricated end dam is installed first at the end of where the through-wall flashing stops and the through wall flashing lays over the top of the end dam. The proper lap, primer and mastic recommended by the flashing manufacturer must be incorporated into this installation for success.
It is also possible to fold and make an end dam in
the field. The flashing needs to extend beyond the
point of the head joint it will stop at by 1” -2”.
Fold it up at a 90 degree angle to fit into the head
joint. Make a cut horizontally and place the vertical part of the flashing into the cup you have created and you have an end dam. Make sure mastic is
used to seal this end dam to make it water tight.
Find these drawings at: http://imiweb.org/masonry-detailing-series
If you have questions about Masonry End Dams or other masonry topics call Gary Porter at 847-297-6704 or send an
email to gporter@masonryadvisorycouncil.org.
The Masonry Advisory Council provides FREE masonry advice
to Architects, Engineers, Contractors, Developers, and the general public in the Chicagoland area.
Visit our website for other helpful masonry tips at masonryadvisorycouncil.org
