[Greenbuilding] Exterior insulation retrofit

JOHN SALMEN terrain at shaw.ca
Mon May 23 10:10:00 PDT 2011

Hi John
The original reference was from a current NZ eifs manuf spec. Sheet (BRANZ
appraised) which required a .45 factor for derating anything outboard of the
sheathing. The standard was NZS 4214 which is pretty old - here is an info
sheet from BRANZ 

I don't know how the current standard has changed as I couldn't access any
free versions of it but assume the drating is still in effect.

As for the liquid membrane we will be  using it. I'm pretty curious and the
ext walls are all engineered shear walls so movement has been limited. To be
honest the product application specifications I think put it in the grey
area of overall credibility. Legally I think the liability is so diffused
that the product cost is probably more related to managing risk than

-----Original Message-----
From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of
Sent: May-23-11 8:22 AM
To: Green Building
Subject: Re: [Greenbuilding] Exterior insulation retrofit

Hiya John
Liquid applied membranes, at least the ones out there, are all significantly
superior to mechanically attached sheet membranes.
They can be applied to plywood or non-paper-faced gypsum (the paper facing
was of course the biggest problem, not the gypsum).
They all require joints to be treated with a tape of special mastic before
roller/spray applying the membrane.
I attach two photos of non-EIFS systems, but all the EIFS folks have their
own as well.
Even Tyvek now has a fluid applied air and warter barrier as part of its
CCMC has tested these systems and included the testing of movements and
drainage. I have tested several for drainage, and water resistance.
In every way, except cost (they are more) and weather-sensitivity during
construction (they need to cure before it rains), these fluid membranes are
superior in performance, often significantly.

I know of a lot of work done at BRANZ, and have collaborated with them on
their ventilated wall research, but I have not seen them tackle the heat
loss question yet.  Any idea where this 20% (which seems very high) comes
from? Could not find it by googling.

More information about the Greenbuilding mailing list