Stucco wrap test

                wrap vs. tarpaper Stucco
                wrap vs. tarpaper
Stucco wrap sure has some impressive data.
Click here to visit their web site.
Claiming 30% more flexural strength in stucco, and on and on, it seems that this is greatest thing to happen to stucco since portland cement.
My two test samples, tarpaper and
Stucco wrap are put on plywood. Then,
portland cement mortar is spread on to
a thickness of 3/4", the standard thickness of a stucco basecoat.
                wrap vs. tarpaper Stucco
                wrap vs. tarpaper
After 3 days, the tarpaper shows quicker
drying than the StuccoWrap. If mortar dries
out before it sets, this could weaken the mortar.
Conventional tyvek traps water against
the back side of the mortar, and never
sets all the way, weakening the stucco as well.

"Tyvek® StuccoWrap® is better than Grade D paper at managing hydration and remaining stable during curing. These two features result in a dramatic reduction of cracking in the scratch coat"

There were no shrinkage cracks in either sample.

After 5 days, the blobs of mortar were 
peeled away for further testing.
The mortar popped right off the StuccoWrap but had to be peeled off the tarpaper,
indicating the tarpaper is porous allowing
mortar to bond as well as breath on the backside for curing.
                wrap vs. tarpaper Stucco
                wrap vs. tarpaper
Tarpaper sample is scratched with a margin trowel to test for strength on the back side. It took the same amount of pressure to
scratch the StuccoWrap sample. A tie race
so far.
                wrap vs. tarpaper        Tarpaper wins !

I stood up the samples and kicked
them hard enough to break them.
I had to kick the tarpaper sample a lot harder to break it.
So much for:
"up to 30% more flexural strength"
as claimed by the StuccoWrap people.
 There you have it, as Morley Safer says on 60 minutes.