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Stucco Flashing Details - Sidebar

Sticking Caulk to Paper: A Hands-On Comparison

 

I have experimented in my shop to find out how well various caulks and tapes stick to different types of paper. Some of the 12-inch-square paper samples I used were fresh out of the box, others approximated the damp or dusty condition of a job site. I applied three beads of sealant: a 3/8-inch bead right out of the tube; a 3/8-inch bead which I tooled to flatten it; and another flattened bead used to adhere a second piece of paper. I allowed the samples to dry for about 48 hours, then submerged them in water for 72 hours. This level of exposure to water is severe, but I felt that it was justified because I have worked on jobs where caulk was exposed to heavy rain and runoff for 24 hours or more. After taking the samples out of the water, I pulled and tugged the beads to see how well they had adhered. The results, which are shown in the chart below, aren't scientific, but are based on careful observations from which I was able to form an opinion about which caulks worked best relative to the others.

In general, the tooled caulk adhered better than the straight 3/8-inch bead, probably because of the increased surface area. Most of the caulks didn't stick well to Tyvek Stuccowrap, possibly because of its ridged surface. Two of the caulks -- VIP's Elastomeric Ter-Polymer and Polyseamseal -- softened significantly and all but lost their adhesion. Clearly, the Quad caulk performed best with all membranes. Three other caulks -- Rainbuster No. 900, Pro Choice Neoprene, and Dynatrol I-XL -- were close seconds. I also experimented with EZ Seal, a tape manufactured by Fortifiber consisting of hot-melt glue on paper, and with Tyvek Tape. While most contractors will not be applying saturated tape, both of these products performed well, although it was difficult to peel away the EZ Seal's backing paper to expose the adhesive, even after the tape had dried in the sun. -- R.W.

 

Base Receiving Material

 

Homewrap

Stuccowrap

60-min paper

Future Flash

Product/Manufacturer

damp dirty

clean

damp dirty

clean

damp dirty

clean

shiny dirty

dull dirty

dull clean

896 Silicone

Pecora

800/523-6688

P

P

P

P

M

M

G

G

G

Silicone II

GE

800/255-8886

P

P

P

P

P

F

F

G

G

PL Polyurethane Caulk

Chemrex

800/828-0253

P

P

P

P

G

G

G

G

G

Elastomeric

Ter-polymer Sealant VIP Waterproofing Systems

800/228-5537

F

P

P

P

P

P

P

P

P

Polyseamseal

Darworth

800/624-7767

P

P

P

P

P

P

P

G

P

Rainbuster No. 900

Top Industrial

800/473-1617

M

F

P

M

G

G

G

G

G

Quad Advanced Formula Sealant

OSI Sealants

800/321-3578

G

G

G

G

G

G

G

G

G

Pro Choice Neoprene Caulk

Gibson-Homans

800/433-7293

G

G

G

G

G

G

F

M

G

Dynatrol I-XL

Pecora

800/523-6688

F

M

F

F

G

G

G

G

G

Key:

Poor Adhesion P

Fair Adhesion F

Moderate Adhesion M

Good Adhesion G