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Home / Exterior Products / PROSOCO R-Guard Fluid-Applied Barriers

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PROSOCO R-Guard Fluid-Applied Barriers

Cat 5 bonds to damp substrates and tolerates rain right after application — which is why we reach for it on Seattle, Bellevue, Tacoma and Everett jobs.

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PROSOCO R-GuardFluid-applied air & water barrier
Installed by Side-Pro Exteriors across Seattle, Bellevue and Tacoma

Cat 5 is the only barrier we install that will bond to a damp wall and take rain the same afternoon. It still will not cure below freezing.

R-Guard is PROSOCO’s fluid-applied system — rolled, brushed or sprayed straight onto the sheathing, curing in place into a continuous membrane with no seams, no laps and no fastener penetrations. Cat 5 handles the field of the wall, FastFlash the rough openings, Joint & Seam Filler the sheathing joints.

For a Pacific Northwest job the wet-weather tolerance is the genuine headline. Cat 5 bonds and cures in wet weather, may be applied to damp substrates, and tolerates rain immediately after application. Very little else in the category will do that, and on a re-side that opens a wall in November it changes what is possible.

The limit is temperature, not moisture. PROSOCO requires substrate and air between 32°F and 110°F for the material to cure; applied below freezing it simply sits there until a thaw. The product and the sprayer also need to be at 60°F or above to spray properly. So “installs in any weather” is wrong. “Installs in wet weather above freezing” is right — and across Seattle, Bellevue and Tacoma that covers most of the year.

Cat 5 is also one of the few products in this category whose air-barrier claim is fully supported. It publishes both an ASTM E2178 material result and an ASTM E2357 assembly pass, and it is rated for up to twelve months of exposure before the cladding goes on.

PROSOCO does not publish a warranty period, and we will not invent one. The limited warranty printed on its data sheets warrants the product free from defects and limits liability to supplying enough material to re-treat the affected area — no duration, no labor. There is an enhanced warranty under PROSOCO’s R-Guard Promise program, but its terms are not published and are arranged project by project. Note also that every figure above is Cat 5’s specifically: FastFlash, Spray Wrap MVP and AirDam each carry their own perm, UV and temperature limits.

Key Features & Benefits

  • It cures in wet weather. Cat 5 bonds to damp substrates and tolerates rain immediately after application. Almost nothing else in the category will.
  • No seams, no laps, no fastener holes. Rolled, brushed or sprayed on, curing into one continuous membrane across the whole wall.
  • Air barrier, properly evidenced. Both ASTM E2178 material and ASTM E2357 assembly passes at 0.0007 L/s·m² — one of the few products here whose air-barrier claim is fully supported.
  • Twelve months of exposure. Rated for up to a year of UV and weather, which takes the schedule pressure off almost entirely.
  • A complete detailing system. FastFlash at rough openings, Joint & Seam Filler at sheathing joints, AirDam at window perimeters, Cat 5 across the field.
  • 14 perms wet cup, 10 dry. Vapor-open enough to dry outward while still controlling inward drive.
  • It will not cure below freezing. Substrate and air must be between 32°F and 110°F, and the product and sprayer need 60°F to spray properly. Wet is fine; frozen is not.
  • Complex geometry is where it wins. Every inside corner, penetration and transition gets the same continuous membrane, with nothing to lap or tape.

Why Choose Side-Pro

Fluid-applied is the only barrier that lets us open a wall in November and close it properly the same week.

On a Pacific Northwest re-side the real enemy is the calendar. Sheet products want a dry substrate and a dry day; get neither for a fortnight and the wall sits open. Cat 5 changes that equation because it bonds to a damp face and takes rain within the hour. What it will not do is cure below freezing — applied in a hard frost it simply waits, sitting uncured on the wall until a thaw arrives.

Applied to a measured thicknessWet film thickness checked as we go, because a fluid barrier is only as good as the film it leaves behind
Temperature, not moistureWe work to the 32°F floor and keep product and sprayer warm enough to atomise properly
Openings firstFastFlash at every rough opening and transition before the field coat, so the detailing is continuous rather than patched

We are trained in R-Guard application and work on residential and commercial envelopes across Seattle, Bellevue, Tacoma and the wider Puget Sound region — through the wet months as much as the dry ones.

Need to open a wall in the rain?

Fluid-applied is the system that makes it possible. Ask us what it costs against a conventional sheet product.

  • Free estimate and inspection, with no obligation
  • Licensed, bonded and insured — WA reg. SIDEPI*008N1
  • Siding, roofing and exteriors across Puget Sound since 1995

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Frequently Asked Questions

Is fluid-applied WRB worth the added cost for a typical Seattle home re-side?

For standard residential re-siding, the added cost of fluid-applied WRB is generally not necessary—Tyvek or VaproShield provides excellent performance. Fluid-applied systems like Prosoco R-Guard are most cost-effective on new construction where substrate access is easy, on high-performance or certified projects, and on commercial buildings where air barrier continuity requirements are strict.

How does Prosoco R-Guard perform in Seattle's wet, cold application conditions?

Prosoco R-Guard products have specific temperature requirements—generally above 40°F surface temperature—and require dry substrates for proper adhesion and curing. Side-Pro monitors conditions carefully and schedules application during appropriate weather windows.

Can Prosoco Fast Flash replace traditional window pan flashing in Seattle homes?

Yes. Prosoco Fast Flash is widely used as a fluid-applied alternative to self-adhered sheet flashing at window and door sills and jambs. Its ability to coat complex geometries and self-flash rough opening corners makes it a superior detail in many applications.

What siding systems are compatible with Prosoco R-Guard?

Prosoco R-Guard is compatible with all major siding systems including fiber cement, metal panels, wood, and rainscreen assemblies. The cured membrane provides an excellent substrate for WRB-contact siding and a proven base for rainscreen drainage mat and furring strip installation.

What Our Customers Are Saying...

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Please fill out our FREE ESTIMATE / INSPECTION form or call today to discuss your roofing or siding project with our friendly staff.

Office: 425-486-4777
Toll-Free: 1-800-743-3132
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Address:
17270 Woodinville-Redmond Road NE
Suite 700
Woodinville, WA 98072

Side Pro Exteriors is a locally owned and operated siding, roofing and exterior renovation company since 1995. We provide roofing and siding replacement to over half of Washington State including King Snohomish and Pierce counties.

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By providing your phone number and pressing submit, you agree to receive reoccurring text communications at the number provided. Message frequency may vary. Reply STOP to unsubscribe or HELP for help. MSG & Data rates may apply.