

🛡️ Seal smart, build strong — don’t let gaps hold you back!
Prosoco R-Guard Joint and Seam Filler is a high-performance, single-component STPE paste designed for prepping joints, seams, and cracks before applying air and water barriers. With a fast 4-hour cure, water-resistant durability, and a fiber-reinforced formula combining silicone and polyurethane benefits, it ensures professional-grade sealing and long-lasting protection in new or existing wall assemblies.



| ASIN | B00OBUXCJ6 |
| Best Sellers Rank | #74,241 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #64 in Industrial Joint Sealants |
| Brand | Prosoco |
| Date First Available | October 9, 2014 |
| Full Cure Time | 4 Hours |
| Is Discontinued By Manufacturer | No |
| Item Form | Paste |
| Item Weight | 1.9 pounds |
| Item model number | 5824052562 |
| Liquid Volume | 20 Fluid Ounces |
| Manufacturer | Prosoco |
| Material | Silyl-Terminated-Poly-Ether (STPE) |
| Number of Items | 4 |
| Product Dimensions | 12 x 2 x 2 inches |
| Surface Recommendation | Walls |
| UPC | 653429020212 |
| Unit Count | 20 Ounce |
| Water Resistance Level | Water Resistant |
L**R
Great product
My husband absolutely loved this product. Worth the money and easy to use. Dries fast, appearance is a terracotta color when applied. Very durable and great quality. Will buy product again.
S**M
Good stuff, needed more than recommended
Worked as expected. I don’t think it covers as much as it says. We used it as recommend by Matt Risinger from the Build Show. It made it a third way around the building base (40x40) with 3 tubes. Felt like I should have made it a little thicker like the videos showed but it sealed nicely still.
M**R
Fill those gaps between any building materials!
Prosoco R-Guard Joint & Seam Filler (and related Fast Flash) works as described to seal the gaps between different building materials. Tape and caulk products aren't all-purpose as liquid flashing products, where you apply a large bead in bulk, and then spread as needed for the situation. Corners, odd shapes, vertical, horizontal, works equally well inside tight spaces as it does across large flat areas. You can push the liquid flashing into cracks in the same way that caulk is applied, plus you spread it out with a plastic fin or other spreader tool. Cleans up easy with paper towels before it dries. The finished product is a rubberish mastic that provides a permanent barrier to water, air and insects. Cure (drying) time is dependent on humidity. If you're working in a very dry environment (e.g. below 50% humidity), a small amount of water misting with a spray bottle will speed things up. I'm in central Texas and find most days that I can spread the joint and seam filler in the morning, and then after lunch apply the fast flash. On especially dry days, I'll lightly mist the substrate before applying the joint and seam filler, and then mist the finished spread after all spreading/tooling is completed. A great benefit, rain isn't a worry - you can apply these products and not worry about rain later in the day! For those that live in desert conditions, best to wait a day for each round (e.g. day 1, apply joint and seam filler, day 2, apply fast flash, day 3, continue). Note - if you apply the joint and seam filler especially thick to fill large voids, it may take longer to fully cure (dry). The joint and seam filler is pink and reinforced with fibers, designed to fill large gaps between material, goes on very thick and the finished surface isn't as smooth/flat in comparison to the fast flash. Some use the joint and seam filler by itself where other materials will cover it up, but Prosoco recommends a top coat using the fast flash product over the joint and seam filler. Fast flash can be used by itself, or on top of the joint and seam filler. Dark red in color, nearly the same product as the joint and seam filler, but less fiber reinforcement to allow being applied as a thin top-coat that finishes smooth and sexy! You can paint the fast flash product after it drys/cures. Painting the joint and seam filler isn't recommended, as it finishes with a rough surface, not intended to be visible. Paint is only necessary if you're planning to leave the finished spread exposed to sunlight (UV) indefinitely. These products are designed to be hidden behind other materials (e.g. sheathing, siding, trim, etc.) when the building is complete. Applied successfully along the foundation between concrete and base angle (e.g. sill plate) for metal buildings, workshops, and barndominiums. Also used at all penetrations, windows, doors, etc. Works great for commercial and residential construction across a wide variety of materials! Liquid flashing provides a rubber gasket-like finish that allows screws and nails to penetrate after spreading, while maintaining full waterproofing. Liquid flashing products are more expensive than tape and caulk products. Liquid flashing products are more effective, harder-to-get-wrong and thereby longer-lasting than tape and caulk products. Yes, liquid flashing is messy, but after a few projects you and/or the crew will find it easier to work with compared to tapes. I'm averaging 20~30 linear feet per 20-ounce tube of the joint and seam filler. I'm probably using a lot more than is necessary. I'm getting 30+ feet per 20-ounce tube of fast flash, and it goes on thinner. Big thanks to Matt and the Build Show Network, plus the manufacturer videos on YouTube for Prosoco, Huber, and PolyWall! Liquid flashing and spray/rolled/painted/spread weather barriers are definitely a better answer for a wide variety of use cases compared to tapes, caulks, and wraps. Welcome to the 21st century!
M**S
outside sealant
I saw this product on youtube, it was recommended to be a great product. it has fiber inside to form a strong boding agent. it Harden pretty quick . as long as the creeter stay out I'm happy a bit pricey
P**T
Prosoco Makes the Best Products for Air and Water Sealing
INstead of using a House Wrap that is supposed to be a Water Resistant Barrier (WRB), the building industry is eventually going to use a spray one or roll on liquid applied barrier. It is easier to work with and will not blow off. The other advantage is that it can be used, like this product to seal seams and holes> learned about it from watching the Build Show with Matt Risinger. So instead of using tape on all the seams and joint, you apply this from a sausage tube and spread it with a body putty spreader or any type of putty knife. Then you can apply one of the other liquid applied sealants. I am using the one that can be sprayed or rolled onto the surface. I am also going to use it as an edge application to the OSB I am using. Better safe then sorry later on.
M**4
Solid product, not so solid price increases.
Excellent product. Highly reliable and long lasting. Easy to apply and easy to clean the tips of the applicator post application for reuse or next tube. I paid $24 per tube which was a fair price but the value for money isnt there at alot of the higher prices that it gets marked up for.
O**P
Awesome product
Awesome product . great quality waterproofing
D**G
Good product
The product filled gaps. Works good good value for your money
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