KST041321 Uniflex Single-Ply Acrylic Base Coat, Gray
- Single-ply base coat
- Sold by the pail
The base coat written for weathered single-ply roofs under the acrylic system. A gray cross-linking acrylic listed for weathered EPDM, Hypalon (CSPE) and TPO, it must be topcoated with an elastomeric finish coat, and it never goes under Silicone44. Stocked in 5-gallon pails and 55-gallon drums.
Key benefits
- Cross-linking acrylic rather than a general-purpose elastomeric: the chemistry is chosen for weathered membrane, which is what the substrate line names
- Substrate line is explicit: weathered EPDM, Hypalon (CSPE), TPO and other single-ply membranes the data sheet lists
- A base coat only: the manufacturer states it must be topcoated with an elastomeric finish coat, so the system is never left half built
- Part of the acrylic system only: Uniflex puts no base coat under Silicone44
- Gray under a white finish coat, so the topcoat pass is easy to read from the roof
Priced per project
Send the quantity and the delivery ZIP. We reply within one business day.
Request a quote Ask a question about this product
In stock Confirm the quote, and your order ships in 1–3 business days from confirmation.
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Overview
Single ply is not metal and it is not asphalt, and KST041321 exists because of that. It is a gray cross-linking acrylic base coat, and the manufacturer’s substrate line names the roofs it is for: weathered EPDM, Hypalon (CSPE), TPO and the other single-ply membranes its data sheet lists.
Two rules come with it. It is a base coat only, and the manufacturer states it must be topcoated with an elastomeric finish coat. And it belongs to the acrylic system: Uniflex never puts it, or any acrylic base coat, under Silicone44. The acrylic sequence on a membrane roof is fixed. On EPDM: KST038620 Bond-It as the cleaner primer, this gray base coat with KST020385 polyester fabric at the details, then KST041300 or KST041500 as the finish coat. On TPO and Hypalon: a pressure wash, then this base coat, then the finish coat; the wash primer is an EPDM product and stays off them. For an acrylic finish on PVC, Uniflex’s single-ply specification covers it and the adhesion test settles the build-up.
Application
- The membrane has to be clean, dry and sound. Ballast, debris, loose plates, torn seams and ponding water are prep work, and they come first.
- Prime by substrate. On EPDM that means the wash primer, applied, rinsed and dried as its own data sheet states, before this coat goes on. TPO, PVC and Hypalon are pressure washed instead.
- Reinforce the details before the field: open seams, fastener plates, curbs and penetrations take fabric or tape bedded into this base coat.
- Apply at the rates, film build and coat count in the manufacturer’s product data sheet, inside its temperature window.
- Topcoat it with an acrylic finish coat. The base coat is not a finished surface, and the recoat window in the data sheet is the one to work to.
Ordering
KST041321 is stocked in the 5-gallon pail and the 55-gallon drum. Stocked material ships in 1 to 3 business days; anything not on the shelf is ordered in and runs 1 to 2 weeks. Drums, pallets and freight go through the quote form with your part numbers, quantities, site ZIP and dates. Send the membrane type and the area, and the quote covers the primer, the base coat, the reinforcement and the finish coat for that membrane; every price here is quoted per project.
Where it's used
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Weathered EPDM
Aged black EPDM cleaned with the Bond-It wash primer KST038620, rinsed and dried, then base coated in gray before an acrylic finish coat closes the system.
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Hypalon
Older Hypalon (CSPE) membranes, named on the substrate line: pressure washed, base coated, then finished in acrylic. It is the route for a Hypalon roof that drains; no Uniflex silicone document covers Hypalon.
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TPO and PVC
Weathered TPO, also on the substrate line, pressure washed and base coated with no wash primer. For an acrylic finish on PVC, Uniflex's single-ply specification covers it and the adhesion test settles the build-up.
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Seams, plates and penetrations
The coat that beds polyester fabric or seam tape over open seams, fastener plates, curbs and penetrations, so the detail work ends up inside the system.
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Large membrane roofs
Warehouse, retail and institutional single-ply roofs where restoration is being priced against replacement and the membrane is still sound enough to coat.
Specifications
| Manufacturer | Sherwin-Williams (Uniflex line) |
|---|---|
| Part number | KST041321 |
| Color | Gray |
| Pack sizes | 5-gallon pail, 55-gallon drum |
| Not used | Under Silicone44: the silicone systems take no base coat |
| Technology | Cross-linking acrylic |
|---|---|
| Recommended substrates | Weathered EPDM, Hypalon (CSPE), TPO and other single-ply membranes the data sheet lists |
| Role in the system | Base coat; must be topcoated with an elastomeric finish coat |
| SKU | CY-KST041321 |
|---|---|
| Sold by | Pail |
| Lead time | In stock · 1–3 business days |
| Warranty | Goods are warranted to match their description and to be free of manufacturing defects when delivered; any manufacturer system warranty is issued by the manufacturer under its own terms |
Delivery and lead time
- Ships in 1–3 business days from order confirmation. Your quote states the delivery window before you commit.
- Pails, rolls and cartons ship by parcel or pallet; drums and totes by freight to your site. Tell us about lift-gate, access or unloading needs when you ask for a quote.
How to order
- Send the quantity, the site ZIP and your timing.
- A person sends one written quote with the delivered price and the ship window. We reply within one business day.
- Confirm the quote, and your order ships in 1–3 business days from confirmation.
Questions
- Can I leave this as the top layer?
- No. The manufacturer states that it must be topcoated with an elastomeric finish coat. KST041300 is the premium acrylic white and KST041500 the commercial grade; both are listed over EPDM and Hypalon among other substrates.
- What goes on before it?
- On EPDM, KST038620 Bond-It, the clear water-based wash primer the manufacturer calls a cleaner primer, rinsed off and left to dry. On TPO, PVC and Hypalon, a pressure wash and nothing else: the wash primer is for EPDM only. The data sheets set the order and the drying time between coats.
- Can it go under a silicone coating?
- No. Uniflex never puts an acrylic base coat under Silicone44; its silicone specifications go straight from the prepared membrane to the silicone. This base coat belongs to the acrylic system, under KST041300, KST041500 or another acrylic finish coat.
- Why a different base coat for single ply?
- Because weathered membrane is a different adhesion problem from metal, concrete or asphalt. The manufacturer specifies a cross-linking acrylic here and names weathered EPDM, Hypalon and TPO on the substrate line.
- How are the seams handled?
- Polyester fabric or seam tape bedded into this coat at seams, fastener plates, curbs and penetrations, then coated over. KST020385 is the 40-inch fabric roll and narrower widths are stocked for tighter work. On Hypalon, the butyl seam tape is the detail product listed for the membrane.
- Pail or drum?
- Both are stocked. Send the roof area, the membrane type and the site ZIP through the quote form and the quote states the pack count, the delivered price and the ship window.
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Trade & projects
Pricing a whole roof, or ordering drums and totes?