Why does the data sheet mention pH?

Because concrete is alkaline and how alkaline decides whether a coating sticks. The manufacturer states a range of 6 to 13 for this primer, which is wide but not unlimited. Test the surface and read the sheet before ordering.

What goes over it on a concrete deck?

KST041320, the gray premium acrylic elastomeric, is listed as a base coat on concrete, and KST041300 is the premium acrylic white finish coat over it. The data sheets state the film build, the coat count and the recoat windows.

Does a concrete deck always need a primer?

No. Under Silicone44, clean concrete cured at least 29 days, with moisture at 15% or less and sealers and release compounds removed, takes the silicone directly, with no primer and no base coat. Under the acrylic system the data sheet decides by substrate and condition. Send the deck type, its age and what is on it now with the quote request.

What about ponding water and low spots?

Those are corrected before anything is primed. KST0SLPBD, the Slope Builder compound, is listed for building up low-lying areas near drains, in valleys and along parapet walls ahead of a fluid-applied system.

What size does it come in?

The 5-gallon pail. Put the deck area on the quote request and the quote states the pail count, the delivered price and the ship window; pallets and freight are priced on the same quote.

Base coats & primers

KST036500 Uniflex Acrylic Concrete Primer, White

Concrete primer
Sold by the pail

The acrylic concrete primer in the Uniflex line, for cured concrete decks and parapets going under an acrylic elastomeric system. Its substrate line covers concrete and surfaces with a pH of 6 to 13, and it is stocked in 5-gallon pails and quoted per project.

Key benefits

Written for concrete, with an unusually specific substrate line: concrete, and surfaces with a pH of 6 to 13
Acrylic and water based, which keeps it in the same family as the acrylic elastomeric base coats and finish coats above it
White, so coverage on a gray deck is easy to read before the base coat goes on
One pack size, the 5-gallon pail, which suits decks, parapets and the details between them
Part of the acrylic system on concrete; under Silicone44, clean cured concrete takes no primer and no base coat

Priced per project

Send the quantity and the delivery ZIP. We reply within one business day.

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In stock Confirm the quote, and your order ships in 1–3 business days from confirmation.

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Shipping & returns

Overview

Concrete is its own problem. A deck can be sound and still be too alkaline or too smooth for a coating to grip, which is why the Uniflex concrete primer carries a substrate line most primers do not: concrete, and surfaces with a pH of 6 to 13. KST036500 is that primer, white, acrylic and water based.

It is the first layer of the acrylic concrete-deck system, not the whole of it, and it has no place under Silicone44, which goes straight onto clean, cured concrete. We stock it in 5-gallon pails together with KST041320, the gray premium acrylic elastomeric listed as a base coat on concrete, KST041300, the premium acrylic white finish coat, KST020385 polyester fabric for cracks and details, and KST0SLPBD Slope Builder for the low spots near drains.

Application

The deck has to be clean, dry and sound. Laitance, curing compounds, oil and loose material come off before anything is primed.
Correct the low spots and reinforce the cracks first, then prime; slope and detail work do not get easier under a coating.
Prime by substrate and by test. Concrete inside the stated pH range is what this primer is listed for; take the call from the data sheet, not from the look of the deck.
Apply at the rates, film build and coat count the manufacturer’s product data sheet states, inside its temperature window.
Hold the recoat window between primer and base coat, and take cure times from the sheet.

Ordering

KST036500 comes in the 5-gallon pail. Stocked material ships in 1 to 3 business days; anything not on the shelf is ordered in and runs 1 to 2 weeks. Pails by the pallet, the drums and totes of the base coats and finish coats that follow it, and all the freight go through the quote form with your part numbers, quantities, site ZIP and dates. Every price here is quoted per project against the roof in front of you.

Where it's used

Concrete roof decks

Cured structural concrete decks being restored with a fluid-applied system rather than re-roofed, where the primer settles adhesion before the base coat.
Parapets and upstands

Concrete parapets, curbs and upstands around a deck, primed with the same material as the field so the details and the flat area stay one system.
High-alkalinity surfaces

Concrete whose surface pH is on the high side, which is why the data sheet states a pH range of 6 to 13 rather than leaving it to judgment. Test the deck and read the sheet.
Lightweight and structural concrete

Roof surfaces poured in concrete of either kind, primed ahead of the gray acrylic elastomeric base coat and a white or tinted finish coat.
Detail and low-spot work

Bought with the slope-building compound and polyester fabric used to correct ponding areas and reinforce cracks before the field is coated.

Specifications

Specifications: KST036500 Uniflex Acrylic Concrete Primer, White
Manufacturer	Sherwin-Williams (Uniflex line)
Part number	KST036500
Color	White
Pack sizes	5-gallon pail

Performance
Technology	Acrylic
Recommended substrates	Concrete; surfaces with a pH of 6 to 13
Role in the system	Primer beneath an acrylic elastomeric base coat on concrete

Ordering
SKU	CY-KST036500
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.

Shipping & returns

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.

Request a quote

Questions

Why does the data sheet mention pH?: Because concrete is alkaline and how alkaline decides whether a coating sticks. The manufacturer states a range of 6 to 13 for this primer, which is wide but not unlimited. Test the surface and read the sheet before ordering.
What goes over it on a concrete deck?: KST041320, the gray premium acrylic elastomeric, is listed as a base coat on concrete, and KST041300 is the premium acrylic white finish coat over it. The data sheets state the film build, the coat count and the recoat windows.
Does a concrete deck always need a primer?: No. Under Silicone44, clean concrete cured at least 29 days, with moisture at 15% or less and sealers and release compounds removed, takes the silicone directly, with no primer and no base coat. Under the acrylic system the data sheet decides by substrate and condition. Send the deck type, its age and what is on it now with the quote request.
What about ponding water and low spots?: Those are corrected before anything is primed. KST0SLPBD, the Slope Builder compound, is listed for building up low-lying areas near drains, in valleys and along parapet walls ahead of a fluid-applied system.
What size does it come in?: The 5-gallon pail. Put the deck area on the quote request and the quote states the pail count, the delivered price and the ship window; pallets and freight are priced on the same quote.