Before you order epoxy for an L-shaped countertop, split the top into two rectangles. Count the corner once, then subtract the sink opening. The area left on your sketch is the area your flood coat needs to cover.
Grab a tape measure, a pencil and a sheet of paper. This example takes you from the first measurement to the kit sizes you can buy.
Measure each run once
Sketch the countertop from above. Draw a line across the inside corner to make two rectangles. Give the corner to the long run. Measure the short run from the line you drew to its far end.
Measure the length and depth of each rectangle in inches. Measure to the finished edge so the overhang is included. Use the actual depth of each run, especially if one is deeper than the other.
Multiply length by depth for each rectangle. Add the two areas, then divide by 144 to convert square inches to square feet. For help drawing the layout, see Hartson-Kennedy's countertop measuring guide (PDF).
Subtract the sink opening
Measure the opening in the countertop from inside edge to inside edge. Multiply its length by its width. Subtract that area from the top. If the sink stays in place, use the outline of the area you will mask off.
For a rounded or irregular opening, trace its shape to estimate the area more closely. Keep the vertical cut edge and any backsplash on separate lines in your notes if you plan to coat them.
An L-shaped countertop with 21.5 sq ft to coat
In this example, the long run is 96 inches by 24 inches. The short run adds another 48 inches beyond the corner. The sink opening is 24 inches by 15 inches.
| Part | Size (in) | Area (sq ft) |
|---|---|---|
| Long run A | 96 x 24 | 16.0 |
| Short run B | 48 x 24 | 8.0 |
| Sink opening | 24 x 15 | -2.5 |
| Area to coat | 21.5 | |
Turn the area into an epoxy order
For one 1/8-inch flood coat, POURLA Countertop Epoxy covers about 12.5 sq ft per mixed US gallon. Divide 21.5 by 12.5 to get 1.72 gallons for the top. Use the coverage rate for the resin and thickness you plan to use. See the POURLA Countertop Epoxy technical data sheet (PDF).
If bare wood needs a seal coat, plan it as a separate coat. For exposed edges, the POURLA calculator's 15% allowance is based on the flood coat. Tall vertical faces or a backsplash need a separate estimate. See our guide to sealing wood before epoxy.
Use fluid ounces to add the three amounts. One US gallon holds 128 US fluid ounces. See NIST's measurement tables (PDF).
| Material | How to estimate it | US fl oz |
|---|---|---|
| Flood coat | 1.72 gal x 128 fl oz per gal | 220.16 |
| Seal coat | 21.5 sq ft x 1 fl oz per sq ft | 21.50 |
| Edge allowance | 15% x flood-coat volume | 33.02 |
| Mixed material, about 2.15 US gal | 274.68 | |
With both extras included, two 1-gallon kits would come up short. For this example, two 1-gallon kits plus one 64-fl-oz kit give you 2.5 gallons of mixed material. If you buy only the 1-gallon size, round up to three kits. Check both sizes on the POURLA Countertop Epoxy product page.
Use 21.5 sq ft in Total area if that option is available. A form with length and width fields can use 129 in x 24 in for this example. It represents the same coated area. Turn on seal coat and edges only when your project calls for them.
Keep your seal coat and flood coat quantities on separate lines for pour day. Use the product instructions to plan each batch. Once you have the material, follow our countertop pouring guide to get the surface ready.