ACX plywood

Overview

ACX is plywood with a sanded A-grade face, a C-grade back and an exterior-type glue (the X). Toledo describes AC grade as common for interior applications where appearance matters, such as furniture, cabinets and wall paneling, with an A face that is smooth, well sanded and has minimal defects. APA's A-C is Exterior-bond only, with one appearance face, and is used for soffits and fences. It is the step up from CDX when you want a face you can paint or finish.

Pros

• A smooth, sanded face with few defects, so it paints well and can take clear coats.
• Exterior bond. APA calls A-C Exterior only, built for weather exposure with a fully waterproof bond.
• Cheaper than birch or oak plywood. Toledo's 3/4 in AC radiata is $54.95.
• Rated and stamped to PS 1.
• Available in a wide range of thicknesses from 1/4 to 3/4 in.

Cons

• The back is C grade, with patches and open defects, so only one side is attractive.
• Core gaps allowed in the inner plies, so edges can be rough or void-filled.
• Softwood face dents and blotches; stain gives uneven results.
• A 23/32 in sheet sold as "3/4 in" is thinner than nominal, as with Dunn's Arauco ACX.
• Prices vary: Dunn's 3/4 in Arauco ACX is $77.88, over $20 more than Toledo's AC radiata.

Variants and subspecies

• A-C Exterior (APA): one appearance face, Exterior bond; soffits, fences.
• ACX vs AC: the "X" marks exterior-type glue; AC is the grade on the face and back. Sellers use both.
• Radiata AC: Toledo sells AC plywood in radiata pine; see Arauco and radiata pine plywood and Radiata pine.
• Southern pine and Douglas-fir ACX: depends on mill; see Southern yellow pine and Douglas fir.
• A-D and B-C: see Sanded pine plywood.
• CDX: rough, structural; see CDX sheathing plywood.

Working and finishing

Cut with a fine-tooth blade, A face up for a hand saw. Fill and sand edges, or cover them with edge banding. Prime knots and patches. Seal edges before outdoor use, and prime and paint all faces. Screws hold well in the face; pre-drill at the edge.

Staining and finishing colour

Softwood veneer blotches under stain. Gel stain or conditioner helps; paint is more reliable. A clear finish accentuates grain and patches. Sanding through the thin A face reveals the plies below, so keep sanding light.

Sustainability and handling

Exterior structural-type plywood is excluded from the EPA TSCA Title VI formaldehyde rule (EPA FAQ, checked 2026-09-30), and Columbia Forest Products says PF is the glue in exterior structural softwood plywood. Dust is irritating when cut or sanded. Sheets are heavy. Store flat and keep the edges dry.

Popular projects

Soffits and fences, sheds, planters and boxes, painted cabinets and shelves, and shop furniture. Under tile, check the product rating before using it as an underlayment.

Buying notes

Buy flat, patch-free A faces. Check the actual thickness; Dunn Lumber lists Arauco ACX 3/4 in as net 23/32 in at $77.88. Toledo AC radiata (September 2026): 1/2 in $45.95, 5/8 in $49.95, 3/4 in $54.95, 1 in $83.95. Compare mills before committing, since price spreads are wide.