Sign material

MDO Plywood

Exterior plywood with a resin impregnated paper face. The traditional billboard and construction sign material, and still the right answer for big and temporary.

Also called	Medium density overlay, signboard plywood
Thicknesses	3/8 in, 1/2 in and 3/4 in, in standard 4 x 8 sheets.
Weight	Heavy. A 3/4 in 4 x 8 sheet runs well over 60 lb, which decides your framing and your install crew.
Outdoor life	Several years painted and properly sealed. It is wood, so it lives or dies by whether the edges were sealed.
Ballpark cost	Roughly 70 to 120 dollars a sheet depending on thickness and whether one or both faces are overlaid.

Ballpark trade prices for a 4 x 8 sheet as of August 2026, before markup. Yours will differ by supplier, region and how much you buy at once — treat these as a sanity check on a quote, not a price list.

What it actually is

Exterior grade plywood with a resin treated fibre overlay fused to one or both faces. The overlay hides the grain and gives paint and vinyl a proper surface.

What it is good for

→ Construction site and development signs
→ Billboard and large format temporary panels
→ Real estate signs on posts where size matters more than weight
→ Painted signs in a traditional style

What to watch for

Unsealed edges are how every MDO sign fails. Water wicks into the ply, the layers delaminate and the face bubbles. Seal every cut edge, including the holes.

It is heavy enough to change the engineering. A 4 x 8 in 3/4 in on two posts needs real posts and real footings, not what you would use for Coroplast.

The overlay is the printing surface. Sand through it and you are painting bare plywood, which will telegraph grain within a season.

It will bow if stored leaning. Store flat, like every sheet good in the shop.

Printing and finishing

Made for paint and vinyl rather than direct printing. Prime the overlay first for painted work, and most shops apply printed vinyl rather than trying to run a sheet this heavy through a flatbed.

Pricing a MDO Plywood job?

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MDO Plywood — FAQ

What does MDO stand for?

Medium density overlay. It refers to the resin impregnated paper layer bonded to the plywood face, which is what makes it a sign material rather than just plywood.

How long does an MDO sign last outside?

Several years if it is painted and every edge is sealed, and one wet season if the edges were left bare. The sealing is not optional.

MDO or ACM for a construction sign?

MDO for the big temporary panel that gets built into a frame on site, because it is cheaper by the square foot at 4 x 8 and up. ACM once it needs to look permanent or stay up for years.

Your materials, priced once

Set your substrates, vinyls and laminates up once in PrinterFlo and every quote prices itself by size and options, with cost, profit and margin on the line as you build it.

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