Plywood grades, board selection and timber notes for real jobs

BuildEx Plywood is a working notebook for builders, shopfitters and DIY woodworkers across South Africa. We compare marine, structural and shuttering sheets, look at WBP versus interior glue lines, check voids and sanding grades, and work through cutting plans for a 2440 x 1220 board. If a sheet delaminates on site or a cut list gets tight, that is the kind of thing we write up next.

Read the board notes Send a photo or cut list

Start with the grade comparison in marine versus structural ply, or go straight to the workshop contact page.

Send in the sheet that failed, or the cut list that will not fit

A photo of a delaminating edge, a warped panel after a wet week, or a cutting plan that keeps running short on a 2440 x 1220 sheet is more useful than a general question. Send it through and it gets worked through properly, with the grade, glue line and thickness notes that apply.

Trade names only when suppliers come up. No paid placement, no hidden recommendations.

Send your sheet or cut list

info@buildexplywood.com

027-448-6750

Not ready to send anything yet? Browse the notebook or start with marine vs structural ply .

Questions that come up before a sheet gets cut

Short answers to the things builders, shopfitters and home woodworkers ask most often when they are standing in a yard or staring at a cut list.

How do I tell marine ply from structural ply on the rack?

Look at the edge, not the face. Marine sheets should show tight, even veneers with almost no gaps between plies, and the glue line reads dark and continuous. Structural ply can carry small voids and still do its job in a dry frame, but once it sits in a wet deck or a van floor, those gaps are where water starts working.

Is WBP glue always worth the extra cost?

Only where the board will actually see moisture. For kitchen carcasses, wardrobe internals and shelving inside a dry house, an interior-bonded sheet is fine. WBP earns its place on bathroom vanities, exterior door skins, boat fit-outs and anything that lives near the coast.

What thickness should I spec for shelving and carcasses?

For a shelf run under 900 mm with light loads, 18 mm is the usual starting point. Longer spans or heavy loads want either 25 mm or a stiffener glued underneath. Kitchen carcasses are almost always 16 to 18 mm, with the back panel doing most of the racking resistance.

Why does my board cup after a week in the workshop?

Moisture moves through the edges faster than the faces. A sheet stored flat on a concrete floor in Durban will pick up water from below, while the same sheet in a dry Highveld winter dries out and shrinks. Seal the edges, keep sheets on bearers, and let the board acclimatise before you cut.

Can I use shuttering ply for permanent work?

It is built to survive a few pours, not a decade. The face is often patched and the glue line is not rated for long-term exposure. Fine for formwork, sub-frames that stay covered, and temporary jigs. Not what you want on a visible cabinet or a deck that gets rained on.

How do I get more usable parts out of one 2440 x 1220 sheet?

Draw the layout before the first cut, allow for blade kerf, and keep offcuts in standard sizes so they can be reused. Grain direction on visible faces often decides the plan more than raw yield does. A quick pencil sketch on the sheet saves more board than any clever jig.

Still weighing up a grade for a specific job? The questions page collects the longer answers, and you can send a photo of a delaminating sheet or a tricky cut list through the contact page.

Why builders keep this notebook open on the bench

There is no shortage of plywood advice online, and most of it was written for a market that is not ours. A sheet that behaves in a European workshop can cup in a Durban summer and crack in a Free State winter. Everything here is written from South African site conditions, local supplier stock and the sizes that actually arrive on the bakkie.

Grade calls, not grade lists

A spec sheet will tell you a board is WBP bonded. It will not tell you whether your kitchen carcass needs it. We work through the job first, then the grade, then the thickness, in that order.

Supplier names, no placements

Yards in Gauteng, KZN and the Western Cape get mentioned by trade name because that is how builders talk to each other. Nobody pays to appear here, and a bad batch gets called out the same as a good one.

Your photos, worked through

Send a shot of a delaminating edge or a cut list that will not nest. If it raises a question other readers will hit too, it gets pulled apart in the next post with the numbers shown.

How this differs from a supplier catalogue

Catalogues sell what is in the yard this week. We start from the build: shelving spans, van floor ribs, formwork that only has to survive three pours. That usually changes the answer, and sometimes it means buying the cheaper sheet.

Where the trust comes from

Void checks on the edge, moisture readings before machining, offcut sizes kept reusable. The notes are specific enough to argue with, which is the point. If a method fails on your site, that is worth writing in.

Start with the grade comparison in Marine vs Structural Ply, or send a photo and a cut list through the contact page.