Marine Trade Supplies has been stocking Thermo-Lite Board for about ten years — a closed-cell composite sheet that trades use every week for floors, transoms, stringers and other structural cores that must not rot. Sheets are on the rack in the Coomera store and available through the online shop.
Thermo-Lite Board is made by Constructive Composites Australia (CCA Boards) in Queensland. It is a lightweight composite of cross-linked polymer foam and fibreglass: non-absorbent, dimensionally stable, tough under load, and a good bonding surface for adhesives, resins, gelcoats and paints. In the marine trade it is the go-to replacement when marine plywood has soaked and failed as a core.
What’s in the range
We sell full sheets only, sanded both sides, in the common boat-building sizes:
- Sheet size — 1220 mm × 2440 mm
- Thicknesses we stock — from about 6.35 mm through to 25 mm (CCA manufactures a wider thickness range)
- Finish — sand / sand, ready for glue, resin or paint
On the rack the sheets are listed as T/Board or S/Board depending on the line. We mainly sell 19 mm for transoms; for floors, many jobs use 12.7 mm where supports are close, stepping up to 15 mm or 17 mm for heavier loads. CCA quotes a density band of about 320–640 kg/m³ depending on the product line.
Thermo-Lite Board — closed-cell polymer foam and fibreglass composite
Floor, stringers and transom core in Thermo-Lite — Kingfisher Cruisers rebuild at The Boat Works (photos courtesy Kingfisher Cruisers)
Why trades choose Thermo-Lite
Unlike plywood, Thermo-Lite will not absorb water and will not rot — CCA and our own product notes put it as essentially waterproof in the core. It is lighter than an equivalent sheet of plywood on many jobs, cuts with a handsaw or jigsaw, and takes structural epoxy or vinylester with cabosil cleanly. Common marine uses include flooring, bulkheads, stringers, hatch covers, motor mounts and transoms.
One caveat from our product page: it is not UV-stable, so finish it (paint, resin, carpet or laminate) if sunlight can reach the sheet. For transoms, many builders laminate sheets to build thickness and check in stainless plate where ski hooks or outboard mounts land, so loads are spread and mounts do not compress the core.
Structural repairs are not DIY advice from us — we are a chandlery, not licensed boat builders. For a major floor or transom rebuild, talk to a marine surveyor or qualified boat builder first. We are happy to supply the sheet and the epoxy once the plan is clear.
Shop Thermo-Lite Board online
A few sheets from the current range:
- Thermo-Lite 6.35 mm sheet (1220 × 2440, sand/sand)
- Thermo-Lite 9.5 mm sheet (1220 × 2440, sand/sand)
- Thermo-Lite 12.7 mm sheet (1220 × 2440, sand/sand)
- Thermo-Lite 19 mm sheet (1220 × 2440, sand/sand) — popular for transoms
Need a thickness tip or a matching structural epoxy for the job? Call us on 07 5500 0002 or drop into the store at The Boat Works, Coomera — happy to point you at the right sheet.