Fine detail
Silicone captures crisper detail than polyurethane. Every micron of the pattern reads on every casting. Where the finish matters visually, silicone earns its cost.
TCI Construction · Materials
Silicones, polyurethanes, and when to reach for each.
The mould material is the single biggest decision on any concrete tooling job. Here's how we think about it, in language that keeps buyers, yard managers and architects on the same page.
The starting point
Two material families do almost everything.
Silicone and polyurethane between them cover more or less every concrete moulding application we see. Rubber and other legacy materials still exist, but for modern precast, GRC, cast-stone and decorative concrete work, the choice is silicone or polyurethane.
Both come in many grades. Both have places where they're clearly right, places where they're clearly wrong, and a middle zone where either would work. This page walks through the honest picture.
Silicone
Four things silicone is genuinely better at.
Undercuts
Silicone flexes past undercut geometry that would jam or tear a polyurethane tool. Cornices, coffered panels, three-dimensional ornament — silicone territory.
Aggressive mixes
Some GRC face-mixes, some heavily pigmented concretes, and some accelerated cure regimes degrade polyurethane faster than silicone. On unusual chemistry, silicone survives longer.
Heritage reproduction
Silicone from an original picks up weathering, tool marks and asymmetry that make the reproduction read as continuous with the survivors. Polyurethane loses those subtleties.
Polyurethane
Four things polyurethane is genuinely better at.
Cost per square metre
Polyurethane costs meaningfully less than silicone at the same size, all else equal. For jobs that don't need silicone's detail advantage, that saving is real.
Rough handling
Polyurethane takes yard abuse that would nick silicone. Vacuum-lifted, hosed with cold water, stacked outside, occasionally walked on. Polyurethane forgives it.
Long shallow reliefs
Board-marked timber, sawn-grain texture, shallow stone facing. Polyurethane holds these easily and outlasts silicone in the same application.
High pour count runs
On repeat programmes running hundreds of pours off the same tool with sensible handling, polyurethane often reaches higher pour counts than silicone on the same geometry.
The middle
Where the choice is genuinely a coin flip.
There's a wide middle where either material would give you a decent tool. Moderate relief, moderate pour count, moderate handling. If your job is in that middle, we default to polyurethane because the total cost usually works out lower.
But we'll say if we think silicone is quietly the better answer for a specific piece. Sometimes a job that looks moderate on paper has one small feature that pushes it into silicone's territory — a fine relief in one corner, or an aggressive pigment, or a very rough yard. The right material for the whole tool depends on that one detail.
The best way through the choice is a short conversation about what you're actually casting, in what mix, and how the yard treats tools. Ten minutes on the phone is usually enough to settle it.
Written spec, every tool
Every mould leaves with a paper record of what it's made of.
Every tool we ship comes with a two-page material spec sheet. It says which silicone or polyurethane grade the tool is cast in, what temperature range it's rated for, what release agents it's compatible with, and roughly how many pours you should expect at typical handling.
That sheet is designed to be handed straight to your architect, your specifier or your quality auditor. It's not marketing; it's the technical spec, and it stays valid for the life of the tool.
Where to read next
Related pages.
Processes
How the tool is made once the material is chosen — pattern, pour, backing frame, delivery.
Read moreGet in touch
Send us a photograph of the panel or the elevation.
One photograph tells us what surface you're chasing, and one line about the mix tells us what silicone or polyurethane will survive it.
Real people, a real workshop
You deal with the people who make it.
No call centre and no middlemen. When you contact TCI Construction, you speak to the team who design, build and check your mould.
- A real Warwickshire workshopUnit 15, Waterloo Park, Bidford-on-Avon, Alcester B50 4JG.
- Real people on the phoneCall the team on 01789 224228, Monday to Friday.
- The same team on every jobDesign, production and aftercare come from the people you see here.
- Part of TCI GroupFive specialist brands, one engineering team. Visit TCI Group.
Thomas LaneManaging Director
George PrestonDesign & Project Manager
Kelly BallingerHead of Partnerships
Jim AndertonProduction Manager
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