Concrete Forming & Rustication Plastics

Plastics for Concrete Forming

Core Concrete Forming Materials

Concrete Forming & Rustication Plastics FAQ

What are concrete rustication strips?

Rustication strips, also called reveal strips, attach to the form face to create controlled grooves, shadow lines, and architectural reveals in cured concrete. Plastic strips made from HDPE or UHMW resist moisture and can be reused for multiple pours when properly handled.

Does concrete stick to plastic forms?

Plastics like HDPE and UHMW feature a low-surface-energy, low-friction finish that helps reduce adhesion and improve release. While a light form release agent is still often used for best practices, stripping plastic forms is significantly easier and cleaner than stripping wood forms.

Can plastic sheets replace MDO/HDO plywood?

HDPE or UHMW sheet can be used as a nonabsorbent form face or liner in some tilt-up and precast applications, but neither is a direct structural substitute for MDO/HDO plywood. Plastic has different stiffness and thermal expansion, and it can creep under sustained load. The form may need continuous backing, a different fastening pattern, and clearance for expansion. Finish quality depends on the sheet surface and joints as well as the release agent, concrete mix, and placement.

How many times can you reuse plastic concrete forms?

When properly maintained, plastic form liners, chamfers, and rustication strips made from HDPE or UHMW can often be reused for multiple pours. This can lower the cost per pour compared to traditional wood forms, which can degrade, warp, or splinter after only a few uses.

What is the difference between HDPE and UHMW for concrete forming?

Both plastics offer excellent concrete release properties and very low moisture absorption. HDPE is generally more cost-effective and easier to fabricate, making it the common material choice for form liners and rustication strips. UHMW features a higher molecular weight and has extreme abrasion resistance, making it the premium choice for high-wear precast plants, chutes, or moving slip forms.

How do you attach plastic rustication strips to the formwork?

Polyethylene's low surface energy makes it difficult to bond with general-purpose adhesives. Rustication strips are commonly secured to plywood with nails, brads, or screws, while proprietary clip systems, compatible tapes, or specialty adhesives may be used when specified.

Can I cut or route plastic form materials on the job site?

Yes. Plastics like HDPE, UHMW, Polypropylene, and PVC are highly machinable. Contractors can easily cut, drill, and route these materials on-site using standard woodworking tools equipped with carbide-tipped blades.

How do you clean cured concrete off plastic forms?

Concrete does not chemically bond well to plastics like HDPE and UHMW, making cleaning much easier than with wood forms. Clean plastic forms after each pour before residue fully hardens whenever possible. For cured buildup, use a plastic scraper or stiff-bristled nonmetallic brush, then wash away loose residue with water and mild detergent. Avoid sharp metal tools that can gouge the surface. Use pressure washing or chemical concrete removers only when permitted by the form or liner manufacturer.