EXPOL Retaining Wall Solutions — Drainage, Insulation & Membrane Protection
EXPOL provides a complete range of retaining wall solutions designed to protect waterproofing membranes, improve drainage performance, and support the long-term durability of concrete, block and timber retaining walls. Using lightweight, high-quality EPS and XPS products, these systems help manage groundwater, reduce lateral pressure and offer practical, long-lasting performance suited to New Zealand site conditions.
ThermaSlab, EXPOL-X, StyroDrain and QuickDrain provide versatile options for membrane protection, insulation and drainage.
ThermaSlab offers a protective layer when gravel or scoria backfill is used, while EXPOL-X delivers high-compressive strength exterior insulation with superior water resistance.
StyroDrain — manufactured from 100% recycled polystyrene — provides a cost-effective drainage sheet system for limited-access or environmentally sensitive sites, and QuickDrain offers a no-scoria drainage solution, ideal as a standalone system or used together with StyroDrain for integrated groundwater management.
Manufactured using durable EPS and XPS materials — many containing recycled content — EXPOL retaining wall products resist moisture, retain their thermal and mechanical performance, and can be recycled at end-of-life through EXPOL's nationwide recycling programme.
Retaining Walls - Product Range
Click a product below to view full technical details and installation information
Installation & System Components
EXPOL ThermaSlab S (EPS – Expanded Polystyrene)
EXPOL ThermaSlab should be placed hard up against the retaining wall after the water proofing membrane or tanking has been applied. EXPOL ThermaSlab should be held in place while the drainage material is added. EXPOL supplies a construction adhesive, Styro-FIX for this purpose.
The sheets of ThermaSlab are used to give protection to the water proofing membrane or tanking on the retaining wall. This is important so the drainage material (scoria) does not damage the membrane. EXPOL Thermaslab should cover all waterproofing membrane and tanking. The sheets of EXPOL ThermaSlab should not be exposed at the top of the wall.
Key Benefits
Why choose EXPOL Retaining Wall Solutions for your project
Membrane Protection
Offers membrane protection in addition to drainage and insulation
Drainage Solution
Effective water management and drainage behind retaining walls
Versatile Applications
Suitable for concrete, block, and wooden retaining walls
Insulation Properties
Provides thermal insulation in addition to protection and drainage