Polystyrene Insulation

Polystyrene insulation is a rigid foam board insulation widely used across UK construction for its combination of thermal performance, compressive strength, and competitive cost. One of the longest-established insulation materials in the industry, it remains a trusted choice across both new build and retrofit projects. Lightweight and easy to work with on site, it is a practical choice for a broad range of applications and performs reliably in environments where moisture resistance is a key consideration.

Types of Polystyrene Insulation

Polystyrene insulation is available in two distinct forms, expanded (EPS) and extruded (XPS), each suited to different performance requirements and applications.

Expanded Polystyrene (EPS) Insulation Boards

EPS boards are a lightweight, cost-effective rigid insulation option with good thermal performance and solid moisture resistance, making them one of the most widely used polystyrene insulation boards in UK construction. Available in a range of grades to suit different compressive strength and application requirements, you can browse our full range on our dedicated EPS insulation page.

Extruded Polystyrene (XPS) Insulation Boards

XPS boards offer greater compressive strength and superior long-term moisture resistance compared to EPS, making them the preferred choice for below-ground, inverted roof, and high-moisture applications. You can browse our full XPS offering on our dedicated XPS insulation page.

Applications for Polystyrene Insulation

Polystyrene insulation boards are most commonly used in floor applications, and for good reason. Their compressive strength, moisture resistance, and competitive price point make them a natural fit for ground floors, below-screed installations, and below-slab build-ups in both domestic and commercial projects. Compared to other rigid board types, polystyrene also offers a practical advantage on site, being lightweight, easy to cut, and straightforward to lay, which helps keep installation time and labour costs down.

EPS grades are widely specified for standard residential floor slabs, while XPS boards are the preferred choice where greater load-bearing capacity or prolonged moisture exposure is a factor. Beyond floors, polystyrene insulation boards are also used in external wall insulation base layers, flat and pitched roof build-ups, and below-ground basement applications across both new build and refurbishment projects.

Why Choose Insulation UK for Polystyrene Insulation?

A Comprehensive Range of polystyrene insulation boards in stock across EPS and XPS, in a wide range of thicknesses and grades.

EPS and XPS from Leading Manufacturers including Jablite, Kingspan GreenGuard, and Ravatherm, all available at competitive trade prices with no minimum order value.

Fast UK-Wide Delivery with free shipping on orders over £500 (ex VAT), and reliable nationwide logistics on every order.

Wide Range of Thicknesses available from 13mm through to 75mm and above, covering everything from shallow floor build-ups to below-ground and high-performance applications.

Competitive Pricing with some of the lowest polystyrene insulation prices available online, backed by strong stock availability and a trusted supply chain.

Expert Help and Advice from a team with over 50 years in the industry. Whether you're specifying the right EPS grade for a commercial floor slab or selecting XPS for a challenging below-ground application, we're here to ensure your project runs smoothly from start to finish.