Specifying Insulation for Flat Roof Car Park Decks

Multi-storey car parks are an essential part of every modern city. While they seem like simple constructions, a well-built, safe, clean and long-lasting car park requires particular materials and design approaches. A key part of this is preventing water ingress through the car park deck, which can lead to damp, cracked, spalling concrete, slippery floors and damaging alkaline salts dripping onto car paintwork. Good design, including using the right insulation materials, is key to ensuring a car park is well constructed.

Car Park Deck Design

A car park deck is essentially a type of warm flat roof. In a warm roof construction, the insulation layer is installed above the structural deck and below the waterproofing layer. A car park deck is a warm roof where the imposed loads from vehicle weights are significant, meaning the design requires an insulation material capable of bearing heavy loads while maintaining its integrity. 

Extruded polystyrene (XPS) foam has a number of key characteristics that make it ideal for car park decks, including superior load-bearing performance, water repelling qualities and a flat, strong and dimensionally stable base for the deck overlay. In many car park deck constructions, the insulation layer is covered by a separating layer, screed and mastic asphalt or liquid-applied waterproofing. 

Benefits of XPS Foam in Car Park Decks

XPS foam has a high compressive strength for specialist applications such as car park decks, heavy duty flooring and inverted roofing. It also resists water absorption and provides excellent thermal performance. Other benefits include:

• XPS foam boards have a high strength-to-weight ratio, making them robust and highly durable while at the same time lightweight and easy to transport.

• XPS foam boards are long-lasting with a service life comparable with that of a car park, building or structure.
• XPS foam is durable enough to withstand the stress of heavy surface traffic and mechanical damage that may occur during installation and maintenance.

If the waterproofing layer is damaged in a car park deck, the XPS foam won’t be damaged by exposure to moisture or water. An important part of flat roof designs are the detailing and construction of suitable upstands around the roof edge. XPS foam boards limit heat loss due to thermal bridging where the flat roof joins with the external wall. 

Meeting Car Park Deck Load Requirements With XPS Foam 

The closed-cell structure of XPS foam gives it excellent load-bearing qualities. The material is extremely rigid and capable of withstanding both static and dynamic compression. Technonicol’s Carbon Prof 300 XPS foam offers a minimum compressive strength of 300 kPa and 500 kPa with Carbon Solid 500 XPS foam. This makes these XPS foam boards appropriate for car park decks

Technonicol XPS Foam – Ideal for Car Park Decks

Technonicol’s Carbon XPS foam insulation series comes in a variety of sizes, thicknesses and compressive strengths to meet the demands of almost every application, including car park decks.