Ground floor – suspended floor decks

Ground floor – suspended floor decks

Suspended ground floor decks – for example, a block and beam floor, or precast concrete plank – are an efficient way of providing a level floor on plots with poor ground or steep slopes, where too much ground fill is required to pour a ground-bearing concrete slab.

With an inaccessible ventilated void underneath the deck, thermal insulation can only be positioned on top of it. A floating floor arrangement is the result, with a screed or board covering sitting on the insulation, ready to receive the chosen floor finish. A suspended floor deck therefore has some similarities to a ground floor with insulation installed above a concrete slab.

What Polyfoam XPS products are suitable for suspended ground floor decks?

Suspended ground floor decks are most likely to feature on domestic projects where the floor areas are comparatively small, and the most common solution of block and beam decks can span between supporting walls with ease, while achieving necessary ventilation flows.

Since the loads imposed by domestic use are relatively low, Polyfoam Floorboard Standard should provide ample performance for most situations. However, where larger domestic-type buildings perhaps use heavier screeds or impose slightly higher loads, Polyfoam Floorboard Extra offers the same thermal efficiency, and a higher compressive strength.

Polyfoam XPS Ltd is a leading manufacturer of closed cell, extruded polystyrene insulation. The Polyfoam range is lightweight, strong, moisture resistant and easy to cut and shape, providing thermal performance and strength for the lifetime of the building. Product benefits include:

  • High compressive strength and protects the damp proof membrane from damage.
  • Highly resistant to water absorption.
  • Robust and can tolerate traffic from following trades.
  • British Board of Agrément certificate.
  • Environmental Product Declaration.
  • BES 6001: Responsible Sourcing of Construction Products.

Why extruded polystyrene (XPS) insulation works well under a floating floor

The primary advantage of XPS insulation over other types of rigid board is its ability to resist moisture. By its nature, a suspended floor deck is not in contact with the ground, and that advantage is lost. So why is it worth still considering XPS as a solution?

Because XPS insulation boards provide a flat, strong and dimensionally stable base for the floating screed or flooring board – reducing the likelihood of defects in the floor covering or finish.

And, while they should be treated with the same care and attention as any other insulation product, their superior compressive strength means they offer that little bit more robustness when subjected to the rigours of a construction site.

Recommended Polyfoam XPS products for basement applications are: