For decades, the standard approach was to lay terrace pavers directly on wet mortar or an aggregate subbase. Today, designers are increasingly choosing raised deck terrace systems built on adjustable pedestals.
What Is a Raised Terrace System?
A raised terrace elevates pavers, tiles, or decking boards above the structural substrate using heavy-duty support posts called adjustable pedestals. Instead of bonding materials directly to a slab with cement or adhesive, pavers rest dry on top of these pedestals. Open joints between the tiles allow rainwater to drain straight through into the cavity below.
As a manufacturer of adjustable pedestals, we see firsthand how this simple shift in installation mechanics solves long-standing challenges in outdoor construction.
Key differences: pedestal systems vs. mortar-based construction
Both construction methods create attractive outdoor spaces, but they handle moisture, maintenance, and structural loads in fundamentally different ways.
- Drainage mechanism: Raised pedestal systems feature open joints between pavers that allow rainwater to drain immediately into the void beneath the deck. Traditional mortar beds rely on surface slopes directing runoff to perimeter drains or gutters, which can leave moisture on the pavers.
- Sub-surface access: With an adjustable pedestal system, individual pavers can be easily lifted for quick inspection or repair. In contrast, traditional mortar construction requires partial demolition of the tiles and substrate to reach hidden utilities or waterproofing membranes.
- Thermal expansion: Unbonded pavers on pedestals adjust independently with weather changes, preventing joint cracking. Rigid joints in mortar systems often crack when temperature fluctuations cause the concrete substrate to expand and contract.
- Structural weight: Dry pedestal installations completely eliminate heavy layers of wet mortar. Traditional wet mortar beds add significant dead weight to the building envelope, which can be a serious limitation in raised or rooftop projects.
- Weather dependency: Pedestal systems can be installed in various temperatures without waiting for curing. Mortar projects require dry weather and specific temperature ranges during application and curing, making them more susceptible to rain-related delays.
See also: SPIRAL pedestal 70-90 mm with D3 for tiles
See also: Clever Level 80-200 mm pedestal, 3 mm for tiles & decking
1. Excellent water management
Standing water is the main cause of damage to outdoor tiles. When water accumulates on a mortar-bonded surface, low temperatures can freeze this moisture, causing tiles to detach from the substrate. Raised systems completely eliminate water accumulation on the surface. Water drains into the empty space underneath, where waterproofing with a slope to the drain safely carries it away.
2. Hidden installations and easy maintenance
Raising the level of the terrace creates a functional space beneath it. Contractors use this void to hide irrigation lines, electrical cables, architectural lighting and drainage pipes. If a pipe leaks or a cable needs replacing, technicians lift the specific paver above it, carry out the repair and lay the paver back down. Mortar-based systems require the use of pneumatic hammers to solve similar problems.
Understanding cost factors
Assessing the total cost requires looking beyond initial material estimates to account for labor efficiency and long-term maintenance.
Initial material costs
- Mortar bed: Sand, cement, grout, bonding agents and terrace pavers. Material costs per square metre are often lower initially.
- Raised systems: Terrace pavers and specially designed pedestals and specialist accessories (such as slope correctors or spacer clips).
Labor and installation time
- Cementitious substrate: Very labor-intensive. Installers must prepare mortar, lay the substrate layers, manually level the tiles and fill the grout joints. The process requires several days of curing before the surface can be walked on, which exposes the schedule to rain-related delays.
- Raised systems: Faster installation. Installers set the pedestals, adjust the height and slope, and then lay the pavers dry. No mixing and no curing means fewer labor hours on site and lower costs of weather-related downtime.
Long-term maintenance and durability
Traditional masonry terraces often require re-grouting of joints, replacement of tiles due to frost damage, and costly membrane repairs over their service life. Raised systems reduce these recurring costs because the terrace pavers are not bonded and are resistant to substrate movement.
Is a raised deck terrace a good solution for your project?
While raised systems offer clear benefits for roof terraces, balconies and uneven substrates, traditional mortar beds still work well for simple ground-level patios on solid concrete slabs without the need for substrate drainage.
When designing a project involving waterproofing membranes, slope correction, integrated installations or tight deadlines, an adjustable terrace pedestal system provides a clean and durable alternative solution. When specifying terrace pedestals, choose products designed for high load capacity, UV stability and precise slope correction to ensure a stable terrace surface for decades to come.
