Sub Bases For Patios

December 30, 2023

Building the Perfect Patio Base: A Comprehensive Guide

When planning an outdoor living space, understanding proper base construction is crucial for long-term durability and stability. This guide explores essential considerations for patio foundations, from material selection to installation techniques, helping you create a lasting outdoor space that withstands the test of time.

Do Patios Need a Base Layer?

While patios that will only experience foot traffic can sometimes function without a base layer, vehicle-bearing surfaces absolutely require one. The necessity depends largely on your chosen surface material and intended use. The base layer serves to spread loads and provide critical support - omit only with good reason after careful consideration of your specific needs.

Table 1: Base Guidelines by Surface Type
Surface Material	Base Required?	Minimum Base Depth	Notes
Concrete Pavers	Yes	4-6 inches	Essential for proper interlocking
Stamped Concrete	Optional	2-4 inches	Recommended for stability
Natural Stone	Yes	4-6 inches	Prevents settling and cracking
Porcelain Pavers	Yes	4-6 inches	Critical for preventing breakage
Brick Pavers	Yes	4-6 inches	Ensures even surface

What Thickness Should a Patio Sub Base Be?

For residential patios, a 4-6 inch base of packed gravel is typical. Driveways require at least 6 inches minimum depth, while commercial projects may exceed 9 inches base thickness. A general rule is to make base layers at least twice the maximum rock size to prevent pressure points.

Table 2: Recommended Base Depth
Application	Minimum Depth	Optimal Depth	Maximum Rock Size
Walkways	4 inches	6 inches	1.5 inches
Residential Patios	4-6 inches	8 inches	2 inches
Driveways	6 inches	8-10 inches	2.5 inches
Commercial Areas	8 inches	10-12 inches	3 inches

Can I Use Salvaged Materials as Base?

Base layers provide critical support, so durability matters. Scrimping with low-grade fill risks problems. The issue with repurposed masonry and concrete is random sizes/shapes and gaps. The same applies for "hardcore" rubble. Over time, backfill trickles into voids, allowing settling. Jagged pieces telegraph through, causing instability.

Avoid using whole bricks. Halved is better, but crushed masonry blended with clean gravel makes the best DIY base option. Topping this stabilized layer with 4-6 inches of road base stone completes a durable patio foundation able to withstand seasonal movement. Cutting corners on base build shortchanges overall longevity. Proper base materials make sound, long-term investments.

What Base is Ideal for Sandstone Pavers?

The optimal base for sandstone pavers is crushed stone or limestone, known for its compaction and high-traffic endurance. Sand is also favoured for its drainage capabilities and ability to provide a stable yet flexible foundation for natural stone materials.

Which Sub-Base Material is Best for Paving Slabs?

MOT Type 1, comprising crushed limestone, concrete, or granite without fines, is the preferred sub-base for paving slabs due to its superior quality and stability. This material offers excellent compaction properties and provides a solid foundation for various types of paving slabs.

What Sub-Base is Needed for a Porcelain Patio?

For a porcelain patio, a Type 1 MOT or General Sub-Base (GSB) aggregate is essential for providing strength and stability. It should be raked out to create an even layer, approximately 30mm below the string line to ensure proper leveling and support for the porcelain pavers.

What Should be Placed Under Porcelain Pavers?

According to best practices for porcelain pavers, a sand base is suitable for small patios or walkways over concrete or level ground, especially in dryer climates. This involves installing porcelain pavers over a compacted sand base to provide both stability and proper drainage while allowing for minor adjustments during installation.