Custom Flagstone Patio Installation | Montgomery County, MD

At Rocha Construction, we specialize in high-quality flagstone patio installation throughout Potomac, Bethesda, Rockville, and all of Montgomery County, Maryland. Natural Pennsylvania flagstone creates a timeless outdoor space with rich color variation, durability, and slip resistance.

A professionally installed flagstone patio is more than just a backyard upgrade — it is a long-term investment in your home’s beauty and value. Proper base preparation, correct stone thickness, and expert placement are what separate an average patio from one that lasts decades.

There are two primary methods for building a flagstone patio. Below we explain both systems so you can understand which one fits your property best.

1. Flagstone Patio Installed on Reinforced Concrete

This is the most durable and long-lasting option for homeowners in Potomac and Bethesda. A reinforced concrete slab is poured first, and the flagstone is installed directly over the cured surface using professional bonding techniques.

We recommend a minimum 4-inch concrete base reinforced with wire mesh or fiberglass. Proper soil compaction and drainage preparation underneath are essential to prevent cracking or settlement.

For best performance in Maryland’s freeze–thaw climate, flagstone should be at least 1” to 1.5” thick. Thinner materials may crack over time. A properly built concrete-based flagstone patio offers maximum stability and minimal long-term maintenance.

While some contractors reduce thickness to lower costs, a strong foundation ensures your patio will remain level, secure, and beautiful for decades.

2. Natural Flagstone Patio on Compacted Gravel (Dry-Laid)

A dry-laid flagstone patio is installed over a compacted gravel and stone dust base. This method allows natural drainage and provides a slightly more flexible structure.

We typically install 3”–4” of compacted CR6 gravel depending on soil conditions. Each flagstone piece is hand-placed and leveled individually to create a tight, puzzle-like fit.

Because there is no concrete slab underneath, thicker and heavier flagstone is recommended for stability. Joints are filled with stone dust or polymeric sand depending on the desired appearance.

This style provides a more natural look and allows easier repairs if needed. Periodic maintenance may be required, but the rustic beauty of a dry-laid flagstone patio remains a popular choice.

If you are planning a new flagstone patio installation in Montgomery County, MD, our family-owned team is ready to help. We provide free estimates and expert guidance to ensure your patio is built correctly from the ground up.

Rocha Construction: (301) 717-8310

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It is NOT allowed to use our pictures without our written consent.