The Best Weed Barrier for a Flagstone Patio

Best Barrier

• The best weed barrier for a flagstone patio is a professional-grade plastic barrier. Unlike fabric barriers, which allow air to penetrate for natural soil aeration and grass growth, plastic barriers seal off plants and soil from the sun and rainfall. According to landscaping professionals at The Landscape Design Site, this effectively kills all plant life below the barrier. Heavy-duty professional barriers are thicker and more durable than inexpensive plastic sheeting; these qualities allow them to last for many years below a flagstone patio.

Function

• The primary function of a flagstone patio's weed barrier is to prevent weeds and grass from growing up through cracks in individual stones or between gaps in the mortar that holds the stones together. Flagstone pavers are expensive to purchase and install, which makes it especially important to protect them from damage due to weeds. An effective weed barrier will allow the flagstone surface to remain flat and free from cracks. Without a functional barrier, weed growth may require expensive flagstone removal and replacement.

Installation

• Weed barriers physically prevent weeds from penetrating the surface or receiving heat and light energy from the sun. You can roll out a barrier over the graded soil where the flagstone patio will be. This creates a clean, even base for laying the stones and mortar. Some barriers include chemicals that slow or stop weed growth. Landscapers can also apply conventional weed killer to the soil to destroy any germinating weeds before laying the barrier.

Environmental Considerations

• While heavy plastic weed barriers are best for protecting your flagstone patio, they are not the best or most environmentally sustainable solution for other applications. Woven geofabric barriers are made from natural materials and promote the growth of other plants by suppressing weeds. If your flagstone patio includes openings for plants, a plastic barrier will make it difficult to grow them in the ground directly. Instead you can consider a fabric barrier that places your patio at some risk of weed growth, or decorate with potted plants and use a plastic weed barrier below the entire patio.