Should You Remove Old Plastic Sheeting And Gravel Under Your Deck A Comprehensive Guide

Replacing a deck is a significant home improvement project, and it's crucial to get every detail right for long-term stability and aesthetics. One common question that arises during deck replacement is whether to remove the old plastic sheeting and gravel underneath the existing structure. This article delves into the pros and cons of removing these materials, providing you with the information you need to make an informed decision. We'll explore why these materials are initially installed, the potential problems they can cause if left in place, and best practices for preparing the sub-deck area for your new deck. So, let's dive in and ensure your new deck stands the test of time!

Understanding the Role of Plastic Sheeting and Gravel Under Decks

Before we get into the nitty-gritty of removal, it's essential to understand why plastic sheeting and gravel are often installed under decks in the first place. Plastic sheeting and gravel serve several purposes, primarily related to moisture control and weed prevention. Let's break down each of these functions:

Moisture Barrier

The primary reason for using plastic sheeting is to act as a moisture barrier. Guys, think about it: the ground beneath a deck can be a breeding ground for moisture, especially in areas with high rainfall or humidity. This moisture can evaporate and rise, potentially causing several problems for your deck structure. Excess moisture can lead to wood rot, decay, and even attract pests like termites. By placing a layer of plastic sheeting on the ground, you create a barrier that helps to prevent moisture from reaching the wooden components of your deck. This is crucial for extending the lifespan of your deck and preventing costly repairs down the road. The plastic sheeting essentially acts as a raincoat for the soil, keeping the moisture where it belongs – in the ground.

Weed Control

Another significant benefit of using plastic sheeting and gravel is weed control. Weeds growing under your deck aren't just an eyesore; they can also contribute to moisture retention and create an environment conducive to pests. Gravel acts as a physical barrier, making it difficult for weeds to sprout and grow. The plastic sheeting underneath the gravel further enhances this weed control by blocking sunlight, which is essential for plant growth. Together, these materials create a formidable barrier against unwanted vegetation, keeping the area under your deck clean and tidy. This is especially important for maintaining the aesthetics of your outdoor space and preventing weeds from potentially damaging the deck structure over time.

Drainage Enhancement

While plastic sheeting primarily acts as a barrier, gravel plays a crucial role in drainage. Gravel helps to improve drainage by allowing water to flow away from the deck's foundation. This is particularly important in areas with poor soil drainage. If water tends to pool under your deck, it can create a damp environment that encourages rot and decay. The gravel layer provides a pathway for water to escape, reducing the risk of moisture-related problems. This combination of plastic sheeting and gravel works synergistically to manage moisture levels under the deck, ensuring a healthier and longer-lasting structure.

The Case for Removing Old Plastic Sheeting and Gravel

Now that we understand the initial purpose of plastic sheeting and gravel, let's explore why removing these materials during a deck replacement might be a good idea. While they serve a beneficial function when properly installed, old plastic sheeting and gravel can sometimes create more problems than they solve. Here’s a detailed look at the reasons why removal should be considered:

Degradation and Ineffectiveness Over Time

One of the primary reasons to remove old plastic sheeting and gravel is that these materials degrade over time. Plastic sheeting, especially if it's been exposed to the elements for years, can become brittle and tear. Once the plastic is compromised, it loses its ability to effectively block moisture and prevent weed growth. Similarly, the gravel layer can become compacted and mixed with soil, reducing its drainage capabilities. This degradation means that the original benefits of these materials are diminished, and they may no longer be providing adequate protection for your deck. Removing the old, ineffective materials allows you to start fresh with a new system that will function optimally.

Potential for Trapped Moisture

Ironically, old plastic sheeting can sometimes trap moisture rather than prevent it. If the plastic is torn or improperly installed, water can seep underneath it and become trapped. This creates a damp environment that is ideal for mold and mildew growth, which can damage the wooden components of your deck. Trapped moisture can also accelerate wood rot and attract pests, leading to structural problems. By removing the old plastic, you eliminate the risk of creating a moisture trap and ensure that the area under your deck remains dry and well-ventilated. This is a crucial step in preventing long-term damage to your new deck.

Harboring Pests and Debris

Over time, the space under your deck can become a collection point for debris, such as leaves, twigs, and other organic matter. This debris, combined with the damp environment created by old plastic sheeting, can create an ideal habitat for pests like insects, rodents, and even snakes. The gravel layer can also provide hiding places for these creatures. Removing the old materials allows you to clean the area thoroughly, eliminating potential pest infestations and creating a healthier environment under your deck. This is particularly important for homeowners who want to maintain a clean and pest-free outdoor space.

Facilitating Proper Sub-Deck Preparation

Removing the old plastic sheeting and gravel is essential for proper sub-deck preparation. Before installing your new deck, it’s crucial to ensure that the underlying area is level, stable, and free of any obstructions. Old materials can interfere with this process, making it difficult to create a solid foundation for your new structure. Removing the old layers allows you to properly grade the soil, add new materials as needed, and ensure that your new deck is built on a stable base. This thorough preparation is key to the longevity and stability of your deck.

Arguments Against Removal: When It Might Be Okay to Leave It

Despite the compelling reasons to remove old plastic sheeting and gravel, there are situations where it might be acceptable to leave these materials in place. It’s essential to evaluate the specific conditions under your deck and weigh the potential benefits against the risks. Here are some scenarios where leaving the old materials might be considered:

Intact and Functioning System

If the existing plastic sheeting and gravel system is in good condition and functioning effectively, removal might not be necessary. For example, if the plastic is still intact, the gravel is clean and well-draining, and there are no signs of moisture problems or pest infestations, leaving the materials in place could save you time and effort. However, it's crucial to thoroughly inspect the area to ensure that the system is truly in good shape. Look for tears in the plastic, compaction in the gravel, and any signs of moisture or pest activity. If everything checks out, you might be able to leave the materials undisturbed.

Minimal Disturbance to the Soil

In some cases, removing the old materials could cause more harm than good by disturbing the soil and potentially affecting nearby landscaping. If you have mature trees or plants close to your deck, aggressive removal efforts could damage their root systems. In such situations, it might be better to leave the materials in place and focus on adding a new layer of protection on top. This approach minimizes soil disturbance and protects your existing landscaping. However, you'll still need to ensure that the new layer of protection is properly installed and will effectively address moisture and weed control.

Contractor's Recommendation and Experience

Your contractor's recommendation should also play a significant role in your decision. Experienced contractors have likely encountered similar situations and can provide valuable insights based on their expertise. If your contractor advises against removal, be sure to ask for a detailed explanation of their reasoning. They may have observed specific conditions under your deck that make removal unnecessary or even detrimental. However, it’s always a good idea to get a second opinion if you’re unsure, ensuring you’re making the best decision for your deck.

Best Practices for Sub-Deck Preparation

Whether you choose to remove the old plastic sheeting and gravel or not, proper sub-deck preparation is essential for the success of your deck replacement project. Here are some best practices to follow:

Thorough Inspection

Start with a thorough inspection of the area under your deck. Look for signs of moisture damage, pest infestations, weed growth, and any other potential problems. Assess the condition of the existing plastic sheeting and gravel, if present. This inspection will help you determine the best course of action for sub-deck preparation.

Removal of Debris and Vegetation

Regardless of whether you remove the old materials, clear the area of any debris, vegetation, and other obstructions. This will create a clean and level surface for your new deck. Remove any weeds or plants growing under the deck, and clear away any accumulated leaves, twigs, and other organic matter.

Grading and Leveling the Soil

Ensure that the soil is properly graded and leveled to promote drainage and prevent water from pooling under the deck. This step is crucial for maintaining a dry and healthy environment under your deck. If necessary, add soil or gravel to create a gentle slope away from the deck's foundation.

Adding New Landscape Fabric and Gravel

If you choose to remove the old materials, consider adding a new layer of landscape fabric and gravel. Landscape fabric provides an additional barrier against weed growth, while gravel improves drainage and helps to prevent moisture buildup. This combination offers excellent protection for your new deck.

Ensuring Proper Ventilation

Proper ventilation is essential for preventing moisture problems under your deck. Ensure that there is adequate airflow to keep the area dry and well-ventilated. This can be achieved by leaving gaps between deck boards and ensuring that there are no obstructions blocking airflow.

Making the Right Decision for Your Deck

Deciding whether to remove old plastic sheeting and gravel under your deck is a crucial step in the deck replacement process. By understanding the pros and cons of removal, evaluating the specific conditions under your deck, and following best practices for sub-deck preparation, you can make an informed decision that will ensure the longevity and stability of your new deck. Remember to consult with your contractor, consider your local climate and soil conditions, and prioritize a dry, well-ventilated space under your deck. With careful planning and execution, your new deck will be a beautiful and durable addition to your home for years to come.