Can You Lay New Blacktop Over an Existing Driveway?
The question of whether one can lay new blacktop over an existing driveway has been a topic of debate. The answer often depends on several factors including the condition of the existing driveway and the specific circumstances of the installation. In this article, we delve into the details of the process and provide key insights to help you make an informed decision.
When Is It Possible to Lay New Blacktop Over an Existing Driveway?
In many cases, it is possible to lay new blacktop over an existing driveway, but there are certain conditions that need to be met. If the existing asphalt surface is in good condition and has a sufficient base, then it can be resurfaced. However, if the existing surface is compromised, extra steps may be necessary to ensure a successful installation.
Proper Preparation for Replacing the Driveway
One of the most critical steps is to ensure that all existing pavement is ground or milled off the surface by at least 1 inch. This is crucial to remove any loose materials and to create a smooth surface for the new asphalt layer. If this step is not taken, the new blacktop may not adhere properly and can lead to failure.
Another important consideration is the base under the existing driveway. If the base is compromised, it is advisable to grind or mill down to a solid foundation. This ensures that the new layer of asphalt will have a stable support that can withstand the weight and traffic it will endure. Without a proper base, the new asphalt can crack and deteriorate quickly, leading to further repairs.
Handling the Unique Examples
Historical and unique examples highlight the potential risks associated with re-surfacing an existing driveway. In Portland, Oregon, the use of a blacktop coating on an old drawbridge over the Willamette River had a disastrous outcome. On a hot summer day after the installation, the bridge was lifted, and all the material slid off. This incident underscores the importance of careful consideration and execution when working with blacktop.
Special Circumstances
There are instances where it may be possible to lay new asphalt over deteriorated pavement, but the results can vary greatly. For example, if the existing pavement has cracks or is set improperly, the first step should be to address the drainage and base conditions. This involves ensuring the underlying gravel base is sufficient to prevent frost heaving and uneven settling. Additionally, any old pavement that is not in good condition may lead to premature deterioration of the new asphalt layer.
If the existing driveway has been damaged due to poor drainage or an insufficient gravel base, deeper excavation may be necessary. This ensures that both drainage and the base are corrected, creating a solid foundation for the new asphalt layer.
Considerations for DIY or Professional Installation
If you decide to replace a driveway with blacktop, you may choose to do it yourself or engage a professional contractor. Renting the necessary equipment can help in DIY projects, but some rental yards only rent to tradesmen. Engaging a contractor can ensure that the job is done correctly and meet the necessary standards.
Porous paving is another method that can be considered for replacing a driveway. While porous paving allows for maximum attention to detail in terms of drainage and base preparation, the same issues of proper gravel base and adherence to local codes still apply. This method also allows for flexibility in terms of timing and pace, which may be beneficial for DIY enthusiasts.
Conclusion
In conclusion, while it is possible to lay new blacktop over an existing driveway, careful planning and preparation are essential. The condition of the existing surface, the quality of the base, and the potential risks must all be considered. Whether you choose to do it yourself or hire a professional, taking the proper preparation steps is critical to a successful outcome.