Posted by Fritz Fromherz on March 31, 2015

Retrofitting Boardwalks On Top of Existing Foundations with PermaTrak

See other great resources on: Boardwalk Materials, Boardwalk Construction

Retrofitting Piers, Pedestrian Bridges, Boardwalks, and more

Many popular trails and boardwalks have been built in beautiful settings that draw visitors regularly.


Those sites include timber or composite structures that are outdoors and in harsh environments. The trails and boardwalks eventually become worn and may exceed safe structural design guidelines and become functionally obsolete. There are trails that have deteriorated decks, substructures and foundations (the photo on the right is an extreme example of this). Designers and their clients are often faced with the need to replace portions of trails and boardwalks. In some cases, even the complete structure must be replaced.

Many times, we are unable to install our concrete boardwalk system on top of existing foundations because support beams and foundations are not designed to handle the loads of a concrete deck. For example, Southern Yellow Pine has a density of about 52 pounds per foot with decking made from 2x4s which are approximately 1.5" thick. Our decking pieces have a density of 150 pounds per cubic foot, and are either 4" or 5.5" thick (depending on load requirements and structure width), which means that the weight of a concrete deck is 8-11 times heavier than that of a typical timber deck. Timber support beams are typically not designed to handle the loads of a concrete deck. However, there are times that we can install our boardwalk system on an existing foundation. A few examples of this type of application are below.  

PermaTrak Retrofit Projects - Timber Foundations

Structures built with substantial foundations can be an excellent PermaTrak retrofit opportunity.


Concrete pilings or caissons have been used on some structures, particularly near or over water. There are many sites that have deteriorating decks and substructures, but the treated wooden pilings below can be found to be quite suitable for many years of use. PermaTrak can be used on foundations like these very successfully. A good policy would be to survey the potential foundation system that is in place. If a survey proves the foundations are worthy of pairing with a new deck system, then PermaTrak can be an excellent long term addition rather than using timber again. PermaTrak has the design capability and experience to be counted on to provide a solid joining of strong, existing foundations with the attractive, durable PermaTrak components.

PermaTrak Retrofit with City of Sarasota, FL - Piers at Van Wezel

In the past, we have been able to reuse existing piles and replace the beams and decking with PermaTrak. This option involves extensive investigating and engineering. Existing piles would need to be load tested by a structural engineer to ensure that they are capable of handling expected loads, and the site would need to be surveyed to determine the exact locations of existing piles. 

PermaTrak recently provided the City of Sarasota with the design and material that allowed the City to utilize existing concrete piling and durable PermaTrak precast beams and treads to give the City (4) brand new observation decks right on the shoreline of Sarasota Bay adjacent to the Van Wezel Performing Arts Center. The previously installed weathered timber decks are gone and the new concrete PermaTrak decks enhance the spectacular views of the bay.Van_Wezel_Sarasota_Piers_before_after

PermaTrak Retrofit Projects - Train Trestles

There are transportation structures all over the US that are particularly well suited to be retrofitted with the PermaTrak precast boardwalk system.

boardwalk foundation trestle

Those structures are the many obsolete train trestles that are found at sites, both urban and rural. These bridge trestles tend to be heavily built, they have many years of design life remaining when used for multi-purpose trails and elevated observation decks. PermaTrak precast components are perfectly suited to be used with these sturdy structures. Once the old railroad track and ties are removed, the hearty bridge structure allows the longitudinal precast beams to work in harmony with attractive PermaTrak boardwalk treads. These are practically natural retrofit projects that will be in place for decades.   


Yes, PermaTrak boardwalk systems can be a terrific answer for use in retrofit applications. PermaTrak can extend the life of previously well designed foundation systems or of proud, older transportation structures. Retrofitting structures is a sound plan for communities when replacing trails or boardwalks with foundations that have enough capacity to handle PermaTrak.

2nd photo by Charles Haynes, 4th photo by Len Matthews

Note: visit our Florida boardwalk photo gallery for more photos of the Van Wezel Piers by PermaTrak


More construction photos: 

  • Van Wezel - Sarasota, FL - PermaTrak South Pier
  • van wezel timber pier
  • sarasota boardwalk retrofit
  • sarasota van wezel pier foundations
  • permatrak caissons sarasota
  • permatrak caps caissons sarasota florida
  • permatrak pier sarasota
  • permatrak pier van wezel sarasota
  • sarasota permatrak pier

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About This Blog

The PermaTrak boardwalk blog articles are written for landscape architects, engineers, and agency or municipality professionals.

We aim to provide educational resources for designing and building boardwalks, pedestrian bridges, trail and greenway systems. 

By reading our weekly posts, you will deepen your understanding of boardwalk design, cost estimates, and construction practices.