There’s no denying that because boardwalks made of wood have been around for such a long time, they have become the default material that boardwalk designers and specifiers automatically think of when designing boardwalks. But is wood really the best material that could be used these days with more modern alternatives now commonly available which have excellent characteristics for demanding outdoor environments.
So let’s look at how wood stacks up against four of the primary alternative materials – fiberglass grating, steel grating, composite wood and pre-cast concrete.
PRESSURE TREATED SOFTWOOD
| Advantages | Disadvantages |
| Most familiar material with contractors | Prone to decay and/or insect attack |
| Typically readily available near to job sites | Can crack, warp and twist |
| Can be easily cut to precise size on site | Slippery when wet |
| Easy to carry on site without heavy equipment | Higher ongoing maintenance costs |
| Relatively low cost | Algae and moss growth increase slippage |
| ‘Natural’ appearance | Concerns about leaching of preservative chemicals |
| Readily recyclable | Low fire resistance |
| Moderate lifetime only – 10-15 years |
FIBERGLASS (FRP) GRATING
| Advantages | Disadvantages |
| Exceptionally slip resistant in wet, dry or icy conditions | May be more expensive than wood |
| Open mesh allows sunlight and water to reach vegetation below | More ‘natural’ look of wood may be preferred |
| Excellent in marine environments – unaffected by salt spray | Non-biodegradable |
| Lighter than steel or concrete – relatively easy to carry onto site | Unfamiliarity with specifiers and contractors |
| Large size panels can speed installation | |
| Can be cut to size on site | |
| Rated Class A for fire resistance | |
| Can be supplied in colors to match surrounding environment | |
| Can construct inclined access ramps with no slip danger | |
| Excellent for steps and stairs. |
COMPOSITE WOOD
| Advantages | Disadvantages |
| Can be carried on site without heavy equipment | Low structural strength – requires additional joists to support |
| Typically readily available near to job sites | Slippery in cool, wet climates |
| Can be easily cut to precise size on site | Can be extremely flammable |
| Available in a range of colors | Relatively soft – susceptible to scratches |
| Generally non-renewable and non-biodegradable | Susceptible to mold, moss & mildew |
| Historical issues with fading & warping |
STEEL GRATING
| Advantages | Disadvantages |
| Grid allows sunlight to reach vegetation below | Subject to corrosion and degeneration over time, especially in marine environments |
| Galvanized steel has a design life expectancy of 50+ years in non-marine environments. 20-25 years in coastal environments | Typically requires heavy equipment for installation |
| Non-combustible | Can’t be cut to size on site- pre-fab needed |
| Very good slip resistance | Relatively expensive |
| High impact strength | |
| Construct inclined access ramps with no slip danger | |
| Excellent for steps & stairs |
PRECAST CONCRETE
| Advantages | Disadvantages |
| High slip resistance | Cannot be hand carried on site |
| Very good durability – 50+ years | Requires pre-defined boardwalk alignment |
| Non-combustible | More expensive than most alternatives |
| High impact strength | More difficult to transport |
All things considered, it’s hard to deny the significant benefits of fiberglass grating for boardwalk construction – especially its exceptional slip resistance, the broad, level surface of the panels, its fire resistance and its durability, particularly in coastal environments. And in remote areas where access is difficult for major maintenance due to deterioration or decay of conventional wood boardwalks, FRP grating shows clear advantages.
On the other hand, FRP really has very few disadvantages as a material for boardwalks or surfaces for small bridges on bike tracks and trails, wetland walks and suchlike. While some people may not immediately take to the perhaps more industrial look of fiberglass panels, there is the offsetting advantage that fiberglass panels can be supplied in colors that will blend in extremely well with the surrounding environment, reducing the impact of raised boardwalks. And yes, it does mean that the boardwalk structure would need to be constructed of two materials, typically a steel sub-structure and posts and railings where required. But again, if steel is used, it can be painted in a color to match the FRP and the immediate environment.
FRP grating would undoubtedly be one of the best materials used for constructing steps and stairs, rivalling steel grating in this respect. It also offers the advantage that the same material can be used on any platforms or viewing platforms which are accessed by the stairs, giving a more aesthetically coordinated look. And the nosing on the stairs can be constructed with a strip of gritted fiberglass supplied in a contrasting color of material, about 2” wide offering both greater visibility and extra slip resistance, thus adding an extra level of safety for pedestrians.
For stairs or beach access ramps however, the gritted surface which normally provides such excellent slip resistance, can prove somewhat hard on the feet for beach users. In such locations there is the alternative of supplying FRP grating with a meniscus finish which gives good slip resistance but is not so hard on the bare feet.
In summary, although wood has served for an exceptionally long time as the default material for boardwalks, it’s surely time to look at other materials, and in this respect, FRP grating exhibits an impressive array of advantages that puts it head and shoulders above competitive materials.