Precast concrete wheelchair ramps are commonly used because they are quicker to install than cast-in-place concrete ramps. While precast concrete can be a good choice for certain applications, it has drawbacks that could be avoided by using aluminum. A few of the drawbacks of precast concrete ramps are as follows:
- Site measurements must EXACT. Precast concrete wheelchair ramps are poured into the mold off-site and then transported to the construction site, so the site measurements need to be exact. Taking perfect measurements doesn’t sound difficult, but construction sites often experience obstacles and door threshold heights can change unexpectedly. That means that if the measurements for the ramp were taken before the door threshold height changed, the measurements will be wrong, and the ramp will no longer fit the application.
- Installation requires rental equipment. Precast concrete wheelchair ramps have a shorter installation time than cast-in-place ramps, but precast concrete structures weigh about 150 lbs. per cubic foot which means that special equipment is required to move the sections.
- Concrete is prone to cracks. Concrete’s tensile strength is relatively low compared to other materials which means that it is susceptible to cracks. Common types of cracks are settlement cracks and shrinkage cracks. Settlement cracks occur when the building and the wheelchair ramp drop below their original placement height. Shrinkage cracks develop when the concrete is restrained as it dries and shrinks. If the precast for the ramp constrains it while it’s drying, then it is more likely to crack.
The best alternative material to precast concrete is aluminum. Why?
- Installation flexibility. Aluminum wheelchair ramps are built offsite which means that height measurements are needed to begin production. However, there is a range of installation flexibility with aluminum; the aluminum platform legs typically have about 4 inches of adjustability in case the threshold height ends up being a little different than the original measurements.
- No special equipment for installation. Because aluminum is lightweight, a wheelchair ramp can usually be installed by hand within a day; no heavy installation equipment is required to install the product.
- High corrosion resistance. Aluminum has a high tensile strength which means that it won’t crack. It also will never rust or warp. Concrete, along with every other ramp material, experiences at least one of these types of corrosion.
While aluminum may be a little more expensive initially, it will remain intact for longer.
As you can see in the photo above, there is a set of precast concrete steps next to an aluminum wheelchair ramp. The steps have cracks and rust from the handrails while the aluminum is still in good condition. It might be worth it to consider aluminum for more permanent ramp applications.