Aluminum ladders offer high strength and lightweight portability, but there are several drawbacks that you will want to consider. Aluminum conducts electricity very well, which could be a problem if you intend to work near power lines or other electrical wiring. Chemicals and salt water environments tend to weaken these types of ladders.
Fiberglass ladders do not act as a conduit for electricity and are essentially corrosion-proof. These rugged ladders require little maintenance and can last for many years. If a fiberglass ladder is cracked, its durability will be compromised.
Fiberglass and aluminum ladders are comparable in several areas, including weight capacity and pricing. Most models of these types of ladders are capable of supporting between 250 and 375 lbs. and range in price from $199.99 to $467.99, as of 2011. Exact specifications and pricing will vary from manufacturer to manufacturer.