Ladders made from wood are frequently not as sturdy as those made from other materials, however, and wood can deteriorate over time to compound the strength problem. The main advantages of aluminum ladders are their light weight and strength. Since aluminum readily conducts electricity, they should not be used for electrical work or near wiring. Fiberglass is considered the premium ladder material because it won't conduct electricity, and is strong and relatively light in weight. A rating system helps buyers gauge the strength of different stepladders.
Prices are highest for the strongest ladders.
Type IA ladders, which have a load capacity of 300 pounds, are the strongest and are geared to heavy-duty use by contractors. Most ladders will actually support somewhat more weight than the rating indicates, but I recommend a Type II or stronger ladder for homeowners, unless price is the main consideration. Before buying any stepladder, it pays to open it and check it for stability. Ladders that sway when climbed should be avoided. A pail shelf, which generally opens at the back of the ladder behind the top step, is another good feature, especially if the shelf closes automatically when the ladder is folded.