To start with, they use different substrates. PPGI uses galvanized sheets as being the base metal. They have a zinc coating throughout to prevent moisture, rust, and corrosion from destroying the steels surface.The substrate for prepainted galvalume steel is a combination of 1.6% silicon, 43.3% zinc, and 55% aluminum. The substrate influences their applications which further differentiates the 2 kinds of steel.

The service life of these two types of steel also varies because of the substrates. The substrates prolong the steels service life by protecting them from rust and corrosion. Zinc is the perfect substrate for safeguarding steel from rust. PPGI has near to 99% zinc within its substrate, but PPGL only has 43.3%. This gives PPGI a longer service life in comparison with PPGL. Although aluminum and silicone are great alloys, they arent the best at protecting steel from corrosion or rust. They eventually wear out with time, thus exposing the steel to moisture that leads to corrosion.

There is also a difference between the weight of PPGI and PPGL. Aluminum, zinc, and silicone substrates are heavier than zinc substrates. As a result PPGL is heavier than PPGI. However, many industries prefer PPGI due to its ability to withstand rust and corrosion. The strength of the steel is more or less similar to PPGL. A PPGL sheet covers around 3% extra space compared to a PPGI sheet.