The code requires that you put draintile around the entire perimeter of the house at the bottom of the footing and then daylight it and /or run it to a sump tank. Installing the drain tile on the inside of the footing is known as cosmetic.
The code also requires that 1/2 of the depth of the excavation around the building is back filled with course fill rock, sand and/or gravel.
This helps drain groundwater down to the draintile. If the excavation was 8′ deep, then you must back fill 4′ with course fill.
If you are building heavy clay, the building site may have pockets of water or even underground rivers. To help keeping your foundation wall protected install Blackdog waterproofing.
Using Blackdog waterproofing is 1 way to insulate the foundation and drain the whole depth of the hole to remove all the groundwater.
The reason why water expands upon freezing is because of the strong hydrogen bonding between the water molecules. Water is polar having a positive end nearest the Hydrogens and a negative end nearest the Oxygen atom. Therefore the positive ends of some water molecules attract the negative ends of other water molecules.
When groundwater is next to the surface it will push hydrostatic pressure and/or heave frozen dirt against the foundation wall.
When you have high level of ground water and/or let’s say you build a house in clay, then back fill area is more porous fill because you are in clay the ground water goes where it can travel easily in porous soil, now the porous soil is full of groundwater and winter sets in the frost goes down for 10″ in the central part of the country to 6′ or more in the northern parts of the country.
When the ground water freezes ground it’s the volume of water expanses10% larger than when it was in the liquid form. Creating an incredible force on any foundation whether it’s a full basement or just frost footings.
Making a place for water to drain is a prudent and proper thing to do; it will save your house now and in the winters to come as well as reducing the risk of mold problems.