Use a heavy vinyl floor in a wall tent If you are going to use a floor. Fold the sod cloth to the inside then place the floor on top of the sod cloth. In this manner, any water is forced under the floor. Also, bugs are forced under the floor reducing the number of insects entering your tent.
We have heavy 18 oz vinyl floors that are very durable. If you use a cheap thin Walmart tarp it is likely there will be punctures in the cheap floor if there are small twigs or small rocks under the floor.
Always use a floor that does not have a cut out or zippered area because water and bugs can come in through openings in the floor.
Having a floor is recommended as it makes camping much more enjoyable. No dirt or water in the tent with reduced bug problems.
I am often asked if it is ok to use canvas as a tent floor. The quick answer is no.
A canvas tent floor will absorb water regardless if it is water and mildew treated. A canvas roof does not absorb water and leak because the roof is at an angle and rain runs down the roofline and side walls quickly. A canvas floor will have pools of water if you are in rain or snow conditions.
Additionally, a canvas floor will turn black and have mold on it. Not healthy.