Silane & Siloxane Concrete Sealants
It is possible to minimize stains on concrete if you make the surface smooth using a steel trowel, but trust me, this is very slippery! I do NOT recommend steel trowel finishes for concrete that has the possibility of getting wet on a regular basis.
The better method is to simply apply a clear sealer or liquid repellent. There are many types available but I feel that those containing silanes and siloxanes are among the best. These chemicals partially fill the pores of the concrete matrix and simply don't let the water and oil molecules pass through and into the concrete. The liquids stay on top of the surface.
Many of these products are available at specialty concrete supply stores. Most major cities and towns have these. Open your Yellow Pages and look under Concrete Supplies. Beware of heavily advertised consumer products. These often contain silicones or other similar chemicals. Avoid these if possible because some of these products are film formers and simply lay on the surface of the concrete. Some of them don't allow the concrete to breath. This is a bad thing especially if you live where the temperature drops below 32F. Water vapor from the soil passes through concrete and the film formers can block this movement resulting in damage to the concrete surface.
The following products are great for minimizing oil stains on concrete:
- Aquapel / L & M Construction Chemicals
- Masonry Saver / SaverSystems
Aquapel and Masonry Saver are sold through distributors and paint stores. Protecrete can be purchased direct from the manufacturer and from various stores. Check on the web sites of all these companies to see if there is a store near you, before you make a mistake and purchase an inferior product.