Issue link: https://read.dmtmag.com/i/112125
SERVICE & SET-UP Dry Subject (But Cool) BY GEORGE PORTER Recently I had the good fortune to be invited by a fine fellow named Tony Widowski for a seminar on Frost Free Foundations in Wisconsin. It was part of a greater training secession by the Wisc. Housing Alliance on foundations in general. We discussed slab, insulated, and frost free methods of supporting a home and there were in excess of 90 people in attendance. This would be in spite of the large winter storm that seems to occur every time I get near that state. Oh Well! If cold air produces such warm people then I guess it is just fine��� but a wind chill of ���31 is pushing it a bit! With this as a background, you can only imagine what the frost line is there; roughly 4 feet. This means that to make a conventional foundation you would have to dig into the earth 40 to 48 inches or more depending on where you were in the state. Also times the number of footings you wanted under the home. This is lots of trouble and treasure so if anyone should be interested in a way to save on all this digging it would be them. We are headed into our third year since the blessing of an engineer���s stamp on the frost free foundation so I thought because of its much smaller cost it would be the foundation of choice. Not so. It is without surprise that while installers might like to use it, many ���officials��� both local and state all around the nation don���t trust it, understand it or maybe even believe it. We are setting a home right on top of the ground just like we did in the 40���s through the 80���s! That just can���t be right and the officials are just not going to buy this cheap trick. At the risk of replacing opinion with fact let me try to explain again how this works. In most of man���s scientific evolution we have an invention and then we tweak and perfect over time. Sometimes after generations we keep adding to the layers of improvement and we turn the invention of the wheel into NASCAR. The Wright Bros. project evolves into space shuttles. We add to what we know and it gets even better. People have always dug down below the frost like to keep foundations safe from the freezing and lifting efMARCH 2013 14 THE JOURNAL fects of frost. An unstable foundation i.e. one that doesn���t stay in a stationary position will flex and twist a structure located on it and bad things will happen to the functioning of that structure. Walls crack, doors stick, floors creak and so forth so you had to dig. 40 years ago a fellow discovered that if you insulate the area around the foundation, the temperature of the earth would warm the area under the insulation and the water in the ground would not freeze and therefore there was no ice to do any lifting. This is actually raising the frost line to the level above the insulation and the part left in the foundation above this point is now below that level. So it works; provided you have fairly normal soils and adequate insulation for the area the home is located in. The farther north you go the colder it gets and the more insulation you need to do the job. There are still people who don���t understand this but after 40 years most do get it by now. One of the biggest problems with the Frost Free Foundation is, in my opinion, is that it does not build on something we already know exactly. To understand this concept we do not add a layer to an existing set of facts we have to go back to the very basic beginning. Frost heave always has and always will require these three things to happen. 1. Soil with the ability to retain some moisture. 2. Water that has more than 80% saturation in that soil. 3. Freezing temperature in that soil below the depth of the footing. This is the three-legged stool of frost heave. Take one away and it will not happen. The first two foundation methods listed previously; dig below or insulate, remove the third leg. If the ground does not freeze under the footings then it cannot lift them. This is a 99% truth. There is such a thing as tangential frost heave where it grips the sides of the footing but that is a different topic and solution. So far in the history of construction we have only dealt with the temperature aspect. Let���s look at the water mentioned in #2. Forget all you know about frost line and ask yourself this question, ���Can you make ice without water?��� I would hope we all came up with the same answer here. No. But what about a little bit of water? How much is too much? Well��� around 80% saturation is too much. Why 80%? There is a very involved scientific explanation and if you have an hour or two sometime I can explain it all to you. But it also has a short version that works pretty well. Water molecules have an electric charge like a magnet and that is what keeps them together like all other molecules. Waters molecules do not have a very strong charge and are easily broken down. The natural state of water is ice. Add some heat to bring it above 32 degrees F and they break down from ice (solid) to liquid. Add still more heat and they break down even further. At around 212 degrees F the liquid will turn to a gas. Now let���s think about putting all this back together. If we can catch all the steam made and cool it we might end up with our water again but it is now spread out and it will be very hard to get that done, probably impossible. Now let���s think about the liquid we made from ice. Remember it recombines the molecule by attracting other molecules and there is a limit to the reach of that electrical pull. If there are no other molecules near it then there are none to attract and it does not combine to make the ice. That ���nearness��� is defined by the saturation and when it is less than about 80% it can���t combine enough to make a lifting ice lens. (Told you this was cool!) To be continued next month. T J George Porter is a consultant to the manufactured housing industry. His Company is Manufactured Housing Resources, P.O. Box 9, Nassau, DE 19969, (302) 645 5552, Web: www.george-porter.com. Some of his services are both in person and On-line training for certification in many states plus expert witness and investigation for the industry.