Cows emit a massive amount of methane through belching, with a lesser amount through flatulence. Statistics vary regarding how much methane the average dairy cow expels. Some experts say 100 liters to 200 liters a day (or about 26 gallons to about 53 gallons), while others say it's up to 500 liters (about 132 gallons) a day.
1 According to author Stu Silverman the average cost of adding a garage begins at roughly $7,500, and for a two-car garage the average costs will go much higher.2  This sort of structure will average at $27,040. 3  The resale value of this update would hold at $21,635, or a nearly 81% return on investment.or the garage addition, the typical costs include: 1  According to author Stu Silverman the average cost of adding a garage begins at roughly $7,500, and for a two-car garage the average costs will go much higher. 2  The above figures place the garage addition at $40 per square foo t.
The cost of new construction depends on the quality of materials, the size of the building and the wages of designers and laborers. An average garage can be built for around $40 to $60 per square foot, with an apartment adding anywhere from 20 to 40 percent to that cost. A 20-by-20-foot garage totalling 400 square feet would cost between $16,000 and $24,000 without an apartment, and anywhere from $20,000 to $35,000 with an apartment. Homeowners who are skilled at construction and can do some or all of the work themselves can cut an enormous amount off of those numbers.