Boolean operators are specific words used to combine keywords to improve the chances of finding relevant information. The most commonly used Boolean operators are AND, OR and NOT. Search results will contain both of the terms humour and therapy. Using AND decreases the number of results, because each time a keyword is added, the focus of the search is narrowed. Search results will contain one, or both, of the terms humour or laughter or comedy. Using OR increases the number of results, because a broader range of keywords is searched.
The actual cost of a flat roof depends on your location, the materials used, the complexity of the installation, and other factors. 1  Building a flat roof costs approximately $1.50 to $10.00 per square foot. 2  Assuming an average roof size of 1,500 square feet, that s a total cost of $2,250 to $15,000.
Tile Roof Average Costs. Ceramic roof tile costs starts at approximately $5 to $15 per square foot but could cost as much as $15 to $30 per square foot or more. For a 2,000 square foot roof, this amounts to a total cost of around $10,000 to $60,000. Concrete roof tile costs are generally around $5 to $10 per square foot, or $10,000 to $20,000 for a 2,000 square foot roof. Tile is a heavy material, and it is sometimes necessary to upgrade a home's structural support to accommodate the added weight of a tile roof.