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.
Put it off and you could end up with a leaky roof-or worse, a collapsed roof. The cost of roof replacement depends on the materials you choose, the size and pitch of your roof, your geographic location and more. Very generally, the average job with mid-grade materials will cost about $5,000 to $10,000. Regular asphalt shingles: $140 to $320 per square, depending on type, quality and local labor rates. 2  The average roof requires 20 to 30 squares, which brings the total cost to $2,800 to $9,600.