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.
The cost of replacing a roof is based on two factors, the price of the materials and the price of the labor involved. Materials vary dramatically in price and can cost between $0.72 per square foot, all the way to $20 per square foot.The cost for a roof replacement can vary dramatically from one material to the next. We've put together a list of materials along with some sample costs. Asphalt Shingles - $2.75 - $5.75 psf installed.ur cost calculator to the right begins with the question of removal or tear off and estimates this cost at $2 per square foot (if you answer no it does not affect the project pricing). We then ask for your desired roof material-select from the following;