By David Russell, reporter at OptionMonsterNEW YORK -- The bulls piled into homebuilders and related stocks on Friday, triggering a flurry of upside option activity. Mohawk Industries ( MHK), a maker of flooring products, hit shortly after the open as investors snapped up the November 115 calls, most of which priced for $9.85. More than 2,400 of the options traded against previous open interest of just 195 contracts, indicating that new positions were initiated. Mohawk rose 3.58% to $121.38. These calls lock in the price where shares can be purchased, letting investors cheaply position for upside and control the amount of money that can be lost to the downside. They can also generate significant leverage when a stock goes up. Less than an hour later, lumber company Weyerhaeuser's ( WY) October 30 calls traded more than 5,000 contracts, most of which priced for 25 cents. Upside activity followed in cement giant Cemex ( CX), with almost 7,000 October 11 calls going for 63 cents to 68 cents. Weyerhaeuser rose 2.7% to $28.51, and Cemex advanced 2.16% to $11.33. Investors targeted home-improvement company Lowe's ( LOW) in another transaction. OptionMonster's scanners showed the purchase of 5,100 September Weekly 46 calls expiring this Friday for 47 cents and the sale of an equal number of Weekly 47 calls for 12 cents. The strategy will control a move between the two strike prices for just 35 cents, implying profit of almost 200% on a close above $47 five days from now. Lowe's fell 0.57% to $45.60. Finally, after nibbling around the edges of actual homebuilders, traders targeted KB Home about halfway through the morning. This time they wanted a little more time and amassed more than 5,500 January 16 calls, with the biggest block fetching $2.26. KB Home ended the session up 2.14% to $16.24. Russell has no positions in any of the companies mentioned in this article.