UPDATE 1-Standard Pacific posts much steeper quarterly loss

(Adds estimates, charges, orders, revenue)

NEW YORK, May 12 (Reuters) - Home builder Standard Pacific Corp (SPF.N) on Monday reported a much steeper quarterly loss due to the continuing market slowdown and the use of incentives to move inventory.

The company, which builds homes chiefly in the western United States, also said it faced a Wednesday deadline for a deal with lenders to extend a waiver of default on its debt.

Standard Pacific said its first-quarter net loss widened to $216.4 million, or $3.34 per share, from $40.8 million, or 63 cents per share, a year earlier.

The results included impairment charges of $1.82 per share for inventory and other items as well as a separate tax-related charge of $1.29 per share.

The average forecast of analysts polled by Reuters Estimates was for a loss of $1.52 per share, but it was not immediately clear which items that figure included.

The U.S. housing market has been in a steep downturn for more than a year, with rising mortgage defaults and falling home prices. As a result, builders have shifted their focus to survival, turning the excess land and inventory accumulated during the boom times of 2002 to 2006 into cash.

Standard Pacific's revenue fell to $348.2 million from $651.1 million and missed the analysts' average forecast of $384 million.

The Irvine, California-based company ended the first quarter with $328.8 million in home building cash.

Standard Pacific also said it was again seeking to extend a waiver of default on its debt. If the waiver is extended from May 14 to Aug. 14, as the company requests, it will agree to reduce its revolving credit facility to $500 million from $700 million.

An earlier extension agreed to in March had reduced the credit facility commitment from $900 million.

The company expects to complete the waiver extension on time, but said there was no assurance that this would happen.

Net new orders for the quarter fell 30 percent to 1,245 homes. Prospective buyers canceled their orders at a rate of 24 percent, the same as in the year-earlier quarter, but down from 37 percent in the fourth quarter. (Reporting by Nick Zieminski, Patrick Fitzgibbons and Ilaina Jonas; Editing by Lisa Von Ahn)