Exhibit 99.1


     ElkCorp Increases Earnings per Diluted Share Outlook to $0.72 to $0.74
    for its Fiscal Third Quarter; Company to Present at SunTrust Conference
                           April 12 at 8:10 a.m. EDT

     DALLAS--(BUSINESS WIRE)--April 11, 2005--ElkCorp,  (NYSE:ELK), announced an
increased earnings outlook for its third fiscal quarter of 2005, ended March 31,
2005.  The company now expects  earnings per diluted share to be in the range of
$0.72 to $0.74  compared to the $0.62 to $0.67 per diluted share  guidance given
in ElkCorp's second quarter earnings release dated January 20, 2005.
     The  increased  estimate  for the  quarter  is  primarily  driven by record
laminated shingle shipments, production improvements and improved pricing, which
offset  continued high raw material and  transportation  costs.  The better than
anticipated  performance in the company's  roofing business was partially offset
by a challenging quarter in the composite lumber business.  Slower than expected
ramp up of new production, higher than anticipated raw material costs and slower
than anticipated  ramp-up of Elk's new line of products for non-decking  markets
resulted in lower than anticipated  results.  Because of the challenges faced in
the third  quarter the company  does not expect the  composite  business to meet
prior expectations for the fiscal year.  However,  the company remains confident
in the platform's ability to meet its long-term goals. The recent appointment of
a new  Executive  Vice  President  as well as the  addition of key  personnel to
provide  enhancements  to the  composite  platform's  organizational  structure,
combined  with the  capacity  added as the  newly  commissioned  extruders  come
on-line,  will  assist  Elk  in  taking  advantage  of  the  substantial  growth
opportunities in these key markets.
     "We  continue to see strong  demand from the areas  affected by  hurricanes
last year and we  anticipate  this demand to continue  throughout  the  calendar
year,  although we do expect  demand to trail off toward the end of the calendar
year," said Thomas Karol,  chairman and chief executive officer of ElkCorp. "The
significant  shingle demand has brought our inventories lower than we would like
but we have been able to leverage  efficiencies  in  production  to increase our
shingle shipments to record levels and service demand.  Raw material and freight
costs  remain  high  throughout  the  industry;  however,  we have  been able to
effectively  manage expenses and minimize the overall impact of these costs with
offsetting price increases."
     Mr. Karol continued,  "In our composites business,  we faced some obstacles
in the  quarter  such as  longer  than  anticipated  code body  approval  of our
products, higher raw material costs and a slower than anticipated ramp-up of our
composites into non-decking  markets. We continue to make progress in addressing
the  issues  faced in this  quarter  and are  pleased  with the  impact  the new
organizational  structure has made since their appointment.  We are confident in
the future of this product  platform and its  long-term  positive  impact on the
business."
     The company  will  release its fiscal  third  quarter  results on Thursday,
April 21, following the close of the market. ElkCorp will also host a conference
call on April 22, 2005,  at 11:00 a.m.  EDT to further  discuss its earnings and
operations for the third quarter as well as expectations  for its fourth quarter
and fiscal year end.  Investors and other interested  parties may participate in
the live audio webcast by visiting the investor relations section of the ElkCorp
Web site at www.elkcorp.com.
     ElkCorp will be  presenting at the SunTrust  Robinson  Humphrey 34th Annual
Institutional  Investor Conference on April 12 at the Ritz-Carlton,  Buckhead in
Atlanta.  Chairman and Chief  Executive  Officer Thomas Karol will be addressing
key investors and analysts regarding the Company's operations and strategies for
the  future.  A live  audio Web  broadcast  of the  presentation  will  begin at
approximately  8:10 am EDT and can be accessed  through the  investor  relations
section of the  ElkCorp  Web site.  A replay of this  presentation  will also be
available on the site for 30 days.

    About ElkCorp

     ElkCorp,  through its subsidiaries,  manufactures Elk brand premium roofing
and  building   products  (over  90%  of  consolidated   revenue)  and  provides
technologically  advanced  products  and services to other  industries.  Each of
ElkCorp's  principal  operating  subsidiaries  is a leader within its particular
market.  Its common stock is listed on the New York Stock  Exchange  (NYSE:ELK).
See www.elkcorp.com for more information.

    Safe Harbor Provisions

     In  accordance  with the  safe  harbor  provisions  of the  securities  law
regarding forward-looking  statements, in addition to the historical information
contained herein, the above discussion contains forward-looking  statements that
involve risks and  uncertainties.  The statements that are not historical  facts
are  forward-looking  statements  within the meaning of the  Private  Securities
Litigation Reform Act of 1995. These statements usually are accompanied by words
such as "optimistic,"  "vision," "outlook," "believe," "estimate,"  "potential,"
"forecast,"  "project,"  "expect,"  "anticipate,"  "plan,"  "predict,"  "could,"
"should,"  "may,"  "likely,"  or similar  words that convey the  uncertainty  of
future  events or outcomes and include the earnings  outlook for the fiscal 2005
third quarter.  These statements are based on judgments the company believes are
reasonable; however, ElkCorp's actual results could differ materially from those
discussed here. Factors that could cause or contribute to such differences could
include, but are not limited to, changes in demand,  prices, raw material costs,
transportation  costs, changes in economic conditions of the various markets the
company serves, changes in the amount and severity of inclement weather, acts of
God, war or terrorism,  as well as the other risks detailed  herein,  and in the
company's reports filed with the Securities and Exchange  Commission,  including
but not  limited  to, its Form 10-K for the fiscal year ending June 30, 2004 and
Form 10-Q for the  quarter  ended  December  31,  2004.  ElkCorp  undertakes  no
obligation to update or revise publicly any forward-looking statements,  whether
as a result of new information, future events or otherwise.

    CONTACT: ElkCorp, Dallas
             Investor Relations Contact
             Stephanie Elwood, 972-851-0472