Shares of

Eagle Materials

(EXP) - Get Report

surged more than 13% Wednesday, following large insider buying in the company the day before.

Laurence Hirsch, the company's chairman, purchased 400,000 shares of Eagle for a total $14.1 million over the past few days, according to a filing with the

Securities and Exchange Commission

.

The news sent Eagle Materials' stock up 13.1% to $38.64 in morning trading Wednesday.

The construction materials supplier has seen its shares slip in recent months as investors fear a slowdown in the residential construction market. About 50% of the company's revenue comes from the sale of gypsum wallboard (much of the rest comes from cement).

As the market for new-home construction slows, Eagle is

counting on the commercial construction market and the home-remodeling boom to pick up the slack in wallboard demand.

Hirsch has served as the company's chairman since July 1999. He previously served as a director and chief executive of

Centex

(CTX)

, the homebuilder that spun off Eagle in 2004.