QuickLinks -- Click here to rapidly navigate through this document

Exhibit 12.1

Atkore International, Inc.

Computation of ratio of earnings to fixed charges

Our ratio of earnings to fixed charges for each of the periods indicated (dollars in millions):

		Period from Dec. 23, 2010 through March 25, 2011			Period from Sept 25, 2011 through December 22, 2010			2010			2009			2008			2007			2006
Earnings:
Income (loss) from continuing operations before income taxes			(9	)		(3	)		20			(1,004	)		289			118			265
Amortization of capitalized interest expense			—			—			—			—			—			—			—
Capitalized interest			—			—			(1	)		(1	)		—			—			—
Fixed charges, as below			14			12			52			46			30			16			31
Total earnings, as defined			5			9			71			(959	)		319			134			296
Fixed charges:
Interest expense, net of capitalized portion			13			11			48			41			26			12			27
Capitalized interest			—			—			1			1			—			—			—
Rental expense, representative of interest			1			1			3			4			4			4			4
Total fixed charges, as defined			14			12			52			46			30			16			31
Ratio of earnings to fixed charges			0.4			0.8			1.4			(20.8	)		10.6			8.4			9.5
ESTIMATE OF INTEREST WITHIN RENTAL EXPENSE
Total rent expense			3			3			10			12			12			12			11
Estimated percentage (based on SEC guidance)(a)			33	%		33	%		33	%		33	%		33	%		33	%		33	%
Estimated interest within rental expense			1			1			3			4			4			4			4
Earnings were inadequate to cover total fixed charges by			(9	)		(3	)					(1,005	)

(a)

One third of rent expense is deemed to be representative of interest.

        For purposes of calculating such ratios, 'earnings' consist of operating income (loss) before income taxes plus fixed charges and amortization of capitalized interest less capitalized interest. Fixed charges consist of interest expense, amortization of debt issuance costs, capitalized interest, and an estimation of the portion of rent expense representative of the interest component within rent expense.

QuickLinks

Exhibit 12.1