During the 3rd quarter, our commitment to safety resulted in an RIR of 0.64, which is a significant improvement compared to the same period last year, with more than half of our facilities operating injury-free for more than a year.
Financially, we delivered record 3rd quarter revenue of $2.2 billion, an increase of 16% compared with the same period last year and adjusted EBIT of $400 million.
This resulted in an adjusted EBIT margin for the Company of 18% with all 3 of our businesses, posting double-digit EBIT margins for a 5th consecutive quarter.
I would like to take a few moments now to share more about the work we are doing with 2 of our product lines to position us for the future.
The Dutch product line is primarily used in automotive and electronic applications and generates annual revenues of approximately $270 million.
Given our commitment to sustainability, I'm pleased to note that PINK Next Gen insulation is made with 100% wind powered electricity in such an industry standard for recycled content.
As Brian commented Owens Corning delivered another outstanding quarter with strong revenue and earnings growth across all 3 businesses.
Overall positive price realization more than offset the inflation headwind in all 3 businesses in the quarter and year-to-date.
As a result, 3rd quarter operating margins reached 18% nearly 300 basis points higher than the same period last year.
Wwe reported consolidated net sales of $2.2 billion for the 3rd quarter, that's up 16% over 2020 and produced double-digit revenue growth in all 3 segments.
Adjusted EBIT for the 3rd quarter of 2021 was $400 million, up $111 million compared to the prior year.
Earnings grew year-over-year, in all 3 businesses, resulting in double-digit EBIT margins for the 5th consecutive quarter.
Adjusted earnings for the 3rd quarter were $162 million or $2.52 per diluted share compared to $193 million or $76 per diluted share in the 3rd quarter of 2020.
Depreciation and amortization expense for the quarter was $129 million, up $9 million compared to Q3 2020.
our capital additions for the 3rd quarter were $90 million, up $22 million as compared to the 3rd quarter of last year.
Slide 6 reconciles our 3rd quarter adjusted EBIT of $400 million to our reported EBIT of $394 million during the quarter we recorded $20 million of restructuring costs associated with previously announced actions, which includes $19 million for the Santa Clara facility sale.
Those charges were partially offset by a $15 million gain on the sale of land related to a previously announced facility closure.
In addition, we had $1 million of acquisition related charges for, which was acquired during the quarter.
Q3 adjusted EBIT increased $111 million over the prior year, reaching $400 million.
Despite supply chain challenges and accelerating inflation, all 3 segments delivered year-over-year EBIT growth.
The insulation business, continue to build on the strong performance demonstrated in Q2, delivering double-digit year-over-year EBIT growth and 400 basis points of EBIT margin expansion.
Q3 revenues were $815 million, a 20% increase over the 3rd quarter of 2020.
We continue to execute well in our manufacturing operations and benefited from the recovery of $18 million of fixed cost absorption on higher production.
We delivered margins of 15% and EBIT of $124 million a quarterly record and up from $73 million in the 3rd quarter of 2020.
Sales for the 3rd quarter were $591 million, up 13% compared to the prior year.
Operationally, we continued to execute well with solid manufacturing performance and recovery of $29 million of prior year curtailment costs.
In the 3rd quarter composites delivered record EBIT of $101 million, up $46 million over last year and EBIT margins reached 17%.
The roofing business produced a strong 3rd quarter, sales in the quarter were $869 million, up 14% compared to the prior year.
The US asphalt shingle market was down 9% in Q3 as compared to the prior year, while our US shingle volumes were up slightly year-over-year.
For the quarter, EBIT was $12 million, up 16 million from the prior year, achieving 24% EBIT margins.
Free cash flow for the 3rd quarter of 2021 was $400 million bringing year-to-date free cash flow to $925 million, up $411 million over the same period last year.
With this cash flow performance, we further strengthened our already solid investment grade balance sheet by repaying in the quarter the remaining $184 million due on our 2022 senior notes.
At quarter end, the company had ample liquidity of approximately $2 billion, consisting of $920 million of cash and nearly point $1.1 billion of combined availability on our bank debt facilities.
During the 3rd quarter of 2021, the company repurchased 1.7 million shares of common stock for $160 million.
Through September 30, 2021, the company returned $516 million to shareholders through share repurchases and dividends equating to approximately 56% of year-to-date free cash flow.
We remain focused on consistently generating strong free cash flow returning at least 50% to investors over time and maintaining an investment grade balance sheet.
Now turning to our 2021 outlook for key financial items, general corporate expenses are expected to range between $150 and $155 million.
Capital additions are expected to be approximately $460 million, which is below expected depreciation and amortization of approximately $500 million.
For interest expense, we've narrowed our estimated range to be between $125 and $130 million and finally, we expect our 2021 effective tax rate to be 26% to 28% of adjusted pre-tax earnings and our cash tax rate to be 18% to 20% of adjusted pre-tax earnings.
Through the first 3 quarters of the year, our commercial and operational execution has generated strong financial results and we expect this to continue in Q4 delivering earnings in the quarter close to last year.
Additionally, we expect our fixed cost absorption to improve by approximately $5 million versus prior year.
Given all this, we expect to see strong earnings growth in Q4 versus prior year with EBIT margins of approximately 15%.
We anticipate composites pricing will improve by mid single digits offsetting the impact of additional inflation and that we should benefit from the recovery of $15 to $20 million of curtailment costs versus 4th quarter 2020.
Overall, we expect to realize strong earnings growth in the quarter versus prior year with EBIT margins of approximately 14% and in roofing, we anticipate the market to finish up for the year, but expect a more difficult comparison to the 4th quarter of prior year with market volumes down mid-teens driven by the expectation for a more normal winter season,;ower storm demand and the likelihood of ongoing supply chain disruptions.
Overall, we anticipate 4th quarter Roofing EBIT margins of approximately 20% on lower volumes and a narrowing but positive price cost mix.
In terms of capital allocation, our priorities remain focused on reinvesting in our business especially productivity and organic growth initiatives returning at least 50% of free cash flow to shareholders over time through dividends and share repurchases and maintaining an investment grade balance sheet.
We hope you will join us in 2 weeks.

Summary:
Financially, we delivered record 3rd quarter revenue of $2.2 billion, an increase of 16% compared with the same period last year and adjusted EBIT of $400 million.
Wwe reported consolidated net sales of $2.2 billion for the 3rd quarter, that's up 16% over 2020 and produced double-digit revenue growth in all 3 segments.
Adjusted earnings for the 3rd quarter were $162 million or $2.52 per diluted share compared to $193 million or $76 per diluted share in the 3rd quarter of 2020.