CSL vs OC: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: OC is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. CSL and OC share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined CSL and OC exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Carlisle Companies Incorporated (NYSE: CSL) is a diversified manufacturer that, after years of portfolio reshaping, has become a focused supplier of building-envelope products that make commercial and residential buildings more energy efficient. It operates through two segments: Carlisle Construction Materials (CCM), which makes single-ply roofing membranes (EPDM rubber, TPO, and PVC), polyiso insulation, and metal roofing and wall systems, and Carlisle Weatherproofing Technologies (CWT), which makes waterproofing, air and vapor barriers, sealants, spray polyurethane foam, coatings, and related moisture-protection products. The company earns most of its revenue from commercial construction, and within that, a large share comes from re-roofing (replacing aging roofs), which is more stable than new construction because roofs wear out on a predictable cycle regardless of the economy.

Full CSL guide

Owens Corning sells three things that go into houses: asphalt roofing shingles, insulation, and doors. Founded in 1938 and headquartered in Toledo, Ohio, it files with the SEC under the plain name Owens Corning, with no Inc. or Corp. attached. Roofing is the biggest and most profitable segment, at ~$1,313 million of second-quarter 2026 sales on a ~34% EBITDA margin, and most of that volume is replacement work: shingles age, storms strip them, and the homeowner reroofs whether or not housing starts are healthy. Insulation, ~$971 million in the quarter, spans fiberglass batts, loose fill, foam sheathing and European stone wool from the Paroc business, and reaches non-residential jobs as well as homes. Doors, ~$513 million, is the Masonite business bought in May 2024. On April 30, 2026 the company closed the sale of its global glass reinforcements operation, retiring the last of the old Composites segment.

Full OC guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• CSL drivers: Commercial re-roofing replacement cycle; Margin expansion and pure-play focus.
• OC drivers: Roofing runs on replacement, not on housing starts; The portfolio was deliberately narrowed to residential.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: Carlisle's end markets are cyclical: commercial and residential construction activity is sensitive to interest rates, credit availability, and the broader economy, and a downturn in construction spending would pressure volumes. For OC, roofing demand is weather-dependent, so a mild storm season removes volume from the segment that generates most of the profit, and the company already warned that second-quarter distributor stocking borrows from the third quarter.

Pick CSL if you believe its drivers more; OC if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the CSL and OC guides.

CSL. Carlisle trades around a low-20s trailing P/E, roughly in line with its own long-term historical median and typical for a high-margin, cash-generative industrial. Because a large part of its earnings power comes from resilient re-roofing demand and steady margin expansion, investors tend to focus on adjusted EBITDA margin, free cash flow, and the pace of buybacks rather than raw revenue growth, which can be lumpy with weather and construction cycles. The Q1 2026 revenue dip was driven largely by poor winter weather that limited roofing installation, while margins still expanded and management reaffirmed full-year guidance for low-single-digit revenue growth.

OC. The headline loss is an accounting artifact of two decisions rather than a description of current trading: the glass reinforcements sale was carried through discontinued operations at a pre-tax loss of ~$175 million for the first half, and Doors took ~$1,135 million of goodwill impairment plus ~$39 million of tradename impairment during 2025. Continuing operations produced ~$660 million of adjusted EBITDA on a ~24% margin in the quarter. Third-quarter guidance calls for ~$2.6 billion to ~$2.7 billion of revenue at a ~20% to ~22% adjusted EBITDA margin, and the quarterly dividend annualizes to roughly ~$3.16 per share, about a ~2.1% yield at recent prices.

Headline figures (approximate, July 2026): CSL shows revenue (ttm) ~$5.0 billion, q1 2026 revenue ~$1.05 billion (down ~4% year over year), q1 2026 adjusted eps ~$3.63 (up ~1% year over year), q1 2026 adjusted ebitda margin ~22.3% (up ~50 bps); OC shows revenue (ttm, continuing operations) ~$9.85 billion, q2 2026 net sales ~$2.76 billion, roughly flat vs ~$2.75 billion, q2 2026 adjusted eps (continuing ops) ~$3.93 vs ~$4.21 a year earlier, net loss (ttm, gaap, incl. discontinued ops) ~-$671 million, or ~-$8.23 per share.

CSL and OC are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined CSL and OC exposure against your real portfolio. It is not an investment adviser.