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

Same yardstick, side by side (as of September 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. GFF 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 GFF 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.

Griffon Corporation is a diversified management and holding company that, after a multi-year portfolio overhaul, operates primarily as a North American building products manufacturer. Its Home and Building Products segment makes residential garage doors under the Clopay brand, commercial sectional doors, rolling steel doors and grilles, and residential and commercial ceiling fans through Hunter Fan, which Griffon acquired in 2022. Products reach the market through professional dealers and installers as well as big-box home centers, so demand tracks a mix of new residential construction, repair and remodel activity, and non-residential building.

Full GFF 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.

• GFF drivers: Pure-play building products focus; Price and mix over volume.
• 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: Griffon's earnings are now concentrated in a single end market, so a prolonged downturn in U.S. 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.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick GFF 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 GFF and OC guides.

GFF. GFF traded near $103 in early August 2026 after a sharp post-earnings move, putting it around 26 times trailing and roughly 18 times forward earnings, with a dividend yield near 0.9%. Trailing revenue of about $2.56 billion still reflects the AMES businesses now moving to joint ventures, so the roughly $1.8 billion continuing-operations guide is the cleaner run-rate. The gap between those two figures is the main reason headline valuation screens can be misleading for this name right now.

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, August 2026): GFF shows q3 fy2026 revenue ~$481M (+7% YoY), q3 fy2026 adjusted eps ~$1.51 (vs ~$1.39), fy2026 revenue guidance (continuing ops) ~$1.8B, fy2026 adjusted ebitda guidance ~$458M; 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.

GFF 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 GFF and OC exposure against your real portfolio. It is not an investment adviser.