Single-lock vs. double-lock
| Single-lock (90°) | Double-lock (180°) | |
|---|---|---|
| Fold | The seam is folded over once | The seam is folded over twice |
| Water | Very good on moderate slopes | Best; used where water may sit at the seam |
| Wind | Higher than snap-lock | Highest uplift resistance of the standing seam types |
| Typical use | Homes and light commercial | Low-slope commercial, long runs, exposed sites |
General characteristics. Ratings and minimum slopes come from each panel's published data.
Where we recommend it
- Low slopes: porches, additions and commercial roofs below what snap-lock is rated for. Some mechanically seamed systems are published for slopes as low as 1/4:12; we confirm the minimum for the exact panel we quote.
- Long runs: warehouses, storage buildings and long ranch roofs, on floating clips that let panels expand and contract
- Exposed sites: open land and lake lots where wind uplift drives the design
- Retrofits: new standing seam over an old metal building on new framing. See metal retrofit.
Fixed and floating clips
Steel grows and shrinks with Texas heat and cold, and a long panel moves more than a short one. Floating clips let the panel slide while it stays locked down. The panel is usually pinned at one point, often the ridge or the eave, so the movement goes the right way. Get this wrong and it shows up later as torn clips, popping noises and stressed trim.
Seam sealant
Many low-slope mechanically seamed systems call for a sealant bead inside the seam, applied before it's seamed. When the panel manufacturer or the warranty requires it, we follow that spec.
Why owning the equipment matters
Long runs are hard to ship, and the panel has to suit the seam it's locked into. We form panels on our own roll formers and standing seam machine, cut to the measured length of each run, and our own crew installs them.
What sets the price
- Single- or double-lock, and seam height
- Gauge (24 or 26) and paint system
- Clip type and spacing for your wind exposure
- Deck or framing, insulation and underlayment
- Panel length, access and lift equipment
Manufacturer NDL (no-dollar-limit) warranties, such as a 20-year NDL, are available depending on the product and the warranty purchased, and are issued after the manufacturer's own inspection. Compare with snap-lock standing seam.
More metal: snap-lock standing seam · mechanically seamed · commercial R-panel · 26 gauge · roll-formed to length · retrofit over an existing roof · back to metal roofing
Commercial warranty: a workmanship warranty from 10 years up to lifetime, depending on the job, plus 10- to 20-year NDL (no-dollar-limit) manufacturer warranties. Manufacturer coverage depends on the product and brand, and on the project qualifying for that manufacturer's program. We put the exact warranty for your roof in writing.
Certified, with 30 years installing every major roofing brand, a family roofing business going back 75 years, and over $80 million in completed roofing projects. 5.0 stars on Google at all three of our offices.
Request a free inspection or call (817) 733-9228. Small repairs are welcome too.