Free tool · Pre-install checklist
Solar panel weight & attachment planner
Before you sign a solar contract, know what the array actually weighs, how much wind uplift the roof will see, and how many lag bolts your rafters need. If your installer can't answer these three questions, get a second bid.
Your array
Panel model
Panel count
System size: 8.8 kW DC
Roof pitch (rise / 12)
5/12 pitch ≈ 23°
Rafter spacing
Wind exposure
Most ABQ homes are Exposure C. Sandia foothills and West Mesa ridges are D.
Load report
Total dead load
1,590 lb
3.79 psf over 420 sqft
IRC live-load check
PASS
Under 5 psf rule of thumb
Uplift · corner
40.3 psf
Zone 3 ASCE 7-22
Uplift · field
25.9 psf
Zone 1 mid-roof
Attachments (lag bolts into rafters)
121
Minimum count with 15% safety factor. Spec: 5/16" × 4" stainless lag through flashed L-foot into rafter, EPDM-gasket washer. Rail length ordered: ~130 ft.
Numbers are pre-design estimates for NM (Vult = 115 mph, Risk Cat II). A stamped structural report is still required for permit — this tool tells you if your installer's numbers pass the sniff test.
What installers gloss over
Three questions to ask before you sign.
"Will my rafters take the load?"
A 20-panel array is ~1,300 lb spread over 420 sqft — usually fine on 2x6 @ 24" o.c. But 30+ panels on undersized 2x4 rafters needs sistering.
"How is the array flashed?"
Every lag penetration is a leak risk. Insist on QuickMount PV or IronRidge FlashFoot 2 — not just butyl tape.
"Are you re-roofing under the array?"
If your shingles have <10 yrs left, re-roof BEFORE solar. Removing/reinstalling an array to re-roof later costs $2,000–$4,000.
Next step
Roof + solar package? We coordinate with 6 NM installers and warranty every penetration for life.
Book the free on-site inspection, or send a photo and we'll tell you what to do next. No sales pitch — we don't install roofs.