Antenna size, mount height, ballast requirements, exposure categories — everything you need to spec the right mount and calculate the right ballast for your installation, from a small rooftop camera to a 3.8m satellite dish.
The fundamentals — how these mounts work, why they're the industry default for commercial rooftops, and what makes them engineering-valid.
A non-penetrating roof mount (NPRM) is exactly what it sounds like: a structural mount for satellite antennas, wireless equipment, cameras, and other rooftop hardware that sits on — rather than through — the roof surface. Instead of drilling anchors or lag bolts into the roof structure, an NPRM is held in place entirely by gravity and friction, using concrete ballast blocks loaded into trays on the mount base.
This makes NPRMs the first choice for the vast majority of commercial flat-roof installations. No holes means no water intrusion, no warranty violations for the building owner, no need for a roofing contractor on every job, and no structural engineering review of the roof deck attachment. For facilities managers, that alone is worth thousands of dollars in liability avoidance per installation.
The key engineering principle: ballast resists two distinct forces. Overturning (the mount tipping over in the wind) and sliding (the mount shifting horizontally across the roof). Both need to be calculated independently, and both depend on your specific site conditions — not a one-size-fits-all number from a spec sheet.
Concrete ballast blocks are typically standard 8"×8"×16" CMU blocks weighing approximately 33–35 lbs each. The number of blocks required for your site is determined by a formal engineering calculation — not a rough estimate. Baird's free ballast calculator at ballastcalc.com uses ASCE 7-10 wind load methodology to give you a defensible, site-specific answer.
NPRMs also serve well in ground applications where in-ground installation is cost-prohibitive or logistically impractical — parking lots, paved surfaces, temporary deployments, or locations where running conduit to a true foundation doesn't pencil out. In those cases, the rubber roof pads are simply omitted and the mount sits on the compacted surface.
Before you look at a single product page, answer these five questions in order. Every question narrows your options until the right mount is obvious.
Antenna diameter (for parabolic dishes), effective projected area in square feet (for flat panels, cameras, wireless gear), or pole frontal area. This single number drives your entire ballast calculation. A 0.9m dish is roughly 8 sq ft. A 2.4m dish is roughly 46 sq ft. A PTZ camera may be just 1–2 sq ft.
Height clears obstructions, brings antennas into line of sight, or elevates cameras. But taller = more wind moment arm = more ballast required. Know the minimum height before sizing up. Heights typically range from 2.5' to 15' across the Baird NPRM line, with specialty configurations reaching higher.
Exposure B (sheltered suburban), C (open terrain), or D (coastal/waterfront). This is the single biggest multiplier in the ballast calculation. Coastal Exposure D can require 2–3× more ballast than the same mount in suburban Exposure B. Your zip code plus a terrain description determines this.
Taller buildings experience higher wind speeds at the roofline. The ASCE 7 basic wind speed for your location (available from ASCE hazard maps or at ballastcalc.com) combines with building height to determine velocity pressure at the antenna centerline.
A ballasted mount concentrates weight on a small footprint. A larger-base mount (like the B4-6x6 vs the B3-34x40) spreads that weight over more area and reduces PSF load. If your roof has a low load rating, footprint size may drive your selection as much as antenna size does.
Mount sizing starts with what you're hanging on it. Here's how to translate your equipment into the spec numbers that drive every downstream decision.
Dish size in meters (0.9m, 1.2m, 1.8m, 2.4m, 3.1m, 3.8m) is the standard spec. The critical ballast variable is effective wind area — the frontal surface area the wind actually pushes against. For a solid dish, this is roughly 85–90% of the geometric dish area.
Flat-panel wireless antennas, sector antennas, PTZ cameras, and measurement equipment each have a manufacturer-specified effective projected area (EPA) in square feet. If not available, calculate it from the equipment's maximum dimensions. Key examples:
Mast OD (outer diameter) matters for larger satellite dishes. Manufacturers specify the required mast OD for their mount adapters — for example, Prodelin 1382/1383 requires a 10.57" OD mast, while the PXL-2 uses 6.62" OD as its most popular configuration (with up to 6.62" Sch. 80 available on the PXE for high wind area applications). Always confirm mast OD compatibility between your antenna and mount before ordering. Baird's product pages list mast OD for every NPRM configuration.
Height is the second variable in every ballast calculation — and more height always means more required ballast, everything else being equal.
Mount height affects ballast in two ways. First, a taller mast places the antenna's wind load farther from the base, increasing the overturning moment. Second, a taller mast means the centerline of the antenna is at a higher elevation above grade — and higher elevation means higher wind velocity per ASCE 7 velocity pressure coefficients.
Choose the minimum height that achieves your installation objectives:
As a general guide: doubling the mount height roughly doubles the overturning ballast requirement, all other variables held constant. A 10' mount in Exposure C may need twice as many blocks as a 5' mount carrying the same antenna. Always run the calculator — don't estimate.
Exposure category is the single most impactful variable in your ballast calculation — more than building height, more than antenna size. Getting this right is not optional.
ASCE 7 defines three terrain exposure categories based on the surface roughness of the land upwind of your building. Rougher terrain (trees, buildings, terrain features) slows the wind and reduces effective load. Smoother terrain (open fields, water) accelerates the wind and dramatically increases load.
Urban and suburban areas, wooded terrain, or surface irregularities 20 feet or more in height covering at least 20% of the area. Lowest wind multiplier.
Open terrain with scattered obstructions having heights generally less than 30 feet. Flat open country, grasslands. Most common category for commercial rooftops.
Unobstructed areas and water surfaces outside hurricane-prone regions. Flat, open terrain within 1,500 feet of large bodies of water. Highest wind multiplier.
Illustrative multipliers for a typical rooftop installation at 30 ft building height. Actual values depend on wind speed, antenna area, and mount height. Use ballastcalc.com for site-specific calculations.
When in doubt about your exposure category, use the more conservative (higher) classification. Coastal installers should virtually always select Exposure D. If your building is in an open commercial area — a large parking lot, an airport, a warehouse district — Exposure C is almost certainly correct even if you're not on the coast.
"In an exposed coastal area, you'll probably want to select Exposure C or Exposure D. The calculator will give you an exact ballast weight with printable documentation you can share with building owners, engineering firms, or local officials."— Baird Mounting Systems FAQ, B4-4x4 product page
Once you have your five inputs, plug them into ballastcalc.com. Here's exactly what the calculator needs and what you'll get out of it.
Baird's free online ballast calculator at ballastcalc.com implements the ASCE 7-10 methodology for calculating required ballast weight on non-penetrating roof mounts. It handles all the math — velocity pressure, gust factors, overturning moments, sliding resistance — and outputs a specific weight recommendation with documentation you can download and share.
Your city and state. Determines the ASCE 7 basic wind speed (mph) for your region. Coastal areas are dramatically higher than inland sites.
B (suburban), C (open), or D (coastal/waterfront). The single biggest multiplier in the calculation — don't guess this one.
The height of your roof above grade. Higher buildings experience higher wind speeds — the calculation accounts for the ASCE 7 velocity pressure coefficient Kz.
Effective projected area of your antenna in square feet. For parabolic dishes, typically 85–90% of the geometric area. Use the manufacturer's wind load spec when available.
The height of the mast from the base to the antenna centerline. Taller installations increase the overturning moment arm and require more ballast.
Surface type affects the friction coefficient used in the sliding calculation. TPO, EPDM, gravel, and concrete each have different friction values. The calculator includes these options.
Input your six site variables and get an exact ballast weight requirement — with printable PDF documentation you can give to building owners, engineering firms, or permit authorities. Based on ASCE 7-10. No account required.
Open Ballast CalculatorThe output gives you separate ballast requirements for overturning and sliding, expressed in total pounds and approximate block count. The printable report is formatted for presentation to building owners, permit authorities, and structural engineering review — an important differentiator when professional documentation is required.
How the ballasted weight distributes across the roof surface matters just as much as the total weight — especially on older or lightly-constructed buildings.
Every commercial roof has a rated live load capacity expressed in pounds per square foot (PSF). A typical commercial flat roof is rated at 20–30 PSF. The ballasted mount must keep its weight below this limit across the footprint it occupies.
This is where footprint size becomes a selection criterion, independent of antenna size. The B3-34x40 has a 34"×40" footprint (~9.4 sq ft). The B4-4x4 spreads the same weight over a 48"×48" footprint (~16 sq ft). If the total ballast weight is 500 lbs:
Illustrative example: 500 lbs total load distributed across each mount's base footprint. Actual load calculations must account for mount weight, ballast weight distribution, and block placement.
If your ballast calculation requires heavy loading on a lower-rated roof, step up one mount size to spread the load across a larger footprint. The jump from B3-34x40 to B4-4x4 cuts PSF by ~40% with the same ballast load. Moving to the B4-6x6 can cut it by another ~50%.
Baird's ballast calculator includes PSF output specifically to help with this check. If your roof structural drawings are available, confirm the allowable live load with the building's structural engineer before finalizing your mount selection — especially on older structures or buildings with deferred maintenance.
Every non-penetrating roof mount in the Baird line — organized by application category, with key specs and direct product links.
For pitched and gabled roofs, a flat-base NPRM isn't the right tool. Baird's Peak Roof Ridge Mounts are a non-penetrating solution purpose-built for residential and commercial sloped roofs — and they're among the most popular products in the entire Baird line.
Standard NPRMs are engineered for flat and low-slope roofs — typically under a 3:12 pitch. If your building has a peaked, gabled, or steeply pitched roof, a flat-base mount will not sit level, and ballast blocks will shift or slide. The result is a structurally compromised installation.
Baird's Peak Roof Ridge Mounts straddle the ridge line of the roof and clamp securely to the peak without drilling, cutting, or breaching the roofing surface. Like all Baird NPRMs, they are hot-dip galvanized after fabrication and carry a 10-year warranty.
Peak Roof Ridge Mounts are popular enough to warrant their own detailed guide — covering pitch measurement, product selection, installation steps, and compatible antenna types. A dedicated post is planned; in the meantime, browse the full peak ridge mount product line or contact Baird engineering with application questions.
Every Baird NPRM in one table. Use this to cross-check your antenna size, height need, and footprint requirement.
| Model | Base Footprint | Height Range | Max Antenna | Typical Application |
|---|---|---|---|---|
| Compact — Cameras, Wireless & Small Satellite | ||||
| B3-34x40 | 34" × 40" | 2.5' – 10' | 1.0m satellite | Cameras, WiFi, small satellite, Starlink |
| B4-4x4 | 48" × 48" | 2.5' – 10' | 1.2m satellite | Cameras, wireless, small/medium satellite |
| B4-6x6 | 72" × 72" | 3' – 15' | 1.2m satellite | High mast clearance, exposed locations |
| Camera Mounts | Varies / 10'×10' | 2.5' – 30' | Camera / PTZ | Security cameras, surveillance, time-lapse |
| Mid-Range — 1.8m to 2.4m Satellite & Microwave | ||||
| B6-116 | 10' × 10' | 5' – 10' | 1.8m satellite | 1.8m earth stations, microwave, point-to-point |
| B6-116 Ka | 10' × 10' | 5' only | 1.8m Ka-Band | 1.8m Ka-Band satellite links (Hughes, ViaSat) |
| VL-4 | Varies | Custom | 2.4m satellite | Low elevation angle, CPI SAT / Global Skyware 243 |
| Large Commercial — 3.1m to 3.8m Satellite | ||||
| PL-2 | Large platform | Standard | 3.1m | Large C/Ku-Band earth stations, 1–3 trays |
| PL-2 Ka | Large platform | Standard | 2.4m Ka-Band | Ka-Band earth stations |
| PXL-2 | Extended platform | Standard | 3.7m | Large Ku-Band, 2–4 trays, 6.62" mast (most common) |
| PXH | Extended platform | Standard | 3.8m | GD Satcom / Prodelin 1382, 1383, 1385 |
| PXE | Extended platform | Standard | 3.8m | Large wind area equipment, high wind / Exposure C–D sites |
| AFC | Extended platform | Standard | 5.0m+ / Towers | Largest earth stations, rooftop tower bases, 1–4 trays |
| Specialty — Wireless Infrastructure | ||||
| Sector Frame | 14' face frame | 5' masts | Sector antennas | CBRS, LTE, 5G small cell multi-sector deployments |
All Baird NPRMs are hot-dip galvanized after fabrication, designed and manufactured in Cedar Falls, Iowa, USA, and backed by a 10-year warranty. Browse full product catalog →
Run through this before ordering. Every item here has the potential to change your mount selection or ballast requirement.
Baird's engineering team supports ballast calculations and mount specification for any installation. Contact them at bairdmounts.com/contact or at [email protected]. For complex or high-stakes installations, this is always worth the call.
The questions Baird's engineering team hears most — answered straight.
Running the calculation saves time and money in both directions — not just when you need more ballast than expected, but especially when you need less. Many installations in sheltered locations (Exposure B), at low building heights, or with small-footprint equipment simply don't require full trays. If you skip the calculation and just fill everything, you may be hauling and placing significantly more concrete than the site actually demands. On a rooftop job, unnecessary blocks mean unnecessary trips, unnecessary roof loading, and unnecessary cost.
For example, a B4-4x4 with a small wireless antenna at 30 feet in a suburban location may only need a fraction of its tray capacity. The same mount on a 10-story coastal building with a 1.2m dish in Exposure D will need every block it can hold. The only way to know which situation you're in is to run the numbers. Ballastcalc.com takes under five minutes and tells you exactly how many blocks you need — no more, no less.
That said, for tall buildings, coastal sites, open-terrain locations (Exposure C or D), large antennas, or high mast heights, a proper calculation isn't optional. The consequences of an under-ballasted mount failure — equipment damage, roof damage, liability — far outweigh the time spent on the calculation.
Yes — all Baird NPRMs work equally well as ground mounts. For ground mounting, simply omit the rubber roof pads and ensure the surface is level and compacted. No concrete foundation is required. Ground mounting is common for sites where running in-ground conduit is cost-prohibitive, for temporary deployments, or in parking lots and paved areas.
Note that ground-level installations are often in Exposure C or D conditions with nothing to shelter the mount. Run your ballast calculation using ground level as your "building height" (1–2 feet) and your site's appropriate exposure category.
Both are compact NPRMs for small antennas, cameras, and wireless gear, and both support heights from 2.5' to 10'. The core difference is footprint: the B3-34x40 has a 34"×40" base, while the B4-4x4 has a larger 48"×48" base.
The B4-4x4's larger footprint means: (1) it can hold more ballast blocks if your site requires extra weight, and (2) it distributes the same ballast weight over more roof area, reducing pounds-per-square-foot loading. Use the B3-34x40 for sheltered sites with lower ballast requirements. Step up to the B4-4x4 if your ballast calculation comes in high, if your roof PSF rating is tight, or if you're in an exposed coastal location. The ballastcalc.com output will often make the decision clear.
Higher buildings experience higher wind speeds at the roofline. ASCE 7 accounts for this through the velocity pressure exposure coefficient (Kz), which increases with height above ground. The formula is roughly: wind pressure increases with the 2/7 power of height ratio.
Practically speaking, the same mount and antenna combination on a 30-story building requires meaningfully more ballast than on a one-story warehouse — often 30–50% more for a 200-foot building vs. a 30-foot building. Ballastcalc.com automatically accounts for this — just enter your building height accurately.
NPRMs are designed for flat and low-slope roofs (typically under 3:12 pitch). For steeper pitched roofs, peak/ridge mounts are the correct solution. Baird offers a dedicated Peak Roof Ridge Mount line — see the section above, or browse the full Roof Peak Ridge Mount product page. Do not attempt to use a flat-base NPRM on a sloped roof — the mount will not sit level and ballast will shift, compromising structural integrity.
The ballastcalc.com calculator produces a downloadable, printable report that includes: your site inputs, the ASCE 7-10 calculation methodology, separate overturning and sliding ballast requirements, the recommended number of concrete blocks, and the PSF loading figure for your mount. This documentation is formatted to present to building owners, structural engineers, and permit authorities. It does not constitute a licensed engineering stamp, but it provides the calculation basis needed to support one.
All Baird non-penetrating roof mounts carry a 10-year product warranty. All mounts are hot-dip galvanized after fabrication (not pre-galvanized components — post-fabrication dip) for maximum corrosion protection across the full weld surface. Baird designs and manufactures all products in Cedar Falls, Iowa, USA.
Yes — rubber roof pads are included with every Baird NPRM purchase and are sized to fit under every part of the mount that contacts the roof surface. The pads serve two purposes: protecting the roof membrane from abrasion, and providing the friction interface that the sliding calculation relies on. The friction coefficient for rubber-on-roofing-membrane is included in the ballastcalc.com calculation when you select your roof surface type.
Run your site through the free ballast calculator, browse the full NPRM product line, or reach out to Baird's engineering team for support on complex or custom installations.