The Lomanco 135 roof vent is a roof-mounted attic ventilation product, but exact specifications can vary by product version and retailer listing. Before choosing or installing one, homeowners should confirm the model number, material, dimensions, and net free area (NFA) on the product label or manufacturer documentation. Proper attic ventilation also depends on balanced intake and exhaust—not simply the number of roof vents.
What Is a Lomanco 135 Roof Vent?
A roof vent provides an opening for air to leave an attic or roof space. Lomanco makes several types of residential ventilation products, including roof louvers, ridge vents, and wind-driven turbines. The number “135” identifies a particular model or listing, but it should not be treated as a universal specification without checking the packaging or current Lomanco product information.
That distinction matters when comparing products. Two vents can look similar but differ in their opening size, weather protection, construction, and rated NFA. Retailer descriptions may also omit details or use shorthand. A reliable product match starts with the full model designation and the manufacturer’s installation instructions.
The vent’s intended use should also be confirmed. A roof-mounted exhaust vent is generally part of an attic ventilation system. It is not automatically suitable for venting a bathroom fan, kitchen exhaust, or clothes dryer. Those appliances need an approved duct route to the exterior, and their exhaust should not be discharged into an attic.
How to Confirm the Vent’s Specifications
Before buying a Lomanco 135 roof vent or planning a replacement, check the product label, carton, installation sheet, or manufacturer’s official product information. Record the following details:
- Full model number: Confirm that “135” is the complete model reference, not a size, color, or abbreviated listing.
- Net free area: NFA is the effective area available for airflow after screens and internal obstructions are accounted for. It is usually stated in square inches.
- Dimensions and roof opening: The required cutout can differ from the vent’s outer flange dimensions.
- Material and finish: Verify whether the product is metal, plastic, or another material, and whether its finish suits the roof and local conditions.
- Roof compatibility: Check the approved roof pitch range, roofing type, and installation details.
- Code and warranty information: Follow applicable local requirements and the manufacturer’s conditions for installation.
If the vent is already installed, its model may be printed on a label underneath the cap or visible from the attic side. Access should be safe; walking on a roof can be hazardous, and disturbing shingles or flashing may cause leaks. A roofing contractor can identify the product when its label is inaccessible.
Why Net Free Area Matters
NFA, rather than the vent’s outside dimensions, is the useful figure for estimating ventilation capacity. A grille, screen, or internal baffle reduces the portion of the opening through which air can pass. Manufacturers rate vents to account for these restrictions, so using the specified NFA is more reliable than measuring the visible opening.
U.S. building codes commonly use a ventilation ratio of 1 square foot of net free ventilation area for every 150 square feet of attic floor area. A reduced ratio of 1:300 may be allowed when qualifying conditions are met. Those conditions typically include a balanced distribution between high and low vents and other requirements in the adopted code. Requirements can vary by jurisdiction, so local building officials should be consulted.
For a basic estimate, divide attic floor area by 150 or 300, as applicable, to find the total NFA required in square feet. Multiply by 144 to convert square feet to square inches. The result is the combined area for intake and exhaust—not the amount needed from roof exhaust vents alone.
Example: A 1,500-square-foot attic using the 1:300 ratio would require 5 square feet, or 720 square inches, of total NFA. A balanced design would generally allocate about half to intake and half to exhaust. The exact design must account for the home’s layout, existing vents, roof geometry, and local code.
Once the manufacturer’s NFA for the Lomanco 135 is confirmed, a designer can estimate the number needed by dividing the required exhaust area by the NFA per vent. The calculation is only a starting point: vent placement and intake capacity matter just as much as the total.
Balanced Attic Ventilation: Intake and Exhaust
Most conventional vented attics rely on lower intake openings—often soffit or eave vents—and higher exhaust openings near the roof peak. Air can enter low and leave high as outdoor conditions and wind create pressure differences. The precise airflow pattern is not guaranteed, but a well-designed system gives air a suitable path through the attic.
A roof vent such as the Lomanco 135 may serve as an exhaust component, depending on the model’s design and installation instructions. It should not be added without checking the existing system. If the attic lacks adequate intake, an exhaust vent may draw replacement air through unintended paths, such as gaps around attic hatches or interior walls. That can reduce performance and potentially move conditioned air into the attic.
Mixing exhaust types can also create problems. For example, a high roof vent and a ridge vent may compete for airflow, allowing one exhaust opening to pull air backward through another. Before adding a vent, identify existing ridge, gable, roof, and soffit openings. A roofing or ventilation professional can assess whether the system is balanced and whether openings should be added, sealed, or reconfigured.
Choosing the Right Number and Location
The correct number of vents depends on the verified NFA per unit and the attic’s total ventilation requirement. It also depends on whether the vents are intended to provide all exhaust or supplement an existing system. A calculation based on an assumed model rating can lead to too few vents—or excessive, poorly balanced exhaust.
Placement should follow the manufacturer’s directions and suit the roof structure. Roof vents are commonly distributed across the roof rather than concentrated in one small area. Installers must avoid rafters, wiring, plumbing, and other obstructions, while maintaining proper clearances from roof edges and ridges as required by the product instructions and local code.
Roof shape influences the layout. Hips, valleys, dormers, and multiple attic compartments can interrupt airflow, and a single vent pattern may not serve every enclosed space. Some areas may need separate ventilation. An attic with a cathedral ceiling, a finished roofline, or a sealed unvented design requires a different approach from a typical open attic.
General Installation Considerations
Installation details are model-specific. The manufacturer’s instructions take precedence over generic guidance, particularly for the opening dimensions, roof-pitch limits, fastener type, and flashing method. The following overview is not a substitute for the product instructions or professional installation.
- Inspect the attic and roof: Confirm the vent’s intended location, available airflow path, roof condition, and clearance from framing and utilities.
- Verify the layout: Check that the proposed exhaust area is appropriate for the attic and balanced with intake. Identify existing vents before cutting.
- Mark the opening: Use the specified cutout dimensions and position. Do not use the vent’s exterior footprint as the cutout size unless the instructions say to do so.
- Cut carefully: Protect the attic from debris and avoid damaging roof framing, wiring, or other building components.
- Fit and flash the vent: Follow the prescribed sequence for shingles, underlayment, flashing, and fasteners. Incorrect flashing is a common source of roof leaks.
- Check the finished work: Confirm that the vent is secure, the opening is clear, and surrounding shingles and flashing shed water correctly.
Roof work involves fall risks and can damage shingles if performed incorrectly. Steep roofs, wet or icy conditions, fragile roofing, and uncertain framing are reasons to hire a qualified roofing contractor. Homeowners should also check permit requirements and preserve documentation for any warranty claim.
Common Problems and What They May Indicate
Moisture or mold in the attic is not proof that the roof vent is too small. Possible causes include insufficient ventilation, blocked soffit vents, air leakage from the living space, a roof leak, or high indoor humidity. A full inspection should distinguish among these issues before vents are added.
Excessive heat in the attic can relate to ventilation, but ventilation alone does not correct inadequate insulation, duct leaks, or air-conditioning problems. Sealing air leaks between the home and attic and maintaining insulation are important parts of a broader energy and moisture strategy.
Water stains near a vent may point to damaged flashing, improperly installed shingles, condensation, or another roof defect. The vent should be inspected from both the roof and attic sides. Simply applying sealant over the exterior is not a dependable repair unless the manufacturer’s instructions call for it.
Weak airflow may result from blocked intake, insulation covering soffit openings, a closed or obstructed vent, or an attic layout that does not allow air to move freely. Adding more exhaust vents without identifying the restriction can fail to solve the problem.
Lomanco 135 Roof Vent Compared With Other Vent Types
| Vent type | Typical role | Key consideration |
|---|---|---|
| Roof louver or static roof vent | Provides a fixed exhaust opening through the roof | Confirm rated NFA, flashing details, and placement |
| Ridge vent | Provides continuous exhaust near the roof ridge | Works with suitable intake and the correct ridge installation |
| Gable vent | Provides ventilation through a gable wall | May not ventilate all roof areas evenly, depending on the attic |
| Turbine vent | Uses wind to help move air through a roof opening | Requires appropriate installation and a balanced system |
The comparison is functional, not a claim that every Lomanco 135 listing has the same construction or capacity. Product labels and official specifications should be checked before comparing NFA, price, or compatibility across vent types.
Buying and Maintenance Tips
When shopping, compare the full model number, NFA, opening dimensions, material, finish, roof-pitch range, and included installation instructions. Confirm that the vent is intended for the roofing material and exposure conditions. If a replacement is needed, matching the old vent’s appearance is not enough; the new product must also fit the opening and maintain proper weather protection.
Inspect roof ventilation during routine roof maintenance, ideally from a safe location or with professional help. Look for loose fasteners, damaged flashing, debris, blocked openings, corrosion, and signs of water intrusion. From the attic, check for daylight around unintended gaps, damp insulation, staining, and clear paths from intake vents. Avoid blocking soffit vents with insulation; baffles can help maintain an airflow channel where appropriate.
Frequently Asked Questions
How many Lomanco 135 roof vents are needed?
There is no dependable universal count. The calculation requires the attic area, applicable ventilation ratio, verified NFA for the exact model, existing intake and exhaust, and any code requirements. A balanced design is essential.
Can a Lomanco 135 vent be installed on any roof?
Not necessarily. Roof pitch, roofing material, framing, product dimensions, and manufacturer restrictions all affect compatibility. Check the installation sheet before purchase or cutting the roof.
Does a roof vent replace soffit vents?
No. A roof exhaust vent does not provide the low intake capacity typically needed for balanced ventilation. The entire system should be evaluated together.
Where can the exact NFA be found?
Look for the rating on the product packaging, installation instructions, or Lomanco’s official product documentation. If the model identity is uncertain, contact Lomanco or a supplier with the label or product photos rather than relying on a generic online listing.