Railed vs. Rail-less mounting for rooftop solar projects
If you intend to install a solar panel on your roof, you must first decide on the type of mounting system you want.
Although there are different mounting options on the market, the most common ones are railed and railless systems.
Knowing the difference between these two types of mounting is key to making the right choice for your project.
Railed systems employ metal rails that are screwed to the roof, whereas railless systems are attached directly to the roof’s surface.
The use of a rail reduces the amount of drilling on the roof while allowing for future roof maintenance. However, both systems are widely used and excellent choices.
The decision on which type of mounting system to use will be influenced primarily by the following factors:
- Roof material (tile, metal/composite shingles),
- The amount of space on the roof,
- The type of roof (flat or pitched roof),
- Solar panel tilting expectations,
- Expected roof maintenance issues,
- The size of the solar panels,
- Future expansion plans for the system,
Most solar installers will have their preferences when it comes to railed and rail-less mounting systems. In most cases, they will likely recommend the system that they are most familiar with.
However, what your installer recommends may not be the system that is best for your solar project.
It’s important to weigh all of the factors and decide which one you think will work out the best.
Railed mounting systems
A railed mounting system as its name suggests is a system that has rails that are mounted on the roof. The rails serve as a guide for the solar panel and reduce the amount of drilling that is otherwise required.
With these systems, solar panels are mounted to the roof with metal rails and can be adjusted for different slopes in your roof. The goal of the rail is to allow you to install, adjust or remove solar panels easily, without damaging your roof.
The rails also provide an opportunity to add future modules when your energy needs increase in the future. However, this is not all that a railed system offers.
The rails are usually attached to the roof using screws or bolts that need to be drilled into the structure of your home.
Railed systems usually consist of:
- A set of aluminum tracks (rails),
- The mounting structure which holds onto your roof’s tiles, and
- A set of aluminum crossbars to hold your solar panels in place.
Although the rails are often made of aluminum, they can also be made of stainless steel or galvanized metal depending on the manufacturer and the specific system.
The rail system elevates the solar panel above the roof, leaving clearance for roof maintenance and snow removal. If you notice a leak in your roof, having the solar panel attached to a railed system will allow you to access the roof without any difficulties.
If you choose a rail system with a tilting bracket, you can easily adjust the angle of your solar panel to accommodate for seasonal changes in sunlight. This way, you can increase the amount of power you generate throughout the year.
For most solar projects, the railed mounting system is an excellent choice as it provides a sturdy foundation for your solar panels.
Types of railed mounting systems
There are many different types of rail systems that you can choose from. However, we are going to focus on the most common types.
Fixed-tilt rail systems
Fixed-tilt rail systems are the most common type of railed mounting system. They are designed in a way that allows your solar panel to remain at one fixed angle, without any tilting capabilities.
While these systems are fairly simple in design, they provide a sturdy foundation that can support the weight of your solar panel.
Adjustable-tilt rail systems
Adjustable-tilt rail systems allow adjusting tilt by attaching a tilting mechanism to the rails. Although adjusting the tilt of solar panels is desirable, manual adjustment of tilt angle only offers a limited degree of flexibility.
Multi-axis rail systems
There are also multi-axis rail systems that allow the solar panels to be adjusted in three different dimensions.
Although these types of rail systems are more expensive than other railed mounting options, they offer excellent versatility when it comes to installation.
Multi-axis rail systems are typically used on large commercial solar projects where the use of sophisticated mounting options is necessary for maximizing solar energy production and accommodating future expansion.
Rail-less mounting systems
Rail-less mounting system as its name suggests is placed directly on the roof without rails.
It is a more low-profile mounting approach. Systems generally utilize several attachment points on the rooftop and connect each panel one at a time, eliminating the need for rails.
Most rail-less systems will require more drilling than railed systems, which will create holes in your roof. As a result, your roof will have an increased risk of water damage.
Another disadvantage is the difficulty in gaining access to the roof for maintenance and snow removal, which can be a problem if you need to access the roof.
If you need to access a point beneath a solar panel, you must first remove the panel(s), which can be inconvenient.
Railed versus rail-less mounting systems
Installation of a railed system is generally easier than that of a rail-less one. Most roofing professionals will be able to install a railed system quickly and easily.
Installing rail-less systems, on the other hand, requires more expertise in roof installation.
This is because you will need to drill more holes in your roof, and you will need to have a detailed knowledge of roofing, including the various layers of your roof.
Every roof needs proper maintenance, regardless of whether it has a solar panel system or not.
When you have an attached railed system, you can gain easy access to all parts of your roof simply by removing the solar panels. This makes it easier to inspect and maintain your roof.
In the case of a rail-less system, you will not be able to access the roof as easily.
You need to remove the solar panels in order to access the roof. If you have a rail-less system and your roof is leaking, it will require more time to access your roof and make repairs.
If you are concerned about future repairs, railed mounting system would be the preferred option.
Having a railed system is beneficial because you can detach the solar panels before removing snow from your roof.
As a result, you will have an easier time removing snow from your roof and there is no risk of damaging the solar panels or any other components of your solar panel system.
In the case of a rail-less system, you will need to remove the panels in order to clear snow from your roof. This is more time-consuming and may risk damaging your system depending on how much snow you need to remove.
The cost of a mounting system in solar PV installations is generally not a major consideration. Because solar PV systems are already expensive on their own, and mounting systems are a relatively tiny part of the overall cost.
There are two types of costs associated with railed and rail-less mounting systems. They are material costs and labor costs.
Material cost for both types of systems is generally the same, but it can be slightly higher with a railed system because of the additional materials required.
However, the railless system will require more time for installation, which will increase labor costs.
As you can see both types of mounting systems have their own respective advantages and disadvantages, depending on which type of system you need.
A railed mounting system is generally the best option for a rooftop solar project because it allows you easy access to your roof, which provides peace of mind.
A rail-less system requires more expertise in roof installation and has a higher risk of water damage.
All in all, it’s important to consider all factors when deciding which type of system is best for your project. The right mounting system should be determined based on the specific needs and requirements of each rooftop solar installation.