Solar Panel Spacing Gaps (Why They Are Important)

If you’ve decided to put solar panels on your rooftop, you should know there’s a right and wrong way to do this.

First of all, you have enough room on your roof for the panels, but you also have the right amount of space between each panel.

Keep reading to find out how much space we’re talking about and why it’s necessary in the first place.

How Much Gap Should Be Under a Solar Panel?

The solar panels should never be flush with the roof. This is because, on very hot days, the heat generated can leak through to your attic and cause it to overheat.

Therefore, most manufacturers recommend a gap of four inches between the panels and the roof itself.

How Much Gap Should Be Between the Solar Panels and the Roof?

The gap between the last row of solar panels and the roof’s edge should be a minimum of 12 inches or one foot.

This ensures the panels are accommodated as they expand and contract during the day.

See also: Mounting Solar Panels: A Complete Beginner’s Guide to Installation

How Much Gap Should Be Between Two Solar Panels?

It is best to leave four to seven inches of space between two solar panels. Again, this accommodates the solar panels’ expansion and contraction during the day.

How Much Gap Should Be Between Solar Panel Rows?

The gap between solar panel rows should be around five to six inches, but it is also recommended that you leave one to three feet of space between every second or third row.

This is because maintenance workers need enough room to get on the roof and make repairs whenever necessary.

What About Flexible Solar Panel Air Gaps?

Flexible solar panels are used on cars, RVs, boats, and so on, and they are sometimes installed directly onto the surface of these devices without an air gap between them.

Studies in Australia and other countries have proven that when flexible solar panels are placed next to one another, with one set having an air gap and another not having a gap, the efficiency is only reduced by about 9% for the panels with no gap at all.

Can Solar Panels Touch Each Other?

That depends on what type they are (flexible versus rigid) and what the manufacturer recommends installing them properly.

Usually, solar panels have to have space between and around them to accommodate for possible expansion and retraction issues. Still, you should do whatever the manufacturer recommends for that particular brand of solar panels.

General Rules About Gaps When Installing Your Solar Panels

While placing as many solar panels as possible on your roof might be tempting, this is not really a good idea.

The frame and glass of each solar panel are directly affected by the temperature, which means they are continuously expanding and contracting.

Because of this, there has to be room between the panels to accommodate those expansions and contractions.

Gap from support to rail

In addition to the recommendations mentioned above, you should also provide roughly 12 to 16 inches between the first support and the end of the rail.

The panels can bounce if there is too much space between the rails. This is detrimental when there are strong winds outside, or a heavy storm occurs.

In addition, two rail pieces must have a rail splice to be stable and provide the right support.

You also have to fasten each of your panels to two rails, with the rail being long enough for all of the panels you wish to install.

gap between rafters example

On the average roof, the space for your rafters is equal to 16 inches. The standoffs have a 48-inch space between each of the posts.

This means that if you decide to install four PV modules that each measure 65 x 39 inches, the total dimension equals 160 inches.

So, if your rail is 160 inches long or more, you’ll have enough room for your panels. If it’s too long, it’s not a problem because you can cut some of it off to get the right size.

Brackets and Clamps

Also, remember that the brackets for your solar panels must be bolted with the correct flashing.

This way, the rail doesn’t move too much and therefore won’t put too much pressure on the other parts.

Make sure the clamps are the right number and size so that a good fit occurs.

The mounts must be sturdy because, let’s face it, the solar panels are resting on them.

The Ramon Z brackets are what a lot of companies recommend simply because they are well-built and strong.

Newly build houses with solar panels attached on the roof against a sunny sky Close up of new building with black solar panels. Zonnepanelen, Zonne energie, Translation: Solar panel, , Sun Energy.

Why Are the Gaps Between Solar Panels Necessary?

Solar panel frames are constantly contracting and expanding, so the panels could possibly touch each other and cause damage if they are too close together.

This is one of the reasons why you should never place your solar panels too close to one another.

In addition to the damages that could occur, your warranty is usually voided when you include no spaces between the panels. This is another reason to ensure you always have a gap between the panels.

Gaps are also important because even though the panel frame and the glass covering the cell are durable, they are simply not designed to bump into one another.

The modules can also get very hot, making sufficient gaps between them even more important.

Calculating the gap for solar panels

If you’re curious about how many solar panels will fit on your roof, you can use a few calculations to determine the right number.

Naturally, the final number will depend on many factors, including the type of brackets you use, the size of each solar panel, and even the size of the clamps you’ll be using.

Considering that most solar panels are 5.5 feet x 3.25 feet and occupy roughly 20 square feet, the typical roof – which usually covers 1,600 square feet – can theoretically accommodate 80 solar panels.

However, this only applies to roofs without chimneys and without areas that don’t get direct sunlight, which doesn’t include most roofs.

You’ll have to do some calculations to determine how many solar panels can fit on your roof. Typically, a roof can have panels on only 25% to 30% of its space.

1,600 square foot roof example – Self Build

This means that if your roof is 1,600 square feet, the number of panels you can install on the roof is 20 to 30.

You also have to look at the kilowatt-hours you’re aiming for. If you are shooting for 1,000 kWh per month and you’re planning to install 250-watt solar panels, you’ll need about 35 to 40 panels, not 20 to 30.

Modules offering 375 watts would require only 25 to 30 of them for your roof.

Today, most solar panels for homes are 250 to 375 watts. A general rule should be 1 kW for every 3.5 panels for a module that offers 285 watts.

Therefore, for panels that are 340 to 375 watts, you would only require three panels.

Company Installation

The companies that sell and install solar panels have very specific formulas that help you determine exactly how many panels you will need.

They will not walk away unless you get the number of panels you need – no more and no less.

Solar Panel Terms and Connections

If you’re a DIY enthusiast and intend to install solar panels, you’ll need to know some basic information first. Here are a few things about solar panel systems you should know before you get started:

  • Electricity is first generated in a grid tie system by one or more solar modules. Solar modules are also called PV solar panels.
  • The disconnect is a shutoff switch that separates the panels from the rest of the system. It keeps you safe should you ever need to do any repairs.
  • The solar inverter turns the direct current (DC) from the panels into alternating current (AC) for your household.
  • Power moves from the inverter to the breaker box in your home so it can be distributed to the rest of your household. When you have solar panels, you usually need a breaker box different from your current one.
  • A power meter measures the electricity needed or sold back to the utility company.

Once you understand how a solar panel system works, it’s easier to understand exactly how to set yours up.

The spacing of the modules and the other equipment necessary to set those modules up is important. Still, you have options if you need additional assistance making sure everything is spaced properly so your system works without a hitch.


While some of this information sounds complex, once you learn more about your solar power system, everything becomes easier.

Companies that make and install solar panels are there to help when you need them, and this is sometimes your smartest option over doing the work on your own.

Make sure you pay attention to their instructions because they will give you all the numbers you need to install your solar panels correctly.


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Elliot has 20+ years of experience in renewable technology, from conservation to efficient living. His passion is to help others achieve independent off-grid living.

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