A solar array turns a simple roof cleaning into a two-trade job.
The shingles under and immediately around the modules are the dampest, shadiest part of the roof, which is exactly where algae and moss establish first. They are also the part nobody can reach without either specialised technique or a licensed electrician detaching the array.
On top of that, a photovoltaic system carries live DC voltage in daylight regardless of whether the system is switched off. Both the module manufacturer and the installer typically have warranty terms about who may work on or around the array.
Here is what is actually possible, what it costs, and how to keep every warranty intact.
We started getting these calls about four years ago, and they have not stopped. Connecticut put a lot of solar on roofs in the 2010s, and those arrays are now old enough that the shingles underneath them have a growth problem. Most of the homeowners who call us have already been told by someone else that the job cannot be done. That is only half true.
Can a Roof With Solar Panels Be Cleaned?
Yes, in part. The exposed shingle around and below the array can be soft washed normally with the equipment protected. The perimeter and the shingle at the module edges can be partly treated with careful low-pressure application. The area directly beneath the modules cannot be fully cleaned without a licensed contractor detaching the array.
Three tiers, plainly:
Around and below the array: yes. Standard soft wash, with all electrical components protected and rinsed.
The perimeter and the edges under the module frames: partly. Careful low-pressure chemical application reaches some of this, and treated runoff carries under the modules to a degree.
Directly beneath the modules, fully: no. Not without detaching the array. Anyone who tells you otherwise is either overselling or planning to spray equipment they should not be spraying.
The honest framing for most Connecticut homes: treating what is reachable plus a prevention strategy is the right answer. Full detachment is a decision driven by roof age and array age, not by algae
Why Algae and Moss Concentrate Around Solar Arrays
Once you see the mechanism, the pattern on your own roof will make sense.
Permanent shade. The shingle beneath a module never gets the UV and heat that normally suppress growth on the rest of the roof.
Trapped debris. Leaves, pine needles and seed pods collect along the lower module edge and behind the racking. In Newington’s oak and maple neighbourhoods this builds up fast, and once it is behind the racking it stays there.
Concentrated water lines. Modules shed water in tight bands along their lower edges instead of spreading it across the roof. Those bands stay damp.
Restricted airflow. Surfaces under the array stay wet for far longer after rain than the open roof does.
Wildlife. Birds and squirrels nest under arrays constantly around here. That adds organic debris and blocks drainage further.
The net result is that the roof under an array often ages differently from the rest of the roof. That is the whole reason this problem is worth taking seriously.
Why This Is Not a Job for a Standard Roof Cleaning Crew
The system is live in daylight
PV modules produce DC voltage whenever light hits them. Shutting the system off at the inverter or the rapid shutdown device does not de-energise the modules themselves or the DC conductors running between them.
Water plus energised electrical equipment is exactly the combination it sounds like.
Nothing should ever be sprayed directly at:
- Junction boxes on the rear of modules
- MC4 connectors
- Conduit runs and roof penetrations
- Microinverters or optimisers mounted under modules
- Rapid shutdown devices and combiner boxes
- The inverter and disconnect on the wall below
The modules themselves are sensitive
Module surfaces carry anti-reflective coatings. Frames are anodised aluminium. Edge seals and backsheets were never designed for chemical exposure.
A solution that is entirely appropriate for asphalt shingles is not necessarily appropriate for module glass, coatings and seals. Overspray has to be controlled and rinsed, not shrugged off.
And nobody steps on, leans on, or rests equipment on a module. Modules are structural in one direction only, and micro-cracking from a point load is invisible until output drops months later.
The roof penetrations are the vulnerable point
Every mount is a hole in your roof with a flashing over it. Directing water at those flashings, particularly up-slope, is how you find out whether they were installed well. That is not a test you want run on a Tuesday afternoon.
In Connecticut, solar work is licensed work
Detaching and reinstalling a PV array is electrical work. Connecticut licenses photovoltaic work specifically, alongside the general electrical licence classes, and residential contracting also falls under CT DCP HIC registration. Verify anyone at eLicense.ct.gov, and confirm current PV licence class designations with the Department of Consumer Protection.
Detach-and-reset work will generally require permits through the Town of Newington Building Department, and re-energising may involve notifying Eversource or your utility depending on the scope.
To be clear about our own role: Mr-Suds does not perform electrical work or detach-and-reset. That is a licensed PV contractor’s job. We clean what can be safely cleaned and we say so in writing.
Check Your Solar Agreement Before Anyone Touches the Roof
Five minutes of reading your solar contract can save five figures. Do it before you book anyone.
Who actually owns the array? Owned outright, financed, leased, or under a power purchase agreement? If it is leased or under a PPA, you generally do not have the right to authorise a third party to work on or detach it. Unauthorised work is one of the most common ways homeowners breach a solar contract without realising it.
Is there an operations and maintenance agreement? Many Connecticut installations, particularly those financed through Connecticut Green Bank programmes or the state’s residential solar framework, come with O&M terms specifying who may service the system. Programme names and terms in Connecticut have changed repeatedly, so check your own paperwork rather than what you remember being told at signing.
What does the installer’s workmanship warranty say about third-party access? Roof penetrations are usually covered by the installer, not the module manufacturer. If someone else touches the mounts, that coverage is often the first thing to go.
What does the module manufacturer’s warranty exclude? Typically chemical exposure, improper cleaning, physical damage and unauthorised modification.
Then call your installer and ask two questions:
- “Do you offer detach and reset?”
- “If a cleaning contractor works around the array without touching it, does that affect any of my coverage?”
Get both answers in writing. An email reply is enough. This is the same principle we cover in keeping your roof warranty documentation in order, and it applies twice over when there is a second manufacturer involved.
Your Three Real Options
Option 1: Clean around and treat what’s reachable
This is where most homeowners land, and for good reason.
The work: soft wash the exposed roof, careful low-pressure treatment at the array perimeter, full protection and rinse-down of all equipment, and debris cleared from the lower module edge and racking channels.
Best when: the roof is under roughly twelve years old, growth is moderate, and the array is functioning normally.
Honest limitation: the shingle directly beneath the modules will not be fully cleaned. We put that sentence in the written scope every time, because it is much better said at the quote than discovered afterward.
Option 2: Detach and reset
A licensed PV contractor removes the modules. The roof is cleaned or repaired in full. The array is reinstalled and recommissioned.
Best when: the roof is approaching replacement anyway, there is suspected damage or leakage at the penetrations, or a warranty or insurance issue requires full access.
Cost reality: detach-and-reset is typically priced per module, and for a typical residential array the total commonly runs into the low-to-mid four figures before any cleaning or roofing work. Get current local quotes rather than relying on a number from an article, including this one.
The piece of advice that matters most here: if your roof is within a few years of replacement, do not pay for detach-and-reset twice. Combine the roof replacement and the array reset into a single project. For anyone in that position, that one decision is worth more than everything else on this page.
Option 3: Do nothing, manage the growth
A legitimate choice in some situations. Newer roof, light growth, or an array under an active lease that restricts access.
If this is you, put everything into suppression instead:
- Clear debris from the racking and module edges annually
- Trim overhanging limbs back
- Keep the gutters clear
- Fit zinc or copper strips at the ridge above the array
That last one deserves emphasis. Ridge-mounted zinc releases metal ions with every rainfall, and that runoff carries down across and under the array. It is genuinely the best tool available for the area you cannot reach. If you take one thing from this article and you have a leased system, take that.
We will tell you exactly what we can treat on your array’s roof and what we cannot, in writing, before you book. Call Roman at (860) 263-9031.
If You Haven’t Installed Solar Yet, Read This First
Clean the roof before the array goes on.
Once modules are mounted, the shingle beneath them is effectively inaccessible for the entire life of the system. Have the roof soft washed and, ideally, have zinc or copper strips fitted at the ridge before installation day.
It costs a few hundred dollars. It is the only cheap moment you will ever get on that part of your roof.
And the companion point, which your solar salesperson may not raise: if the roof is more than about twelve to fifteen years old, replace it before installing solar. Otherwise you are buying a detach-and-reset within a few years of installation, at full price, on top of a new roof.
We have had this conversation on driveways in Newington and Rocky Hill with homeowners who had already signed a solar contract. It is a much better conversation to have a month earlier.
What to Do Right Now, Step by Step
- Locate your solar contract, warranty documents and O&M agreement.
- Determine ownership: owned, financed, leased or PPA.
- Photograph the array edges, the shingle visible around and beneath it, and the racking channels.
- Check your monitoring app for output trends. A drop can indicate soiling, shading or a module fault, and it is worth knowing before anyone visits.
- Contact your solar installer with the two written questions above.
- Book a cleaning contractor who will state in writing what will and will not be treated, how equipment will be protected, and that no spray will be directed at electrical components.
- Confirm credentials: HIC registration at eLicense.ct.gov, certificate of insurance, and pesticide business registration, since commercial biocide application in Connecticut falls under CT DEEP’s Pesticide Management Program (CGS §22a-61(a) and §22a-66c(a)).
- If detach-and-reset is on the table, have the electrical work quoted separately by a licensed PV contractor and sequence it with any roofing work.
- Clear debris from the racking and lower module edges at least annually. This alone slows growth noticeably, and it is the one maintenance task you can schedule with your annual gutter cleaning.
FAQs
Can you clean a roof with solar panels on it? Around and near the array, yes. Fully beneath the modules, only with detachment by a licensed PV contractor.
Will roof cleaning chemicals damage solar panels? They can if overspray is uncontrolled. A correct job protects the equipment, controls overspray and rinses thoroughly. Nothing should be sprayed directly at modules or electrical components.
Do panels have to be removed to clean the roof? Only for full access underneath. That is usually justified when the roof is near replacement, when there is suspected leakage at the penetrations, or when a warranty claim requires it.
How much does solar panel removal and reinstallation cost? It is typically priced per module and commonly reaches the low-to-mid four figures for a residential array. Get current local quotes before budgeting.
Does moss grow under solar panels? Yes, readily. Permanent shade, trapped debris and restricted airflow make it close to ideal conditions.
Should I clean my roof before installing solar? Yes. And if the roof is fifteen or more years old, seriously consider replacing it first.
Will cleaning around my array void the solar warranty? It depends on your installer’s and the manufacturer’s terms. Ask both, in writing, before you book anyone.
Can I clean the solar panels themselves at the same time? That is a different job with a different method, generally deionised water and a soft brush with no chemicals. Ask your installer or a panel cleaning specialist. We do not treat module surfaces as part of a roof wash.
Get a Straight Assessment of What’s Cleanable
Get a Written Scope Before You Book
We will come out, look at the array, look at the shingle around it, and give you a written scope that says exactly what gets treated, what does not, and how your equipment will be protected. If the answer is that you need your installer involved first, we will tell you that too.
See our roof soft washing service, what soft washing actually is, and real before and after results.
Get a Free Quote or call (860) 263-9031
Veteran owned. Licensed, bonded and insured. HIC registered. Soft wash only. Owner-supervised on every job. Serving Newington, Hartford, Wethersfield, Rocky Hill, Glastonbury, Farmington, Simsbury and Central Connecticut.