By Aaron Koszyk, Owner, Double A Power Washing · 7 min read
That green film working into the grooves of your composite deck right now is not going to disappear over winter. It is going to feed.
Three months of Lake Michigan humidity does things to a composite deck that a dry inland summer never would. By the time Labor Day weekend arrives at Grand Beach and New Buffalo, most lakeshore decks have a visible algae film in every groove, tannin shadows where wet furniture sat all July, and sunscreen residue baked into the surface by weeks of afternoon sun. None of that comes off with a mop.
Owners who close the cottage without addressing it are not just leaving a mess. They are sealing that biology in place under a cover for nine months. By the time Memorial Day comes around, what was a straightforward cleaning job in August has become a longer, more involved project, and sometimes the staining is permanent.
A late August deck wash takes the problem off the board before it becomes a spring restoration headache. We are Double A Power Washing, based in Mishawaka and serving the full Michiana region including the Harbor Country lakeshore from Grand Beach south through New Buffalo and Union Pier. Here is what we do, why we do it the way we do, and what you should know before you book.
Quick Answer: We soft wash composite and vinyl decks across Michiana including Grand Beach and New Buffalo, cleaning railings, stairs, and the full deck surface in a single visit. Call (574) 221-8400 for a free estimate.
Key Takeaways
- Lake Michigan humidity creates ideal conditions for algae and mold growth on composite deck surfaces all summer long.
- Leaving organic buildup over winter lets it feed on the composite surface for nine months straight, often causing permanent staining.
- Blasting composite decks with high pressure causes permanent surface damage. Low pressure soft wash with the right chemistry is the correct method.
- We clean the full structure: deck field, railings, and stairs in a single visit.
- Once a year minimum for most decks; twice a year if the deck is shaded or faces the lake and picks up heavy algae.
In This Article
What Is Actually on Your Deck After a Lakeshore Summer
Composite decking is not solid plastic. Most brands, including Trex, TimberTech, and Fiberon, are a blend of wood fiber and polymer. The wood fiber component gives the boards texture and makes them look natural, but it also gives organic material something to grip.
Algae spores land on the surface, find moisture in the grooves, and start a colony. The humidity rolling off Lake Michigan keeps those grooves damp for weeks at a time, even when the deck surface feels dry to the touch. By midsummer, a shaded deck or one facing north at Grand Beach can have a visible green film across the whole field.
A deck with full southern sun exposure may look clean at a glance but still carry a greasy biofilm that gets slippery when wet. Add tannin stains from oak leaves or wet cushions sitting in place, sunscreen and food residue from a busy season, and the occasional rust ring from a metal chair leg, and you have a layered contamination problem that requires chemistry, not just water pressure.
Why High Pressure Is the Wrong Tool for a Composite Deck
Composite decking has a manufacturing limit on the amount of pressure it can tolerate before the surface fibers lift, fray, or checker. Run a gas pressure washer at full output across a Trex board and you will see the damage immediately: the surface fuzz raises, the texture changes, and there is no reversing it.
The damaged surface becomes rougher, which means it traps more dirt and organic material going forward. You have made the problem permanently worse.
We do not use high pressure on composite decks. Our approach is a soft wash at low pressure: the chemistry does the work, not the water velocity. We apply a cleaning solution formulated for composite surfaces, let it dwell long enough to break down algae and biofilm at the cellular level, then rinse gently. The result is a clean surface without a single strand of raised fiber. The boards look the way they did when they were installed.
This is the same principle behind soft washing a house exterior or a roof. Pressure is a blunt instrument. Chemistry applied correctly and given time to work is precise.
Pro Tip: Book your lakeshore deck cleaning in late August before the fall rush. Slots fill fast along the Grand Beach and New Buffalo corridor once September arrives.
The Full Structure: Railings, Stairs, and Everything In Between
We clean the whole deck, not just the field. Railings trap algae on the horizontal top caps and in the balusters. Stairs collect debris in the corners of each tread. Post bases accumulate mold where the post meets the decking. Clean the walking surface and leave the railings green, and you have done half a job.
Our crew walks the deck before we start and notes anything that needs extra attention: heavy staining in a corner, a rust ring from metal furniture, a spot where a planter sat all summer and left a shadow of organic material. We treat those areas with targeted chemistry before the general application goes down.
For lakeshore properties with elevated decks or structures built over sand dunes, we adjust our approach to account for overspray and runoff. We are not leaving a chemical mess on the property or the vegetation below.
See the Difference
Ready for a free, no-pressure estimate?
Call or text one of our exterior cleaning specialists, or request your quote online anytime.
Call: 574-221-8400Text: 574-221-8400
Calls & texts answered Mon–Sun, 7AM–7PM
When to Book: The Late August Window
The best time to clean a lakeshore composite deck is late August through early September, before the cottage closes for the season. The algae and biofilm are at their thickest after a full summer of growth, but the deck is still in use. Your family sees the result. And the deck goes into winter clean instead of locked under a cover with biology working on it for nine months.
Miss the fall window and spring is your next best shot, right after the cover comes off and before the deck goes back into regular use. For decks on the shaded north side of a property, or those that face directly into the lake wind and collect heavy moisture, twice a year is worth it. Once before closing, once before the season opens.
We serve the full Harbor Country corridor including Grand Beach, New Buffalo, Union Pier, and Lakeside on the Michigan side, and Long Beach and Hudson Lake on the Indiana side. Summer scheduling along the lakeshore fills up fast, so booking in August puts you ahead of the fall rush.
DIY vs. Hiring a Pro
| Factor | DIY / Rental | Double A Power Washing |
|---|---|---|
| Pressure level | Rental units often run 2,500 to 3,500 PSI with no easy way to dial down | Low pressure soft wash calibrated for composite surfaces |
| Chemistry | Generic deck wash from a hardware store may not match the stain type | Targeted solutions for algae, biofilm, tannin, and organic staining on composite |
| Surface risk | Too much pressure raises and frays composite board fibers permanently | No surface damage. Boards look the way the manufacturer intended |
| Coverage | Easy to miss railings, baluster faces, stair corners, and post bases | Full structure cleaned: field, railings, stairs, and post bases |
| Timing | Most homeowners push it to spring when the damage is already deeper | We get it done in the fall window so biology does not feed all winter |
Pro Tip: If your deck faces north or sits under a tree canopy, plan on two cleanings per year. A shaded surface stays damp longer and algae moves in faster than it does on a deck that gets full sun.
What Composite Deck Cleaning Does Not Cover
We clean composite and vinyl decks. We do not clean, stain, seal, or restore wood decks of any kind. If your cottage has a pressure treated or cedar wood deck, we are not the right crew for that job, and we will tell you so rather than take the work and do it wrong.
We also cannot reverse structural staining that has been baking into composite boards for multiple seasons without any cleaning. If a deck has gone three or four years without maintenance and organic material has deeply penetrated the surface, some discoloration may be permanent.
We will tell you what to expect before we start, not after. One season of proper cleaning followed by annual maintenance is the best way to keep composite decking looking the way it is supposed to look.
Looking for more than deck cleaning? We also offer house washing, concrete cleaning, roof cleaning, and gutter cleaning throughout the New Buffalo area.
Why Choose Double A Power Washing?
Double A Power Washing has been serving Michiana since 2019. We are PWNA members, BBB A+ accredited, fully licensed and insured, and we hold a 5.0 rating on Google across more than 125 reviews. We run dedicated rigs with soft wash systems built for low pressure residential work, and we travel the full lakeshore corridor from Grand Beach and New Buffalo on the Michigan side to Long Beach and Hudson Lake on the Indiana side.
We are not a franchise and not a national brand routing calls to a subcontractor. Aaron and the crew show up, do the work, and stand behind it. When you call (574) 221-8400, you are talking to the same people who will be on your deck.
What Our Customers Say
“Excellent communications, fair price and good work.”
— Bert Bell, Google Review
Frequently Asked Questions
Does too much pressure actually damage a composite deck?
Yes, and the damage is permanent. Most composite decking has a rated pressure limit, and exceeding it raises and frays the surface fibers. Once the surface texture is damaged, there is no reversing it, and the rougher surface traps more debris going forward. That is exactly why we use a low pressure soft wash and chemistry formulated for composite surfaces instead of a pressure gun.
How often should a composite deck be cleaned in the Michiana climate?
Once a year is the minimum for most decks. Twice a year if the deck is shaded, faces the lake, or sits under tree cover that keeps it damp and promotes heavy algae growth. The Lake Michigan humidity corridor around Grand Beach and New Buffalo is particularly aggressive on composite surfaces compared to decks further inland.
Will you clean my deck railings and stairs too?
Yes. We clean the full structure: the deck field, railings, balusters, stair treads, stair stringers, and post bases. We walk the deck before we start and note any areas that need extra attention before the main application goes down.
Do you clean wood decks?
No. We clean composite and vinyl decks only. We do not stain, seal, or restore wood decks of any kind. If you have a wood deck, we will tell you upfront that we are not the right crew for that work.
How do I get a price for deck cleaning near Grand Beach or New Buffalo?
Call us at (574) 221-8400 or visit doubleapowerwashing.com and request a free estimate. Deck pricing is based on square footage and the condition of the surface. Most estimates can be turned around quickly, and we can often fit lakeshore jobs into the schedule within a week or two during the late summer window.
That algae film on your Grand Beach or New Buffalo deck is not waiting for spring. Every week it sits under a closed cover is another week of biology working deeper into the composite surface. A fall cleaning now costs less in time and money than a spring restoration later.
Call us at (574) 221-8400 or get a free estimate at doubleapowerwashing.com. We serve the full Michiana region including the entire Harbor Country lakeshore corridor, and we are booking late August and September slots now.
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