Will the Moss or Algae Come Back After Treatment?
If you’ve ever dealt with moss or algae on your roof or siding in the Pacific Northwest, you know it’s not just a one-time problem — it’s a cycle. So naturally, one of the most common questions we get at Johnny Tsunami Exterior Cleaning is:
“How long will the treatment last? And will the moss come back?”
The short answer? Eventually, yes. But the long answer is more important — and that’s where smart maintenance and timing come into play.
Why Moss and Algae Keep Coming Back in the PNW
The PNW has the perfect recipe for moss and algae:
- Constant moisture and rain
- Lots of shade from evergreens
- Mild temperatures that don’t kill spores
- Organic debris (like pine needles) piling up on roofs
Once moss or algae starts growing, it feeds off of this environment and spreads — especially on north-facing roofs or those shaded by trees.
What Our Treatment Does
At Johnny Tsunami, we use a biodegradable soft wash treatment that:
- Kills moss and algae at the root
- Loosens buildup safely from the surface
- Soaks into porous roofing to neutralize spores
- Doesn’t damage shingles, paint, or landscaping
We apply this with a low-pressure system designed for long-term results. You’ll see moss turning yellow or brown within a few days — that’s it dying off and detaching naturally.
How Long Will It Stay Gone?
Most of our roof and siding cleanings last 12–18 months, depending on:
- How much tree cover you have
- How well your roof drains water
- What time of year you get cleaned
Here’s the key: cleaning at the right time and maintaining your home in between cleanings makes all the difference.
Maintenance = Moss Prevention
Want to avoid repeat growth? Here’s what we recommend:
1. Annual or Biannual Roof Treatment
Moss starts growing again the moment conditions allow it. A yearly treatment keeps growth suppressed before it gets out of hand.
2. Gutter Maintenance
Clogged gutters cause overflow and excess moisture — which moss loves. Cleaning your gutters 2x/year reduces roof saturation and slows regrowth.
3. Trimming Trees
If branches are shading your roof or siding, moss will return faster. A little sun exposure makes a huge difference.
4. Join Our MX Plan
Our Maintenance Plan includes automatic scheduling, preventative treatments, and member discounts — so you’re always one step ahead without lifting a finger.
The Timing Trick: Clean in Summer or Winter
If you clean your roof in the summer, moss dies and stays gone all winter.
If you clean in the winter, you catch early growth before spring rain fuels it.
Either way, it’s better than waiting until it’s green and thick again.
Final Word: Yes, It Can Come Back — But It Doesn’t Have To
Moss and algae are aggressive here. But they’re also manageable — if you stay proactive.
Let Johnny Tsunami help you get ahead of the cycle. Book your roof treatment or maintenance plan today and enjoy a clean roof with no surprises next season.
📞 Call us or request your estimate now
