Metal Roof Cleaning Jobs, From Mildew to Valley Debris
Soft Washing Mildew and Algae
Shaded slopes in humid weather grow mildew, algae and mold, and on a white roof the dark streaks show from the street. Soft washing means a cleaning solution and a low-pressure rinse instead of a blast of water. One coil supplier gives this mix for mildew on painted metal:
- Detergent. 1/3 cup of powdered laundry detergent.
- Bleach. 1 quart of household bleach.
- Water. 3 quarts.
Scrub lightly until the growth is gone, then rinse the roof well with plain water. Test any solution on a hidden spot first.
Rust and Runoff Stain Removal
Orange spots on a newer roof are often not the roof rusting. Loose metal particles, such as shavings left from drilling or cutting, rust on the surface and stain the paint. The fix is to remove the particles, then work the stain with a mild cleanser on a non-abrasive pad and rinse. Stubborn stains can take a diluted acid, wiped on and rinsed off within 5 minutes. If the color keeps coming back, the metal itself may be rusting, and that calls for metal roof repair, not more cleaning.
Chalky Paint and Oxidation
Chalk is the white film you can wipe off an aging painted panel. It forms when the sun breaks down the paint resin. A mild detergent wash, about 1/4 cup per gallon of water, is the standard cleaner for painted metal. It takes off the loose chalk, but it can't rebuild the paint. Most paint warranties also exclude chalking caused by pollutants, which is one more reason to keep the roof clean. Heavy chalking is a sign the panels are due for coating or repainting.
Debris in Valleys and Gutters
Palm fronds, leaves and small sticks end up in valleys and gutters, where they slow the water on its way off the roof. Routine surface maintenance, as HomeGuide describes it, covers clearing gutters and drains and cutting back limbs that touch the roof. Debris also hides damage. A cleaning visit is a good time to ask the contractor to note any loose screws, open seams or scratches they see, and to photograph them so you have a record. Small paint scratches can be touched up with a paint pen, which HomeGuide lists as part of routine surface care. Anything bigger goes to a roofer.
Why Pompano Beach homeowners call Pompano Metal Roofing
- One independent roofer per request, never a call list
- Ask for tear-off, deck repair and permit as separate lines
- No fee to homeowners for the referral or the estimate
- Your details go to that one roofer and nobody else
Metal Roof Cleaning Methods to Avoid
One coil supplier's cleaning guide lists these as off-limits on painted metal roofing:
Wire brushes and sandpaper
Abrasives that scratch into the finish.High-pressure power washers
Use a low-pressure rinse instead.Scouring powders
Another abrasive, even if it works on a sink.Paint removers and thinners
Made to dissolve paint, which is the protective layer.
Ask any cleaning contractor what pressure and what solution they plan to use before they start. Some metals need their own care. Copper, for example, is cleaned with a low-pressure rinse and a mild non-chlorinated cleaner so the patina isn't disturbed.