To protect your cleaned vinyl siding, you can use a specialized vinyl siding wax or polymer sealant. These products create a protective layer on the surface, helping to repel dirt, mold, and UV rays. Look for brands specifically designed for vinyl, as they will adhere better and offer longer-lasting protection.
Typically, the cost for a good quality vinyl siding wax ranges from $15 to $30 per gallon, depending on the brand and where you purchase it. Some popular options include products from 303, Meguiar's, or Rejuvenate. Make sure to read the instructions for application, as some may require a spray application while others can be applied with a cloth or sponge.
Before applying, ensure your siding is completely dry and clean. You might want to consider reapplying the wax every 6 to 12 months for optimal protection.
As a next step, check local home improvement stores or online retailers for available products and prices. If you prefer, you can also get 2–3 local quotes on Handyman.com for professional cleaning and waxing services.
— Assisted answer