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How to Remove Mildew from Vinyl Siding

Vinyl siding is usually regarded as a low-maintenance choice for siding homes, but that is not entirely true. While vinyl siding almost never requires re-painting, it does need some maintenance. Every year to a year and a half you should thoroughly wash your vinyl siding.

Vinyl siding often collects dirt, mildew and mold. This is especially true in areas of your home where there is little sunlight and where shrubs and trees brush up against the siding.

Exposure to Elements

Vinyl’s two worst enemies are acid rain and UV rays. They speed up deterioration. They cause the vinyl to become brittle and porous. The rough surface absorbs and retains moisture. This encourages the walls to rot and produces mildew and mold.

It is important to spot the growth of mildew early and remove it promptly. Prolonged exposure to sunlight will cause the mildew to become baked into the vinyl siding. This will make it nearly impossible to remove. It will result in your siding becoming damaged and possibly permanently ruined.

Identify the Mildew

It appears as a grey or white powdery looking substance with black dots in it. It can not be removed by wiping with a cloth. Instead it will just smear and stain the siding. To test for mildew spray a small amount of a bleach solution onto an out of view area. Wait a few minutes.

If the substance disappears then it is mildew. If the substance remains it is probably just dirt and cobwebs. This test will also determine if it is safe to use bleach to clean your siding.

Remove the Dirt

Remove the dirt from the siding. A high pressure washer can be used but use it with caution. The powerful sprayer will force water underneath the siding causing more mildew growth in the long run. It can also leak through to the interior walls of your house. This could be very dangerous to the structure and costly to fix. To properly spray with a high pressure washer, you should always spray downwards to keep water from entering from under the siding panels.

Cleaning Solutions

A mixture of 70% water and 30% white vinegar should do the trick. If it does not remove the mildew you may try a solution of 25% bleach and 75% water. With either one, test the solution on the surface of your siding. Wait a few minutes then check for staining or bleaching. To kill all of the mildew you may need to leave the cleaning solution on the surface for up to 30 minutes before scrubbing.

Scrub with a soft brush or wash the mildew infected areas with a sponge by hand. Rinse well with a pressure washer or a garden hose. Mildew can reappear as soon as a month after washing with bleach. Monthly rinses with water will help prevent it’s return.

Wash from the bottom up, but spray water downwards. Always start at the lowest point on your siding. Work your way up the walls slowly. Rinse carefully yet thoroughly as you go along.

Bigger Problems

If your mildew problem is widespread or your home is too big for you to sufficiently clean you may want to call a professional. Leaving mildew or mold growth untreated can lead to harmful effects on your health and also the health of your pets. It can infect the lungs and respiratory system, causing serious breathing problems and possibly death.

You can help prevent mildew by installing proper ventilation ducts for steam and moisture producing appliances, like a clothes dryer. A well insulated house will have less mildew. An adequate drainage system that directs water away from your home is also a great preventative. Clean out your gutters regularly. Mildew resistant vinyl siding is available. Done together these tips should keep your siding mildew free and as beautiful as it looked when new.

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