Can I power wash Masonite siding?

Question

I am planning on painting my house and need to clean it first. I wondered if powerwashing it might damage the Masonite siding or if that is the way to go? If I do rent a power washer, should a cleaning agent be used?

Answer 1

Hello house painter,



Masonite is a brand name of a type of siding made of pressed wood fibers. While the Masonite brand is no longer made, several other companies are manufacturing siding using a similar process. This type siding is usually referred to as hardboard siding and has always been susceptible to rapid decay if the factory primer coat fails or it is subjected to prolonged moisture. Hardboard siding has fallen out of favor with many builders and home owners because of some class action law suits, high failure rates and the introduction of newer (and in my opinion better) siding products.



More recently cement fiber siding, which is sometimes confused with hardboard siding, has become popular because it does not easily decay.



If you do have Masonite or hardboard siding it can and should be cleaned before painting it. Power washing is a quick effective way to clean a house if done correctly.





Use caution around electrical outlets and exterior lights to prevent electrocution!



Never use the high pressure jet tip or the narrow fan tips close to the siding or your self or others as the pressures are extremely dangerous. It is OK to use the high pressure tip to reach high areas on the house. Just be aware of the extreme pressures generated and use common sense in not allowing the jet to damage the house.



When installing or changing tips always point in a safe direction (at the ground) before pulling the trigger for the first time. (If the tip is not seated properly the water pressure will turn it into a projectile capable of breaking windows or causing bodily injuries)



Pay close attention to where you are spraying. The high pressure will force water under or around doors and window and into wall vents, soffit vents and attic vents.



Use liquid laundry detergent mixed at the rate of about 8 to 16 ounces per gallon of water. If mildew is present add 4 to 8 ounces of bleach. Wear protective clothing and eye protection. Apply using the siphon tip of the pressure washer or use a pump up sprayer. (laundry detergent is biodegradable ~ if rinsed down with copious amounts of water neither it nor the bleach is harmful to plants or animals)



Thoroughly soak one area / wall at the time with cleaning solution and allow it to work for three to five minutes. You can soak the next area down while you are waiting for the first area to work Just don't let it dry before rinsing.



Once the cleaning solution has had time to work on an area for a few minutes rinse it down completely with clear water until all sign of soap residue is gone. Never let the cleaning solution dry on the wall as it will redeposit the dirt that had been loosened.



Allow house to dry thoroughly before caulking and painting



Good luck,



Tony

Answer 2

Not unless you're sure it will dry before it freezes. (With a power wash, there's some question of water getting under the siding, and that takes a long time to dry.)

Answer 3

If it's still in good condition go for it. It's basically cement anyway that's why it's externally fitted, give it a wet down and a bit of normal soapy suds first, give it time to soak into the dirt etc, then hit it with power. If really stubborn a stiff brush helps Just be careful of electrical, plaster (if you've got eaves), and if you see separation between mas boards stop and move, water won't hurt it,

Answer 4

Masonite House