I would not even trust a professional to pressure wash my cedar shingles. Do NOT pressure wash them with anything you would find at Home Depot or that website. I strongly advise you hire a company with experience in this arena or you are going to have the biggest headache on your hands you could possibly imagine.

You need a high flow machine (5 gpms or better) to get the job done in a reasonable amount if time. You need a proper cleaner and pH balancing chemical for the sealer to last, you should probably have some type of scaffolding or lift set up. You do not want to pressure wash from a ladder. You also ned to know proper technique as not to cause water intrusion behind the shingles which could cost you thousands of dollars in future interior mold abatement.

Once again I know guys that "pressure wash" professionally and they are nowhere near qualified anough to clean and prep shingles. Please reconsider this as it is not a DIY project.

Sue,

To answer your question, a pressure washer is composed of 2 main components: an engine and a pump. Of the two, I would say the pump is the most important.

If you purchase a pressure washer with a quality engine and a quality pump you will have a quality pressure washer.

For a quality engine I recommend a Honda OHV engine (NOT OHC).

For a quality pump I highly recommend a Cat brand pump. Cat is the name of the company that makes high pressure pumps and if the pressure washer has a Cat pump you should see a sticker on the pump somewhere that says "Cat."

I think Home depot may carry pressure washers with Cat pumps - at least they used to a couple of years ago.

Not that we got that out of the way, make sure you know what you are doing. If the material to be pressure washed is soft like wood you will need to adjust the pressure, spray pattern, and incident angle and distance to the material being pressure washed so as to not damage it. This comes with experience.

Many an individual has severly damaged the surface of their deck by careless use of a pressure washer. BTW, Cedar is a very soft wood so you need to be extra careful.

Thanks. The paint store near is (the one the professionals use, they actually know what they are doing there) thinks DH will be able to easily do it. They rent them, but we are going to buy one because the house is so huge.

They basically said to use the wash first (to remove the tannic acid stains) and then to use low pressure (300-500 psi max) with a fan tip. Not to spray up under the shingles, don't stop on the shingles, etc. Pressure washing is very common where we are because lots of houses have white cedar shingles. We could hire professionals, but I trust DH more than I trust the $10 an hour ex-cons that seem to work for the majority of people around here.

Thanks for the advice.

Good Luck, let us know how it turns out.

PS: real companies use trained, high quality labor. Like with any contractor, you have to do your research. We carry $3,000,000 in aggregate liability insurance, all of our workers are covered by workman's comp insurance and are either carpenters, union painters, or former business owners. Our average bill rate is $150-$200 per hour on a job like yours.

I really should not even say this but your paint store (the ones the professionals use) are not as informed as you may think. Fan tips are not what determines pressure it is orifice size. Did they let you know what detergents and pH balancing formulas to use or were they just hyped to sell you a detergent containing bleach and soap and call it a day? Tannin bleed and extractives are neutralized by acid. Acids don't clean, for that you need a specially formulated caustic. What type of caustic cleaner is best for shingles without causing a ton of furring? How are you going to get the detergents onto the house? How do you plan on masking the glass..protecting plant life from overspray? What type of PPE wear do you own? What is the DH's plan of attack for everything over his head. Is he going to wash from a ladder? How will he prevent the unavoidable lap marks and damage to the cedar as he starts washing from that ladder?

I am more than happy to help people with DIY projects, this just isn't one of them. Your DH is going to quickly realize he is in over his head, hopefully before he breaks his neck falling off a ladder when a 3000 psi pressure spikes knocks him off the top rung of a ladder. Which by the way, happens regardless of what size or spread pattern nozzle you are using unless you use professional grade machinery equipped with flow activated unloaders.

One last thing,

Before winter arrives, you must winterize your pressure washer's pump. Home Depot carries the pump winterizer. If you do not winterize and leave water in the pump, the water will freeze and your pump will be destoyed.

Obviously, this does not apply if you store the pressure water in a heated garage or if you live where it never get below freezing.

nra4usa

Good point, NRA. Pumps have very tight tolerances and even a few drops of water remaining inside a pump that freezes and expands can wreak havoc on seals.

Yep - found out the hard way 2 years ago. Now I always use the winterizer.

plain old antifreeze works fine.

This may sound completely out of line, but I have a small electric PW. This Husky brand works well for occasional outdoor needs. We have a bazillion trees dropping crap on our concrete surfaces and this works great at cleaning it off.

Our 1300 PSI unit has 2 wands for different uses. One has a "throbbing" delivery and the other is constant and can be dialed up and down for stronger flow.

I used the stronger flow to clean paint off of a pressure-treated pine surface with good results. The same tip gouged a trail in my newish cedar fence 1/8 inch deep. I cannot even imagine trying to use a heavier machine for an enormous project like you have. The overhead work could have some serious backlash - please be very careful.

That said, good luck in doing the work or in finding a reputable contractor to do it for you.

Heavier duty machines have higher flow not higher pressure. You use the right size nozzle to bring your pressure down to 500 psi for cleaning cedar. The difference in effect can best be described by an anology.. Homeowner unit is a Water Pic (used to clean your teeth) and you have a sink full of dishes. The larger flow unit is your faucet. Both can accomplish the task but the difference will be the speed and effeciency.

PSI has absolutley nothing to do with cleaning power unless you are cleaning commercial concrete or airport landing strips.

I would just second the comment about DH falling off the ladder. That happened to mine - dislocated shoulder and broken hand. He will probably never be able to play tennis and golf like he could in the past but he was lucky compared to another person I know who also took a spill from a ladder - and shattered his femur including the hip joint and will probably never walk normally again. Be careful!!