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Cleaning roofs, as we mentioned in earlier post, can be done in dozens of ways using many different cleaners and tools. As roof cleaning contractors, we want to use the method that keeps our material and labor costs as low as possible while producing results that our customers will appreciate and recommend to others. We also want to be safe, so minimizing the potential for injury is a very important consideration.

We have introduced the ideas of water brooms, surface cleaners, and using a pressure washer. We have also talked about ‘no pressure’ washing with strong cleaners that do all the work. Of all these methods, the safest, lowest cost method is to apply strong cleaners to a roof with a bleach-rated pump. This can be accomplished either from the ground or up on the roof (if you have the proper safety equipment).

While we cannot point to any single method as “the only way”, we know that the most successful contractors cleaning roofs today use strong cleaners and no pressure. The primary ingredient of that strong cleaner is sodium hypochlorite, or bleach. You must have the proper equipment for this technique. Here are some suggestions.

First, you have to arrive at the job ready to work. You can buy or build roof cleaning rigs that fit into the bed of a standard pickup truck, or you can use a trailer rig for this. Using a trailer frees your truck up for other duties, so that is the preferred rig.

Next, you will need a few extension ladders of differing lengths. On the job, you will always grab for the shortest ladder that will do the trick, because of the weight and clumsiness of carrying longer ladders.

You will need one or two detergent tanks. It is ideal if the tank intended for bleach is light-proof (either molded in an opaque color or painted) to delay the break-down of the bleach from sunlight.detergent tanks used for roof cleaning

The ideal size of your primary tank is 100-125 gallons. You are limited by DOT to carrying 1000 pounds or less of any strong caustic like bleach, and that usually comes down to a little under 125 gallons.

If you have one tank, you will premix your final cleaner (bleach and soap) in that one tank. If you have two tanks, the second one can be as small as 30 gallons and is used for the soap you will add to the bleach.

You will use about 60 gallons of this mix to clean a typical roof, so your 125-gallon tank should get you through two jobs before you have to go and refill.

Chemical transfer pump for roof cleaningNow to the more expensive parts. You need to purchase a chemical transfer pump that will handle bleach. Some pump manufacturers offer Santoprene-fitted electric pumps, which can hold up well against bleach for a fair amount of time. If you use an electric pump like this, you can use a 12-VDC source for power. This may be a battery or you may even tap your vehicle as a power source. Some pumps are available in 120 VAC configurations, but they require a generator for power and there is no appreciable advantage to using them. Pump failures have to be expected with electric pumps, primarily due to the corrosive nature of bleach. It is often wise to have a second pump standing by in case you need it.

Alternative transfer pumps are gas-driven and built entirely of stainless steel and poly, which are impervious to bleach.

The pump you choose should deliver between 4-8 GPM, or you will waste a lot of time. The pump is permanently mounted to your rig, so you need a long hose to deliver the cleaner to the roof surface. There are several choices in hose material, some being “bleach-rated” and some being just plain inexpensive enough to throw away when it starts being affected by the bleach. Bleach-rated hose sells for about $2/foot, while clear braided poly hose goes for as little as $0.50/ used for roof cleaning

The diameter of the hose can make a huge difference in the volume and throw-distance you achieve with your pump. Contractors use hose that is sized between 3/8” and ¾” and anywhere in between. There is little cost difference between various sizes, and it is suggested that ½” or 5/8” might be just right.

Length of the hose is affected by your target market, but most contractors look at either 200’ or 300’ as the perfect length. This amount should allow you to reach all sides of a typical dwelling in your area. Keep in mind that many upscale neighborhoods featured very detailed roofs with difficult areas to reach. It is always better to have too much hose than not enough. Avoid splicing this hose as much as possible, as every splice is a possible future leak. Leaks destroy your pump’s ability to deliver, and may result in property damage.

If you use poly-braid hose, it will begin to discolor and turn stiff within a few months. You will likely replace this hose annually. If you want to get the most out of your hose, we suggest using a hose reel. This can be any hose reel, but if it is made with stainless parts (at least the plumbing) then you will get longer life from both the reel and the hose. If you elect to work without a reel, you will be coiling up the hose each day after work. Eventually as the hose stiffens this task gets harder and harder.

You want the pattern of the chemical spray to stay as tight as possible. A wide ‘splashy’ pattern leads to chemicals reaching spots you didn’t intend to hit. Ideally, a small pattern around a foot in diameter is ideal. You may have to experiment a little to achieve the pattern you are looking for, but most people are successful using 0-degree shooter tips such as a 0040, 0050, or 0060.
equipments used for roof cleaning
Remember that plastic and stainless are not damaged by bleach, so make sure that your tip and gun are constructed of these materials. Some contractors build a gun using a ball valve, plastic pipe, and stainless nozzles. Variations abound, with most in favor of a bend downward at the end of the pipe. In stainless, this ‘bend’ is literally a bend in the tubing. In a plastic wand, a 45º fitting is added. Some dealers offer bleach-rated wands and guns already assembled for you.

Many contractors use a “multi-tip” tool that holds three or four assorted nozzles. This allows you to adjust your spray for conditions without having to look around for the last place you had that certain nozzle. They are all right at the end of your gun.

Among the miscellaneous items you will need to round out your equipment include a water hose and mixing buckets (if any part of your cleaning mix is in powder form). You may need rags, tarps to protect areas, light paper drop cloths for landscape plants, and other small items. Optional (but really nice to have) are things like ladder stand-offs (that allow you to place a ladder and climb it without hitting gutters) and a tool one manufacturer makes to continuously feed water to the gutters to keep the bleach from accumulating.water hose - roof cleaning

You should have whatever you need for contingency plans – in case you pump or hose fails or you get strong cleaner on an unintended surface.

Most importantly, you must invest in safety-related items. These include eye protection (like goggles or a face shield) and skin protection (rubber gloves, a face shield, etc.). You may want a rubber apron to wear when you are transferring chemicals, too. If you climb on to the roof to clean it you want that safety harness and possibly a portable anchor system that allows you free movement on the roof without the danger of an injurious or fatal fall. You also want Korkers or Cougar Paws for your feet to give you unbelievable traction on the slipper surface. Next, consider a respirator. Most strong chemicals will take your breath away, which is really scary up on a roof. Finally, you likely will want a waterproof pocket for carrying your cell phone, which can be your lifeline if you run into trouble.