Roof Maintenance



A sad site that is too common. Mastic is a product used on build up roof systems, (ASPHALT) It is a heavy-body asphalt and is very malleable when first applied. As it ages it dry's and hardens. In the photo above the "Roofer" is applying mastic all around the curb and ducting, most likely to find a hard to find leak. Here's the issue, metal expands and contracts with the daily temperatures and mastic has no chance to last. As it hardens it will begin to crack and the leak will continue. The Roofer will return and charge you again to re-coat the area until you have inches of mastic.


Mastic is designed as a patch or sealant agent on other asphalt surfaces. Even mastic that contains SBS modified bitumen compound for stronger, more flexible repairs

Roof Coating cannot last on metal surfaces, it will harden and it will eventually crack we see it all the time. The typical scenario is that the customer gets tired of being a contractors cash cow and calls another company only to become their cash cow for a while, until we get the call. By that time the nightmare is advanced in severity.


Now as asphalt roof systems begin to buckle towards the end of their natural life, and penetrations begin to leak, we can do repairs. However this is an indication that the roof life is nearing its end. We may still be able to add time to the life with repairs but it's time to start putting money away for a new roof.


Vent Ducking If the ducting of your H-vac units are leaking mastic isn't the answer as the roofer in the photo above believes. We can add a wide range of products that are designed for metal and heat that will last. Other areas we have seen mastic applied to metal surfaces are coping metals, vent pipe flashings and this may win the battle and stop the leak today, it will cost you in the overall war win it comes time to re-roof.

The sad truth is it can extremally difficult to clean mastic off metal, especially if it was applied within the past year. Older areas might bust off the surface but in other areas it may still be wet and impossible to remove. If ducting was covered with mastic removing it may now be problematic and installing the proper products can't be accomplished. This is the purpose of these blogs, hopefully we can help educate our customers before they get burned by those who should know better.


Roof Coatings is another problematic area. On new build up roof systems we can install a product called aluminum coating. It isn't a sealer it is simply a product that protects the asphalt from UV damage. If your built up roof system never had this coating applied to add life it may or may not be helpful to you, depending on the age and condition of your roof. The real problem is with rubber coatings that roofers apply as a sealer over large areas to the roof or entire roof surface depending on the desired outcome.

Many roofers will sell this coating as a new roof, while other's use it instead of mastic. On metal this product can be used to seal because it does have the flexibility even with wild temperature swings. Its not so much that the product can't seal and has to do more with the preparation of the roof surface. If the roof surface has loose dust, debris and isn't properly prepped the product will not adhere.

I have my doubts that these products adhere to asphalt and I primarily see them used on RV's and Metal Roofs. I have seen too many asphalt roofs covered with this liquid white rubber and too many time's on too many buildings I've seen it flaking away.

Armed with this information, don't just let anyone just work on your roof without first asking them what the issue is and what products they will be using. Be aware that many roofers will sell you the wrong product with confidence.

Spray Formulas Many contractors specialize in spray formulas that they claim "ADDS LIFE" to the roof system. Cedar roof spray specialists who spray Cedar wood shingles or shakes claim that the formula replenishes the oils the lost over time. These lost oils are indeed the reason why the wood shakes or shingles cup, curl or split and when this occurs its time for a new roof!


Figure A

The above image you can see that most of the shakes are split and the circled area between two shakes a spot that has detreated away down to the felt. The sun's UV rays will break down the felt and the substrate will be exposed. The cracks are forming over seams where two shingles are placed next to one another. If the crack grows this can be an area where water can infiltrate the roof and enter your building.

Image B

In this image you can see that shingles are blowing away and that the edges of shingles are detreated.

Figure C

Cupping & Curling shingles cannot bear dead load and will crack under weight. In Yakima we get snow and a roof that looks like this will suffer shakes that break. The wind is another danger as these shakes are like sails in the wind and it won't take long before you find pieces around your yard. Your roof may also begin to suffer leaks during this late stage of the roofs death.


We have torn off roofs that have had the sprays "Specially formulated", to add life back in these roof systems. When we bust the shake in half we find that the spray doesn't penetrated but a 1/16" into the surface wood. It doesn't soak through! The proper use of these copper based biocides is to kill fungi.

The Western Redcedar is the most commonly used tree used to create Cedar Shakes. This wood has extractives that make the wood dimensionally stable and resist deterioration far longer than other wood species. These extractives are toxic to fungi and insects that could colonize the wood. The suns UV's break down the wood and bake it causing the natural extractives to break down over time. In time fungi and moss can form and begin eating the wood. However a shingle roof that is out in the open and has no moss growth may be dying from the UV's. Figure C shows that the fungi thrives in the dark areas between the shakes and this is typically where we see the wood eaten by the fungi though we can see it out on the open surfaces as well.


The best time to use these copper based biocides would be long before the roof life is coming to an end. Or in areas where tree's shade and cover the roof decks with pine needles or leaves. These areas should be regularly cleaned from the organic materials and spray applied as a maintenance. This is the way this formula is designed to add life to your roof system, it is not going to add life to already detreated shingles.

When it comes to Asphalt shingles I know of many products that claim to add oils back into the base matt. Logically it doesn't compute. The asphalt shingle has a base matt made of asphalt so unless asphalt base oils are being added back to rebuild the structure of the matting I don't see how other oils will help and you can't go spraying hot tar all over some ones roof! I did speak to a company that sells and applies the spray and they show that the the shingles increase in malleability after a single application. However these shingles he admits are already malleable to begin with.


I do not trust or believe the claims of Duramax or I'd be selling and applying the products my self. It is much easier and less liability to spray a roof and walk away rather than tear a roof system off and take that risk but untimely if I don't believe the products claims I can't get behind it.


Yakima Roofing & Remodeling, LLC

With over 60 years of combined experience and knowledge not only in the roofing industry but the building industry we hope that we can pass on our knowledge and understanding of our trade to help our customers make informed decisions when it comes to their projects. If you need your roof cleaned we have several services designed to meet your needs without up selling you products that you may not need. If you do need your roof cleaned and treated for moss and fungi we can evaluate your roof and let you know if it's a worthy investment or not.


Factors to determine if your roof can be cleaned will be based on the condition of the shakes or asphalt shingles. If the shakes are cupping and curling we may not be able to walk the roof without busting shakes. However if the shakes or wood shingles are still laying flat we will estimate the extent of the cleaning.

Give us a call for a free estimate.