Most Roofing Contractors might skip out on the conversation about your home's step flashing, but the reality is it's one of the most important areas you to pay attention to. As far as the roof is concerned, the most vulnerable part of your home is the transition spots (where roof and not-roof meet). Step flashing prevents leaks during these transition points and creates a watertight seal - when installed appropriately. Unfortunately, it is one of the most overlooked areas by most roofing contractors during installation and easily the biggest source of roof leaks (missing or improperly installed) when we’re called out for repairs.
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Fundamentally, Step Flashing is designed to keep water out of your home by protecting vulnerable transitions (mentioned above). All flashing is is a piece of metal bent into an L shape at a 90 degree angle. When installed correctly you’ll hardly ever see the exposed flashing from the ground (which is one reason why it’s easy to overlook).
Like all types of roof flashing, step flashing comes in a large variety of sizes and materials. There are options for it to come pre bent or unbent (where you bend it yourself, such as over a piece of plywood). Your local roofing supply company (like an ABC Supply) will usually sell it in packs of 100, where they are either 5 by 7 inches or 8 by 8 inches. The bare minimum it is to make sure they’re at least 5 ¼ inch. If they’re not at least 5 ¼ inch, the watertight seal between your roof and the wall will not form. When the flashing is over 5 ¼ inches, it’s possible for the flashing to overlap shingles just enough to create a nice watertight seal between every coarse of shingles.
Step Flashing Protects "Roof to Wall" Transitions
The majority of step flashing is made out of aluminum or galvanized steel, which helps to prevent rusting and the gauges are normally going to be somewhere between .011 and .019, although Commercially it is typically going to be around .040 gauge.
It’s crucial that step flashing be installed on all roof to wall transitions. This includes dormers, one story attached sections of the house (e.g. garage or additions) that are attached to a second level area and also installed around skylights and around and up chimneys, where it becomes overlapped by “counter” flashing.
The flashing must always be a couple inches longer than the exposure on a shingle - this guarantees a water tight system and prevents any rotting plywood if water happens to back up into the translation. Any Ice and Water shield should be installed along the side wall transposition for extra protection.
The way step flashing is installed properly is by making sure one part is over a shingle and the other part is under a shingle. When an experienced roofing contractor does the installation, the flashing cuts out any need whatsoever for caulking or silicone!
This installation pattern often confuses amateur roofers, which will then become a source of leaks in the future. In fact, when it is improperly installed it’s a very expensive fix because in order to repair step flashing, you typically have to remove shingles all around the edge and reinstall them, which requires a lot of labor and extra materials - all to make sure a single (very important) piece of metal is in the correct position!
Houses with a lot of dormers or separate roof sections are notorious for needing constant roof repairs around the area where the step flashing is. Unfortunately, this kind of situation becomes difficult to locate the exact spot of the leak, because of the sheer volume of it and the many areas that can possibly go wrong.
Even though it isn’t seen from the ground, it does get exposed sometimes. For this reason there are multiple colors of flashing available, so that if the situation calls for exposed flashing you won’t have an exposed metal look. Although, at the end of the day the majority of flashing installations are used with the default silver color.
As for non-silver colored step flashing - any color of trim is also available in flashing, except it comes at a slightly additional cost and requires additional lead time for delivery because the order is typically custom made. The reason for this is that custom step flashing is usually only used in Commercial installs that require a color matched setup.
You can learn more about common roofing components, issues and terms by following these links
Correct Step Flashing Installation is a Highly Prized Skill
Installing correctly can be tricky. You must make sure it is flush to the wall and to the roof. Any gaps in between the roof flashing that are not installed flush will allow for water to leak through. Rain water will not leak through this wrong installation, but when snow melts and freezes over and over again the ice will back up in between the step flashing cracks and either leak into the house all the way through the sheetrock or at the least, rot away the plywood.
Most Albany roofing contractors will not charge any additional cost for step flashing and will include it in the price. Be sure to make sure that roof flashing is included in your estimate. Some roofing companies will sell you a roof and then try and up charge you by saying that you need new step flashing. It should always be included and never be an additional charge unless that is how the contractor quotes the job.
Sometimes the flashing will be nailed to the wall under the house’s siding. When this occurs the roofing contractor will not be able to remove the old step flashing and will have to use the existing material. This is a common occurrence and is fine with all roofing system warranties. The existing metal will still out last the lifetime of the shingles.
Sometimes it is impossible to replace it without ruining the siding (cedar shake or metal siding). In these cases it is best to apply a roof cement sealant or installing a 1x10 pine board over a course of new step flashing with a strip of polyurethane sealant over the new seam.
If your home has a lot of roof flashing, it's important to get a true professional
As an alternative route, you can install continuous flashing. The NRCA (National Roofing Contractor Association) just recently approved continuous flashing to be used per code but has been met with much controversy. We disagree with continuous flashing against a side wall due to the many we have repaired over the years.
If you have a lot of roof flashing on your house it is of utter importance to hire a very experienced roofing contractor. There are many roofers who have been roofing for years and still do not know how to flash properly. Flashing a corner on a dormer will be the most trickiest part and is one of the most common points of failure on a roofing system.
It is important to hire a Albany roofing contractor who is knowledgeable in all aspects of a roofing system. Mistakes while installing a roof replacement can end being costly to have a roofer return and fix them. Even worse they can become even more costly and stressful when a roofing contractor is paid for a roof repair but did not find or stop the leak.
It will usually pay off in the end by paying a little more upfront for an experienced, more reputable contractor. Rather than paying 3x for the same repair.
It is also smart to only deal with a Albany roofing contractor who is certified by a reputable shingle company. Once a manufacturer puts a warranty on the roof, it is covered for labor and materials even against workmanship. This is why manufactures require the roofing company to be properly trained and knowledgeable with all roofing system components. If the roofing company does not have there own in-house warranty cover the roof, then either the manufacturer or the homeowner is responsible for all cost associated with the roof repair.