Thursday, November 24, 2022
HomeEditor PicksHow To Install Roof Flashing Against Siding

How To Install Roof Flashing Against Siding

What Tools Are Needed To Install Flashing Under Siding

How to properly flash roof obstructions

Flashing can be installed alongside engineered wood lap siding using the following tools and materials:

  • Metal flashing pieces or coil stock
  • Flashing tape
  • A hand seamer

Some pieces of flashing, like Z-flashing, can be purchased off the shelf in certain measurements,

Ojeda adds. He notes that while LP SmartSide siding installation instructions require Z-flashing to have a 4-inch upper leg, stock flashing may not always meet that requirement. If this is the case, supplement the stock Z-flashing with flashing tape to create the 4-inch upper leg.

Installing Corners And Field Joints

There are two main methods used for outside corners. The choice depends primarily on the desired appearance but also the experience and skill of the installer. Mitered corners offer a professional looking finish. They are most commonly used with horizontally applied siding applications such as bevel. Mitered corners require good carpentry skills. They must fit tightly for the full depth of the miter.

Corner boards are a popular and easier alternative to mitered corners. Thickness of the corner board will depend on the thickness of the siding. The most common are 3/4 inch or 1-1/4 inches thick. Width is a matter of taste and proper proportion. Corner boards are applied to the sheathing with siding fitting tightly against the narrow edge of the boards, allowing for expansion and an adequate caulking bead. The corner boards and the ends of the siding are nailed to the corner studs which anchors the wood for a maintenance-free joint. Designing roofs with an eaves overhang to protect corners from weathering also helps ensure trouble-free joints. Always apply primer or stain end cuts. With corner boards, there is the choice of applying them next to the siding or over top of the siding as shown here.

As in the above illustration, at inside corners, siding is frequently butted against a 2 x 2 trim strip. It can also be butted against adjoining walls with a trim strip used to cover the joint.

Alternate Flashing And Shingles

Lay a shingle over the step flashing starting at the roof edge. Fasten that shingle with two galvanized nails at the top, then cover the top of it with another piece of step flashing, nailed to the wall. Work up the roof in steps, covering each end of flashing with a shingle and each end of a shingle with flashing, so there are no open seams. Alternate flashing and shingles to the roof peak, advises Fine Homebuilding.

You May Like: Average Shingle Roof Cost

Install Flashing Under Siding To Stop Leaks

Q-Last year I added a room to the back of our house and ever since have had trouble with roof leaks from where the flat roof on the new extension meets the existing wall of the house. I installed metal flashing that covers the bottom row of siding and then laps down onto the surface of the roof. This flashing is made of copper, and all nailheads are covered with roof cement. The roof still leaks after snow has accumulated or after a heavy rain. Any suggestions?

A-The flashing was not properly installed. It should go under the bottom two rows of siding, then fold it out over the roof for at least 8 to 10 inches. In other words, you will have to rip off the bottom rows of siding to install the flashing, then replace the siding. In addition, it is best to cover all of the exposed flashing with a thick layer of asphalt roof cement, carrying this well past all the exposed edges.

Q-The concrete foundation of our home has cracks that allow water to seep in after a heavy rain. One contractor recommended injecting a special clay into the ground on the outside, then patching the cracks on the inside. Another suggested putting mastic and special panels on the outside and patching on the inside. And a third said we should dig a trench around the inside walls and put in a drain with a sump pump. Which of the three techniques do you favor?

Q-My hardwood dining-room table has marks left by a felt-tip marking pen. What I can do to remove these stains?


Moisture Entering House Wall Improper Roof And Wall Flashing

âHow to Perform Roof Inspectionsâ? Course

The picture below is a before picture of a recent rot repair job we did. From the driveway this discolored wall looks like a mildew problem that could easily be cured by cleaning with bleach.

Well thats what I thought too until I was up on a ladder and noticed a small hole and missing and improperly installed roof and wall flashing.

View from above shows a hole on the top section of the fascia and clapboard, hidden from ground view.

Close up of hole. Water has been getting behind the siding. When I pushed on the siding the entire wall flexed which indicated improper roof and side wall flashing not a good sign.

My nail punch pushed easily through the clapboards and plywood sheathing. Another bad sign.

This house is 20 years old the gutter contractor installed this rain divert-er or kick out divert-er which probably kept the majority of water out of this wall.

This kick out divert-er certainly helped but was not tall enough and was not installed under the step flashing above it. This house was also missing one final piece of flashing which was the main reason this wall flashing system failed to keep water from entering the building envelope.

If you look closely where the clapboards angle turns and becomes a vertical butt joint this area should have had flashing installed under it and overlapping the clapboard below. Instead if curls out and ends at the but joint.

Recommended Reading: Hydrostop Premium Coat System

Nail The Flashing To The Wall

Slice along the bend line about 4 inches into the first piece of flashing at the bottom of the roof with tin snips. Fold the roof side of the flashing down over the facing board along the roof line. Bend the vertical edge at about a 45-degree angle to make a tab to “kick out” water, away from the wall and over the bottom of the roof. Nail the flashing to the wall with two galvanized roofing nails and a hammer, instructs Renovation Headquarters.

How To Install Step Flashing Under Siding

Related Articles

Keep water out of your home and running down the roof where it belongs with appropriate use of step flashing. Step flashing is used where a roof meets a wall, to cover the junction of those elements, preventing leaks, says Roof Key. Flashing is a strip of metal, usually aluminum, about 8 inches long, and bent at 90 degrees with each side at least 5 inches wide. On a wall to be covered with wood, cement board, vinyl or metal siding, the step flashing, and associated roofing, must be installed first, so the siding can cover the top of the step flashing on the wall.

Also Check: Rv Vinyl Roof Repair

Common Roof Flashing Installation Mistakes

  • Flashings slope. Poor flashing installation may result in what is called flashing slope. This happens when the flashing gets bent, resulting in a slope that typically goes towards the wall. As such, make sure not to cause any bends in the material. Make sure that the roof flashing is facing away from the wall as well, so as to keep the wall from accumulating too much moisture.
  • Caulk in the gap between siding and roof flashing. As mentioned, it is important to leave at least a of an inch gap between the flashing and the siding. Do not fill the gap with caulk, this would defeat the purpose of the gap. The gap between each siding acts as a window to let the moisture accumulating in the walls escape.
  • Closing the gap. Another common mistake folkseven professionalsmake is to close the gap between each siding. As said, the gap serves as a window to let the accumulated moisture in the wall escape. That way, it prevents the wall from becoming a breeding ground for mold and mildew.

Signs Of Roof Flashing Failure

How to install shingle roofing, using step flashing against a wall

The clearest indication that flashing is underperforming is by water leaking into the house. Of course, it is desirable for any homeowner to catch the issue before leaking occurs in this case, here are some specific outside signs for the homeowner to look for that may imply flashing that is not protecting your home:

  • The shingles are curling, broken, damaged, have lost granulation, or are missing .
  • The asphalt or wood shingles are moldy, decaying, or splitting.
  • Patches, cracks, or tears in the roof.
  • The flashing itself tears or buckles around the roof features. When this happens, chimneys, specifically, will have missing, damaged, or stained brick.
  • The sealant, if present, is crumbling or missing. Or nails, if used in place of sealant, are missing. Both circumstances will make the flashing loose.
  • The fascia is decaying or stained.
  • The gutters are rusting, sagging, bending, or have leaky seams. Gutters may even become clogged.

The homeowner can inspect the inside of the house as well.

  • In the case that the roof has patches, cracks, or tears, the homeowner may also find water spots, mold, damaged rafters, or leaks in the attic.
  • Moisture marks and/or brown, yellow, or gray stains are present along the walls or ceiling.
  • An increase in energy cost may denote the roof ventilation is compromised.

Don’t Miss: How Much Roof Overhang On Shed

Best Way To Retro Flash Roof Against Wood Siding Wall

I had a contractor build a shed roof on the back side of my carport that extended over and attached to the house. The part of the house that it is attached to is wood lap siding. When he shingled the new roof he just used roofing caulk where the shingles meet the wall no flashing of any kind. Im afraid that with time that rain is going to find its way between the roof and the wall and cause wood rot. What is the best way to ensure no problems with this situation short of tearing the siding and/or shingles off and step flashing behind the siding like you would do if you were building a new house?

The only way is to cut a groove in the siding and flash the roof wall intersection. Or pull the nails out of the closest layer of siding and slip the flashing up under it, and hopefully under the moisture barrier.

imo and that is all it is. My opinion.

The only way is to cut a groove in the siding and flash the roof wall intersection. Or pull the nails out of the closest layer of siding and slip the flashing up under it, and hopefully under the moisture barrier.

imo and that is all it is. My opinion.

The shed roof does have some slope and the lap siding on the wall is 4″. Again, color me uneducated about these kinds of things , but Im having a difficult time of seeing how to retro flash where the roof meets the wall in my application. Do you have any pictures of something similar?

let us know how it goes.

What Is A Roof Flashing And Why Is It Important

While roofs are purposely constructed to allow rainwater run-off, they can often have several vertical features or protrusions, such as chimneys, parapet walls, half walls, dormers, skylights, vent pipes, and the like, where water can pool up and/or drip into the crevices between. The areas can eventually become damaged and allow water seepage and leaks into the house. To prevent this, professional roofers apply roof flashing to divert rainwater down the sides of the vertical surfaces, keeping the water from stagnating.

Roof flashing is typically a thin metal material fabricated from rust-resistant metal, such as G-90 galvanized steel, a frequently used flashing material, copper, or aluminum. Depending on the company, flashing may even be available in lead or zinc alloy.

Steel, copper, and aluminum are particularly used because of how malleable these metals are, rendering them easier to shape. However, the homeowner should note the different characteristics of each metal:

Flashing closes the joints between the roof and the roof features in order to protect the house from erosion and leaking. A lack of flashing or poor flashing installation can also lead to wood rot, potential shingle damage, or deck collapse, among other issues.

Flashing comes in various shapes and is used for different areas on the roof . For this reason, different flashing types will be installed in dissimilar ways, and the cost of flashing will vary.

Read Also: Skylight On Metal Roof

Flashing Under Aluminum Siding

Im taking estimates for replacing my roof. Three contractors have not given me a solid answer as to how they will deal with the flashing where the roof meets aluminum sided dormers or aluminum sided walls. The roof has three levels. One suggestion was to make a cut in the aluminum siding parallel to the roof line, replace the flashing and then insert an aluminum covered board over where the cuts were made. Doesnt seem right to me.

I couldnt give a solid answer either. Mentally, Ill have a Plan A that circumstances can cause me to switch to Plan B, then Plan C and next thing I know, the reality of the specific situation might have me on Plan H by time I get it flashed.

The method we use is to score the siding deep with a fresh straight blade 1 1/2 inches up from the roof deck, carefully remove the waste and J channel and install 3in tall step flashing under the siding. Then shingle normally. We use a urethane base caulk to glue the J back in place, supporting it with shingle scrap until cure. Good luck, its a PITA whatever you do.

We just remove the aluminum siding, ice and water, re-flash and re-install the old siding. It has never proven too difficult.

Is your J channel sitting on the roof deck?.,.If the step flashing was not nailed to the wall then a nail bar can be used to remove the old and install the new.

And yes.,if you go in like a bulldozer with a tear off spade then yeah you could destroy the siding and charge the customer.

We Will Now Go On To See How To Install Kick

Replacing Roof Flashing at a SideWall
  • Place a kick-out flashing at the base of the roof and flush against the wall. Remove the flashing and apply some roofing cement to fix the flashing into place.

  • Place the first piece of step flashing over the end of the tarter strip. Ensure that the step flashing will lead the water directly into the kick-out flashing.

  • Use roofing cement and nails to secure the step flashing to the deck. Make sure that the nails are high enough so that they will be covered by the next course of shingles.

  • Having fixed the first step flashing in place, apply sealant to the base of the flashing. Place a shingle so that it covers the nail of the first step flashing and nail the shingle in place.

  • Finish placing and fixing all the shingles.

  • Place the next piece of flashing so that it overlaps the previous flashing by at least three inches.

  • Apply sealant where the two flashings overlap and nail the new shingle in place.

  • Repeat the process alternating between shingles and pieces of flashings till you reach of the top of the roof.

Roof splashing, done properly will keep the walls of our homes safe from soaking up water during rains. Further rains will lead to water seepage into our homes and rotting of roof timber. Roof leakages and deck crashing are some of the consequences you will have to put up with if your roof flashing is wrongly done or deteriorates. We hope this article on how to install roof flashing against a wall will help you in roof flashing the roof of your home.

Don’t Miss: How Much Do New Shingles Cost

Retrofitting Step Flashing Without Removing The Siding

We needed to cut back the siding to create a new air gap but we knew that 3/4 was not enough to slip flashing under without damaging the siding. Our solution was to cut a 6-1/4 of the siding away, creating a space to allow the installation of step flashing. We would then cover this space with a removable trim board.

We chose 6-1/4 because it allowed us to install a 1×6 without having to cut the trim board and it also provided a 3/4 air space over the roofing.

We measured up off the roofing 6-1/4 on both the top and bottom of the roof, snapped lines and then removed any siding nails that were on the chalk line.

We then set our circular saw to cut through the siding and not the plywood behind. We removed the cut clapboards next and installed step flashing.

Once the step flashing was installed we primed all of the cut clapboard ends and installed a drip cap flashing under the clapboards.

The flashing covers and protects the joint on top of the trim board. The trim board was then installed under and tight up to the drip flashing. We made sure to keep out fasteners high on the trim board and away from the step flashing. When finished we had a 3/4 air gap and drainage plane.

Install Flashing On Existing Roof To Extend The Lifespan Of Your Roof

Whether your drip flashing has been failing and allowing excess water into your home, or your step or vent pipe flashing is corroding, learning to install roof flashing on an existing roof is a great way to maintain the health of your current roof. Checking your flashing is just one step in performing a roof inspection, so be sure to keep up to date on the rest of your roof too.

If you need to install flashing on existing roof installations, but are unsure how, dont worry contact David Barbale home improvement services. David is a seasoned expert in the field of home improvement, including roofing, siding, flooring, and carpentry, and he can walk you through the entire process of how to install flashing on existing roof installations.

So dont let your home fall victim to rain or moisture. Contact David Barbale today, and keep your roof healthy and happy, for a long service life.

Recommended Reading: Cost To Reseal Rv Roof


Most Popular