How Much Flashing Must Be Behind Cement Siding And Roof

Fiber cement boards are caulked only when there is no metal flashing behind them.

How much flashing must be behind cement siding and roof. The solution to rotting sidewalls is a small piece of bent metal called a kickout flashing at roofing suppliers which simply directs all that water away from the wall. On a wall to be covered with wood cement board vinyl or metal. The water runs down the siding and at the bottom of the first row of vinyl siding it drips off and contacts the metal flashing as it runs across the top of the fascia board. It requires no nails.

Flashing a wood framed chimney is like flashing a dormer except there s no roof behind it to direct uphill water away without protection water can leak into the joint and rot your walls. A 5 inch wide flashing will result in a 2 1 2 roof deck flange and 2 1 2 vertical wall flange. When he shingled the new roof he just used roofing caulk where the shingles meet the wall no flashing of any kind. Even if the roof has been properly flashed against the sidewall this one hasn t water can still run down the side of the house and behind the siding causing rot.

I had a contractor build a shed roof on the back side of my carport that extended over and attached to the house. We only caulk butt joints on cedar siding if previously caulked. The following series of pictures will detail how to make a simple flashing that can be slid up behind the joint. Extend step flashing at least 4 inches up the wall from the roof deck and at least four inches out along the roof deck irc 2015 and integrate the flashing with the drainage plane above for example overlap house wrap over it.

If metal the flashing should be made of galvanized steel at least 0 019 inches thick irc 2015. The water then runs off the flashing because it can t go up the flashing as it extends up behind the siding. 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. With the flashing in place let s see what happens.

The recommended width of step flashings will vary depending on the agency entity being referenced. Natural siding boards are designed to expand and contract with the elements and we do not want any adhesive to prevent their natural movement. The part of the house that it is attached to is wood lap siding. Further your step flashing pieces need to be 10 inches 254 mm long and at least 2 inches 50 mm wider than the exposure of the shingle you re using.

Depending on the reveal of your siding the flashing length will be inch less than the reveal. I m afraid that with time that rain is going to find its way between the roof and the wall and.