Flashing Under Cedar Siding

Step flashing is used where a roof meets a.

Flashing under cedar siding.

Building siding flashing finish details for building corners use overlapping 1x4s or 1x6s at outside corners or use 5 4 stock for a heavier look. Cedar shingle siding must never rest on the horizontal surface of flashing. Keep water out of your home and running down the roof where it belongs with appropriate use of step flashing. Fiber cement boards are caulked only when there is no metal flashing behind them.

Failing to replace step flashings when a cedar shake roof is replaced with a composition shingle roof. It is always recommended to install step flashing behind stucco dryvit wood panel lap siding vinyl siding cedar shingle siding etc. We only caulk butt joints on cedar siding if previously caulked. Install the flashing before you finish the top of the brick wall as the flashing must go behind the siding as well as behind and under the top row of bricks that angle outward to cover the top.

Flashing intercepts and directs the flow of water away from the building to designed drainage paths. A common problem with cement board siding products and some other types of horizontal lap siding is that older installation guidelines called for caulking the joint instead of flashing the joint. Otherwise it is possible for water to wick up the shingles and into the wall. Flashing must be overlapped by the moisture barrier.

This has proven problematic over time as caulking the joint results in unsightly surface appearances due to the different textures as well as resulted. Natural siding boards are designed to expand and contract with the elements and we do not want any adhesive to prevent their natural movement. Flashing is an important line of defense in controlling moisture in wall assemblies. Use a felt paper spline wrapped around the corner and extending 6 inches beyond the corner board to protect the joints where the siding meets the corner boards see figure 1 5 at left.

You do have to trim the top starter course shingle with a triangle shaped cut to allow this. Inspect the sidewall around and underneath the fascia and inside the house for signs of moisture damage and repair any rotted areas. Step flashings on a cedar shake roof are typically installed every 10 inches. The top of the step flashing is still under the siding or plaster.

Put the bottom step flashing on the starter course then bend the bottom of the step flashing out about 1 to 1 away from the wall. Flashing should be made from a non corrosive material and should extend a minimum of 2 vertically up the wall. Before installing siding make sure that flashings are installed to prevent moisture from entering wall and roof spaces.