Concrete Spalling Behind Siding

James hardie recommends that a slip sheet joint flashing is installed behind each butt joint in the siding.

Concrete spalling behind siding. Spalls can appear because the rebar has been exposed and humidity and water have begun to rust the rebar or because the concrete joints were improperly built. Spalls may be 150 mm or more in diameter and 25mm or more in depth and the occurrence of smaller spalls also possible as per aci 302 1r 4. While spalling can occur on concrete it s especially a concern on stone brick or block where portions of the assembly can degrade to a point where they crumble. Mix one part type 1 portland cement and one part fine sand by volume.

Concrete spalling typically begins when the steel reinforcing embedded within the concrete member rusts. It also provides a. 7 inch wide smooth lap siding primed about 1 50 per square foot picking the right siding for your house is a delicate balancing act between good looks durability maintenance and affordability. Contrary to popular belief concrete is porous.

Spalling is break away of concrete surface which often extends to the top layers of reinforcing steel. This is a 6 wide piece of weather resistive material to make sure that no water gets through. Before that dries mix three parts fine sand and one part portland cement in your wheelbarrow with enough water to make the mix the consistency of thick oatmeal. Contractors might make the mistake of adding too much water but frankly most don t make mixing errors.

Most contractors will remember to do this but some of them try to save a buck by cutting squares of building paper for. Without both of these elements the steel bar does not rust. Add water until the mixture is the consistency of thick paint then brush it on the damp concrete. Spalling of concrete affects a broad variety of structures including framed buildings multi storey car parks bridges jetties tanks and bunds.

Spalling also can be caused by freeze thaw cycles in concrete and masonry products that have a high moisture content. Spalling that occurs in a concrete driveway or sidewalk typically happens because the weather changed during the hardening process or something else occurred to prevent the concrete from finishing its curing. The wood that goes under residential siding exterior sheathing performs several functions. Rusting of the embedded steel reinforcing occurs when that reinforcing bar is exposed to water and air.

Hydrostatic pressure is not the only cause of spalling. As weather changes the concrete expands causing it to spall which leads to further deterioration.