Siding guide · Reviewed September 2026
What Is House Wrap?
The role of weather-resistive barriers and why installation details matter.
House wrap is one part of the water-control layer
A weather-resistive barrier is intended to help manage water that passes the cladding. It must connect with flashing, tapes and other components so water is directed outward rather than trapped in the wall.
The product name alone does not establish performance. Continuity, laps, penetrations and transitions determine whether the layer functions as planned.
Openings and penetrations require sequencing
Windows, doors, vents, meters and roof-to-wall intersections interrupt the barrier. Flashing is generally layered to shed water, but the exact sequence depends on the opening, existing construction and selected products.
Ask the contractor to describe how existing window details will connect to the new work before siding covers the assembly.
Replacement scope depends on what is exposed
Full siding removal may allow the existing barrier and sheathing to be reviewed. Overlay projects expose less of the wall and may carry different assumptions.
The quote should identify whether the barrier is retained, repaired or replaced and how concealed deterioration is handled.
Primary reference
This external source provides additional government or building-science context. Product-specific instructions and an on-site assessment still govern an individual project.
Natural Resources Canada guidance on exterior wall assemblies