WallNet-F

The process begins with eliminating water and electrical supply to the areas where work will be performed to allow the safe removal of all wet and damaged building materials from the inside of the structure.  After removal of the damaged materials, the drywall, polyethylene (if present), batt insulation, exterior sheathing and any rigid insulation that may exist is pulled through the studs and properly disposed of.  Once the bulk material is removed from the wall, the sheathing that is remaining between the wall ties and the studs, as well as mortar droppings at the base of the wall are removed.  Any products that are used to prevent mold would be applied now, along with fans to assist drying remaining materials.

There are a few steps that can be taken to shorten reconstruction time.

One step that can be performed is to remove damaged materials vertically in 2-foot increments and 6 inches above the highest recorded water level.  The incremental measurements will reduce material waste, simplify cutting and make the project easier to compute required materials.

The second important step is to inspect all wiring connections and plumbing lines within the interior of the walls prior to reconstruction.  Plumbing and electrical lines will have pressure applied to them as the demolition process takes place and can result in the need to tighten and reconnect fittings. Inspect electrical junction boxes for debris or mud, as it often can accumulate in the lower areas of the walls. Wall ties should be inspected and evaluated for integrity.  If the wall ties are slightly loose the application of the closed cell foam, described later in this article, will compress between the wall tie and the stud offering a tie that can resist lateral pressures. The local building inspector (Code Official) will typically determine acceptance of current in place ties and recommend what they require for your jurisdiction.

Applications that require post applied façade anchorage can be completed using ties engineered and manufactured by Construction Tie Products (www.ctpanchors.com ).  CTP offers an anchor that is attached to the interior stud and drilled into the inside face of the brick façade. The helical anchor installs efficiently and is very cost-effective repair anchor. The anchor does not disturb the exterior of the building and all the hardware is concealed within the building envelop. The retrofit tie is stronger than the original mortared tie that is in the original brick façade (typically light gauge corrugated), while the bracket is supplied with the required hardware for a stable connection to the existing stud (wood or metal).  This anchor is easy to install and offers the building owner a sound and well performing anchor.  Once the walls are dry and inspected the placement of new wall components can begin.

Third on the list of how-to is to drill a series of 3/8-inch holes in the into the façade head joint at the brick shelf level. Once the series of holes are drilled, the head joint can be cleaned out using a small chisel and a Mortar Net Solutions WeepVent™ can be placed into the head joint allowing the wall the ability for air and drainage to move freely through the cavity. The brick shelf is located at the bottom of the wall where the brick sits on a small recessed ledge at or just below the finished floor level.  This brick ledge is where the through wall flashing is found, if the original builder installed it.  Weeps should be drilled based on your local building code standards (typically less than 33 inches) but it is recommended for them to be placed at 24 inches on center, that works out to every 3 brick head joints (head joint is the vertical joint found between in-place masonry units).  The weeps must be drilled with no smaller than a 3/8-inch diameter masonry bit and beginning at the bottom of the bed joint (the bed joint is the horizontal joint found between in-place masonry units) located on the brick shelf.  The reason this is important is because if the weep is drilled above the brick shelf, say ¼-inch above the brick shelf, then ¼-inch of water will need to accumulate in between the inside framed stud wall and the inside face of the brick (this is called the wall cavity) before drainage to the exterior will occur, creating an everlasting puddle of water that can create big trouble for the homeowner.

Whether the original builder installed base wall flashing on the brick shelf does not matter at this point, either way fluid and gunnable (able to be placed using a 20-ounce caulking gun) FastFlash® by PROSOCO.  It is a polyether material that is released from the caulking gun and troweled smoothly into place to create a flexible flashing that will direct any water that accumulates at the interior base of the cavity wall into paths to the weeps and out of the building.  This is important because even though the wall will be dry during construction, the brick will allow moisture to pass into the cavity throughout the life of the structure, therefore, always needing a way to weep the future moisture from the cavity.

The fifth step in this process and most important, once all inspections have been completed, Mortar Net Solutions WallNet-F™, a new concept in cavity drainage and ventilation, can be placed in between the studs in all exterior walls.  WallNet-F is an entangled mesh that automatically creates a ventilation and drainage channel that fits and fastens with staples vertically in between the studs. The attached fabric will preserve an open cavity by blocking the closed cell foam insulation from entering the mesh.  Moisture that passes through the wall veneer and into the cavity now have a dedicated and clear path to drain to the weeps.  The WallNet-F is precut to fit around existing wall ties and designed to be end butted as more vertical pieces are required.

Once the WallNet-F is secured by fastening to the studs, installation of the closed cell foam can occur. It is important to hold the foam back about an inch from the inside face of the studs. The space that remains between the installed foam and inside face of the drywall can easily allow for communication cables to be installed later.

In completing the wall rebuild, and once the second wall inspection has been approved, the drywall installation can take place.  If the original construction utilized a layer of polyethylene between the stud and the drywall, it would be an important to consult with the local building official to determine if replacement will be required by the local codes.