Exterior walls

Common wall structure - wood/metal frame and solid masonry.

Common covering materials -  bricks (solid or veneer walls), stucco, aluminum, vinyl and wood siding.

Common brick walls  problems

  • Efflorescence – Efflorescence (white crystalline powdery substance - not mold) is a salt deposit on masonry or concrete surface that is associated with water/moisture moving through walls. Water in the walls dissolves salts from the mortar, concrete and masonry. As the water evaporates off the wall surface, the salts are left behind as crystals on the masonry. The efflorescence itself is often not serious, but it does suggest that water is in the concrete or masonry. Spalling may result if the water freezes in the wall.
  • Spalling. Spalling is a result of water/moisture entering brick, concrete or natural stone and forcing the surface to peel, pop out or flake off. This is crumbling or flaking of the surface, usually because of efflorescence, freeze/thaw action, or water or mechanical action (sandblasting or high pressure water washing. Water plays a large role in efflorescence and freeze/thaw damage). Eventually, spalling can cause crumbling and destruction of a structure.
Masonry walls. Masonry walls are typically comprised of two wythes (layers) of masonry, usually four inches thick each. A typical brick wall is approximately eight inches thick before application of the interior plaster or drywall. The inner wythe (layer) is most often brick, concrete block or cinder block. The outer wythe, exposed to the weather, is usually weather resistant brick or stone. A masonry wall is a load bearing component of the building that transfers the weight of the roof and floors down to the foundations. The foundation must be at least as wide as the wall to carry the weight of the wall system.
  • Cracked masonry and mortar. Cracking may be caused by –

           1.  Building settlement and foundation cracks (see foundation section).

           2.  Freezing damages (associates with water moving through walls).

           3.  Mechanical damages.

           4.  Thermal expansion and contraction.

           5.  Corroded doors and windows metal lintels. Expanding corroded steel lintels over

                windows and doors often cause horizontal and/or step cracks in masonry, radiating

                out from the top corners of the opening.

           6.  Bowing walls. Bowing masonry walls are more common on old buildings and are

                usually the results of failed fasteners holding a masonry veneer wall to the house

                framing or inadequate lateral support for solid masonry load-bearing walls.

 

Brick veneer walls are wood or steel frame walls with a masonry (full bricks) siding. A single layer of brick is built near exterior wall and attached to the house with metal ties. Veneer brick does not support the structural load of the building; if the brick were removed, the house would continue to stand. 

  • Bowing walls.Bowing walls are usually the results of failed fasteners holding a masonry veneer wall to the house structure or inadequate lateral support for multi-story solid
    masonry, load bearing walls.

 

  • Missing flashings and weep holes or wicks (veneer walls). Masonry veneer walls are provided with weep holes (or wicks) to allow water which reaches the back of masonry walls to drain out of wall system.

 

  • Too close to grade. Most bricks should be kept 6 inches above grade. Masonry and mortar may deteriorate as a result of the constant exposure to moisture.

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Stucco problems

Stucco is a mortar mixture used for siding. Stucco can be made by mixing sand and lime with water and various other ingredients, most often cement. Usually, wooden walls are covered with tar paper, insulation and chicken wire or galvanized metal screening. This framework is then covered with the stucco mixture. Sometimes, the mixture is applied directly to specially prepared masonry surfaces.

  • Cracks, crumbling, loose or bulging stucco. Stucco may be cracked, crumbling, loose or bulging because of many things, including:
Cracked stucco

          1.  Building settlement.

          2.  Water penetration into the wall system as

               a result of poor/missing flashing or

               caulking.

          3.  Differential expansion and contraction

               between the substrate and stucco.

          4.  Rusting metal lath or trim.

          5.  Lath fasteners that are rusted, too short

              or spaced too far apart.

          6.  Stress concentrations at openings

              (windows and doors).

          7.  Stucco too close to grade.

          8.  Leaky gutters.

 

EIFS problems. Synthetic stucco or "EIFS" (Exterior Insulation Finish Systems) has been used on thousands of homes. It differs from "real" or "hard" stucco by utilizing an insulated sheathing board and a fiberglass mesh. The EIFS layers bond to form a covering that doesn't breathe. The problem is water penetration, allowed to enter behind the EIFS, does not evaporate and is trapped. With no place to go, constant exposure to moisture can lead to mold, rot in wood sheathing, wood framing and other vulnerable materials within the home. Moisture related problems lead to individual and class action lawsuits by consumers.

                                                            Cracked stucco

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Metal and vinyl siding problems

           1.  Buckled or wavy. Both vinyl and metal

                siding expand and contract with thermal

                changes. As a result, the siding must be

                free to move horizontally. The most

                common installation mistake is securing

                the material too tightly, preventing it

                from moving.

           2.  Flashing and caulking defect. Water and

                vermin entry are the possible

                implications.

           3.  Loose. Siding may not be well secured to

                the wall.

           4.  Mechanical damages. Metal is susceptible to denting. Vinyl siding is more likely to

                split, especially when it gets cold.

           5.  Corroded. Modern metal siding is prepainted at the factory, but if paint is scraped

                off, the exposed steel may rust.



Wood siding

Wood siding types - Wood planks, beveled wood siding, wood shingles and shakes.

Wood siding material - cedar shingles and shakes, plywood, hardboards and OSB.                                      

 

  • Common wood siding problems:

           1.  Rot. Rot is a fungus, and the fungus

                spores are always in the environment

                ready to attack. When the moisture

                content of the wood is above 20%, and

                external temperatures are between

                40º F – 120 º F, rot should be expected

                Rot is caused by water penetration and

                poor wood drying.

 

 

          2.  Splitting. Split wood may be caused by shrinkage of the green wood (threated) as

               it dries, inappropriate nailing, mechanical damage and shingles/shakes butted too

               tightly together. Split boards or siding will allow water penetration into the building.

               Split wood exposes new unprotected (unpainted) surfaces to weathering and may

               result in rapid deterioration.

 

          3.  Warping. This usually results from – one side of the wood being wet and the other

               dry, the quality and grain characteristic of the wood.

 

          4.  Buckling (hardboard panels). Buckling may be caused by panels nailing too

               tightly and adjacent pieces butted to tightly together.

 

LP Inner Seal (waferwood) siding problem.

In 1985, Louisiana-Pacific introduced a siding product called LP Inner Seal, sometimes referred to as Waferwood. It is OSB, with a wax-impregnated paper covering, and is sold as lap siding or panel siding. A class action lawsuit was filed against the manufacturer over problems with the siding. The suit alleges the siding may prematurely swell, rot, buckle, check, crack, delaminate or support fungal growth when exposed to normal weather conditions.

                                                        Luisiana Pacific siding