Steel Studs for Interior Walls

Wood versus steel studs.

 As quality lumber becomes more expensive and harder to find, we're finding that more and more builders are framing their homes with steel. Both load bearing and non-load bearing steel studs are already used extensively in commercial construction.

Much of the wood we have now is warped and soft.  Often with wood studs when you look down the wall it waves back and forth. With steel they are deadly straight and accurate.  You pull a string across them and they are exact.  With interior steel studs you get flatter and cheaper walls."

While interior steel studs work quite well, there are still problems with them for exterior walls.  Structural steel studs for exterior walls provide poor insulating values.  In Minnesota, cold transferring through the steel presents heating and moisture condensation problems.

How do you install it?

You install steel framing much like conventional wood framing.  A basic system consists of galvanized C-shaped studs, joists and channels.  You use the channels at the top and bottom of the walls, similar to plates.  The studs fit into the channels, held in place with self-tapping screws.  Punched holes in studs allow for electrical wiring and plumbing.  Steel studs come in gauges, from 14 to 26 .

Common studs come in five widths:  1 5/8", 2", 3 5/8", 4" and 6".

Steel studs don't warp, split or burn and building with steel is fast.  Another advantage of steel is the clear spans it can breach.  Steel trusses when used on the main floor allow for 20' and 30' column-free spans in the basement.  The greatest advantage is the floor's strength.  An ordinary wood floor has about 40 lb. bearing load at legal deflection.  Steel carries a 127-lb load at legal deflection.

Troubleshooting Roof Leaks

The cost of installing the roof on a new building usually amounts to less than 5% of the total construction cost.  Yet some lawyers estimate that 60% to 80% of construction lawsuits involve roof failures.  Often, it's a small leak that quickly grows into a big expensive problem.

The following problems are among the most common that have been encountered.  In every case, the leak could have been avoided had the installer used common sense and paid more attention to detail.

Asphalt Shingle Roofs

Problem:  No drip edge. If asphalt shingles are installed without a drip edge, it's only a matter of time before the plywood sheathing and fascia begins to rot.  Water dripping off the edges of the roofing is drawn by capillary action to the exposed edges of the plywood sheathing.
Solution: Install a metal drip edge at rakes and eaves.  The main purpose of a metal drip edge is to interrupt the wicking of water to the sheathing edges.

Problem:  Felt underlayment incorrectly lapped under (instead of over) the metal drip edge.  Any water that may get under the shingles - for instance, from wind-driven rain - should be carried by the felt underlayment over the top of the drip edge.
Solution:  Lap the felt underlayment over the drip edge.

Problem:  Valley shingles were not tabbed or spotted with roofing cement.  The large volume of water that collects in a valley can back up under uncemented shingles.
Solution:  In a closed valley, embed valley shingles in roofing cement.  Always clip the top corner of the valley shingles at a 45-degree angle.  This prevents debris from getting caught in the shingles and accumulating in the valley, and it also will direct water toward the valley centerline.  For extra protection, install a self-adhering eaves membrane under valleys.

Problem:  Roofing nails.  Exposed roofing nails are sometimes a source of leaks.
Solution:  Cover exposed nail heads with a dab of roofing cement when exposed nails can't be avoided (as with cap shingles).

Problem:  Excessive shingle overhang.  An installer apparently believed that increasing the overhang on the first course of shingles would help direct the water into the gutter, and would substitute for the metal drip edge.  However, the shingles eventually crease under their own weight and break off, exposing the edge of the sheathing beneath.
Solution: Shingles should overhang beyond the metal drip 1/8 nch to 1/4 inch, according to recommendations from the Asphalt Roof Manufacturers Association.

Below-Grade Moisture Control

     Perhaps the most overlooked and challenging technical issue for the builder is foundation moisture control.  It is frequently overlooked because professionals and consumers alike fail to recognize the tremendous impact the below-grade moisture can have on overall building durability and indoor air quality.

     While there may be no simple answers, it is useful to review the various below-grade moisture issues.  First, it is important to recognize that many of the moisture problems we see in homes are a result of significant amounts of below-grade moisture entry, both liquid and vapor, into the home.  Second, it is helpful to isolate each moisture movement mechanism that ultimately contributes to building durability and indoor quality.

     Liquid flow by gravity is relatively simple and fairly easy to accommodate by properly draining rainwater away from the building.  Control measures include overhangs, gutters with extended downspouts, positive slope away from the building, porous back fill (or drainage mat) with an impermeable cap, a carefully installed drainage system at the footing, and a high quality damp proofing system.

     Hydrostatic flow results from water standing next to the foundation.  This can be due to large quantities of surface water saturating the adjacent soil or a rise in the ground water next to the foundation.  A properly installed foundation drainage system should be designed to quickly relieve this hydrostatic pressure.  If longer-term hydrostatic pressure is anticipated, a high quality waterproofing system must be used to provide resistance against hydrostatic flow.

     Capillary action or "wicking," is the flow of water through small pores due to surface tension and adhesion.  For below-grade moisture, the key capillary concerns are through the floor slab and from the footing to the foundation wall.  For the floor, use a layer of washed aggregate or impermeable membrane below the slab.  For the foundation wall, install a capillary break such as a waterproof coating or durable membrane between the footing and foundation wall.  For concrete masonry walls, it is important to keep the cores dry.

Water Vapor Flow
Diffusion of water vapor is a slow, but relentless, moisture movement mechanism.  Water vapor will try to travel from more to less.  In saturated soils, the water vapor moves from the ground into the foundation and home for most of the year.  Fortunately, diffusion is easy to slow with a vapor retarder.  A quality damp proofing or waterproofing coating or membrane on the foundation walls and a durable, impermeable membrane under the slab will generally control below-grade diffusion.