Questions and Answers
 
What is the Difference in Stucco and EIFS?

Stucco is a mixture of generic cement; sand and sometimes lime. EIFS is a proprietary exterior wall cladding system using a polystyrene base, modified acrylic: cement basecoats, fiberglass reinforcing mesh and acrylic texture: color coats.

 
What is the Difference in Control Joint and Expansion Joints?

A control joint is intended to relieve stress and limit or control the cracking in the membrane of the stucco only. Usually installed at a maximum of 144 square feet. It is not necessary and in fact can be detrimental to cut the lath behind the control joints. A control joint will not stop stucco from cracking if the stresses imposed upon the stucco membrane are greater than can be dissipated by the stucco and/or the control joint.

An expansion joint is a two-piece slip joint that is installed at a similar expansion joint in the structure of building. When installing an expansion joint, the framing, sheathing and lath should be cut to create a true plane of expansion.

 
How do the costs of three-coat stucco and EIFS Compare?

Since there are so many variables with regards to size of job, logistics, scaffolding, etc., it is hard to give a straight answer to this question. However on an average wall area, the costs are somewhat similar with the standard EIFS generally being more economical. If there are additional trims such as cornice, quoins, window bands, etc., then the EIFS can be much more economical than the traditional stucco. If there is a need for resistance to high impact or expected high traffic at the location, the traditional stucco wall may be cheaper than the EIFS with extra layers of reinforcing mesh.

 
What is fog coating?

Fog coating is simply application of a stucco finish over the existing finish. Rather than being trowel applied, the stucco is spray, brush, or roller applied. The stucco fog material is identical to the stucco finish that was trowel-applied over the original brown coat. The only difference is that aggregate is omitted from the mix (sand, perlite, etc.)

 
What is the durability of exterior Portland Cement Plaster?

It performs for the life of the structure.

 
How does the quality of veneer plaster compare to dry wall?

No comparison. With drywall, only nails and joints are covered with a soft compound. Veneer plaster coats the entire surface with a hard durable finish. The veneer job looks much nicer. Some drywall jobs look perfect too, but give them a few years and they often develop ridging, beading and nail popping.

 
What is the primary cause of cracking in Stucco?

A concentration of stresses, which is magnitude, exceeds the strain capacity of the plaster. What cracking occurs in Portland cement plaster (stucco), there is one primary cause.

With this lack of stress, Stucco properly mixed, properly applied, and moist-cured, offers indefinite performance on any building in virtually any climate.

 
Besides stress, what are some of the other main reasons that might cause Portland cement plaster (stucco) to crack?
  • Lack of proper moist curing.
  • Failure to gap wood based sheathing panels.
  • Poor mix formulation: too much water in mix, poor choice of sand.
  • Too thin a plastic membrane
  • Poor workmanship
 
What is the difference between a weep screed and a drip screed?

The purpose of a "weep" screed is to allow any water that reaches the back plane of stucco via openings between stucco terminations and dis-similar components, faulty or absent flashing, and the like, to run downward and escape at the bottom of the wall. The water runs between the stucco and building paper and escapes to the outside. Weep screeds are required at foundation plate lines by building codes.

A drip screed is a device that directs water downward, like at an external wall/soffit angle. Drip screeds keep water from running laterally at the soffit, but they are optional. A "V" groove in soffit stucco about an inch back serves the same purpose.

 
Should a water repellent be added to Portland Cement Plaster?

Portland Cement Plaster is NOT a porous finish through which water passes readily. In fact some list have shown that water-repellent compounds may actually retard cement hydration and increase permeability. Stucco does not permit passage of water through it unless it is extensively cracked with severe cracks.

 
Can plaster be applied directly to concrete or concrete block surfaces?

Yes. When applying Portland cement plaster, make sure all surfaces of the concrete or concrete block are thoroughly clean, free of form oils, coalings, dirt, dust, or any element that can nullify bonding.

 
Why use acrylic modifications in a Portland cement plaster?

Polymer modified Portland cement plasters provide unparalleled strength, greater durability, excellent adhesion to substrata, and preclude the need for "moist curing". Acrylic modifiers offer these distinct benefits:

  • Unequalled bond strength
  • Superior mechanical strength properties
  • Excellent water resistance and abrasion resistance
  • Superior freeze/thaw resistance and proved long-term durability on exterior exposures
  • Unequalled resistance to discoloration. Good chemical resistance
 
When do you repair cracks on a new building?

Most stucco cracking takes place in a matter of weeks after application to new construction. During and shortly after construction, stresses in buildings can be significant. At the same time, plaster has not developed its ultimate strength. Consequently, stresses can cause considerable cracking. After plaster has gained strength, at the same time stress generation in a new building has subsided and stabilized, any repairs made after several months have a better chance of doing their job.

 
Should I always take a Low Bid?

An "unusually low bidder" is a subcontractor who consistently turns in a bid for plaster work that is 20%, 30% or more lower than the average of bids. These are often people who take "shortcuts" that will inevitably show up on installed work or they overlook something and will not want to complete the project if they get the project and realize their mistake. When bids are close, a low bidder is a logical choice if it is for a qualified contractor, but when an "unusually low bid" is encountered, it should be a signal to beware.

 
What is the "R Value" of Stucco?

For a non-insulated stucco assembly it is an R=0.15.

 
What is the intention of Control Joints?

Control Joints are intended to create artificial planes of weakness where stresses in the plaster membrane can dissipate without forming their own cracks, breaks, or fissures.

 
What is the criteria for selecting a Quality Lathing and Plastering Contractor?
  • Is the contractor a member of a professional association which sets standards and is recognized in the construction community, such as the Texas Lathing and Plastering Contractors Association?
  • Is the contractor bondable?
  • Will the contractor provide a list of previous jobs similar to the one you are planning?
  • Can the contractor meet the financial terms and time schedule involved?
  • Is the contractor an approved applicator of the method or system being specified?
 
Does Stucco need a Sealer?

Sealers for stucco are unnecessary. Stucco is already "waterproof." Using a sealer on stucco affects bond of a stucco fog coat, which you may want to use to redecorate surfaces at some later time. Sealers wear off due to U/V light and will need maintenance.

 
What is One Coat Stucco?

One Coat is a blend of Portland cement, sand, fibers and special chemicals, which will produce a durable, cost effective exterior wall treatment.

One Coat Stucco provides design flexibility, durability, versatility and cost savings and it can be finished in a variety of ways including premixed cement finish coats, elastomeric coatings and even the synthetic finished used in conjunction with EIFS. One Coat Stuccos' impact resistance is good, with an average of 2500 PSI. One Coat Stucco combines the "scratch and brown" into a single application of 3/8" to 1/2" thick coat. One Coat Stucco weighs only 5 - 6 pounds per square foot.

 
Can I apply One Coat Stucco on any home?

No, one-coat stucco is not a Do-It-Yourself Product and must be applied by a certified applicator who is certified by the manufacturer.