Painting Popcorn Ceilings
To the Editor:
The answer on how to paint popcorn ceilings, or sprayed-on acoustic (Q&A, 7/02), was right on as far as it went, but a couple of issues were not addressed.
Acoustic ceilings continuously shed, so if they're dirty, why not strip them? It's simple: Mask off the room, walls and floor. Spray the ceiling with a mix of warm water and detergent until soaked, using a Hudson Sprayer. Move a large garbage can lined with a plastic bag around the room and, using a broad knife, remove the acoustic. It will come off like damp cereal and with care will drop right into the plastic bag. A room will take only a couple of hours. Then a new clean job can be installed without the corn.
Most seriously, these ceilings commonly contain asbestos and should be tested before anything is done, including painting, that will blow acoustic dust around. (A test costs around $25.) Wet removal prevents the material from becoming airborne and is better than painting, but contractors should make sure all regulations are followed.
My advice, if it's not commercial space, is to get rid of the stuff.
Karl Kardel, Consultant
San Francisco, Calif.
Repairing a Stone Foundation
To the Editor:
I want to commend David Rippe for a fine article ("Repairing a Stone Foundation," 7/02) and for his answer to a remodeling problem. It's obvious that he's a problem solver who looks for ways of doing things instead of reasons not to. Some people in the field would likely call him a maverick; I would say he is a can-do person who weighs the considerations at hand and uses his head to the benefit of the customer.
Reading the article reminded me of some similar projects I have done but also broadened my repertoire of ways of doing things.
My favorite line in the article is "You want to do what, now?" Boy, did that ever ring a bell. I wish David and his partner, Art Rombauer, a wonderful career.
Les Deal Inc.
Cedar Rapids, Iowa
To the Editor:
The first thing to catch my eye on the cover of the May 2002 issue was how the starter course of shingles was being run. I don't know of any manufacturer who instructs the installer to spin a shingle around to use it as a starter course. The tar strip needs to be at the bottom of the shingle to seal the tab down, which is achieved by slicing off the tabs and sliding the shingle down. You won't get a good seal if the tar strip is in the middle of the shingle.
Garage Floor Finishes
To the Editor:
Some months ago, we received a call from one of your staff asking us to contribute photos for an article you were doing on garage floors (Trade Talk, 2/02). Since this is an important part of our business, we quickly complied. In fact, you used one of our photos on the first page of your article. However, no one called for our technical input in developing your article.
Quotes by apparently less sophisticated formulators, such as "never use a water-borne epoxy for a garage floor," mislead your readers. If you had asked us, you would have learned that our state-of-the-art water-borne polymer garage floor system will perform as well as traditional heavy-duty industrial coatings in every aspect. It is unaffected by hot tires and is impervious to solvents, including brake fluid and gasoline. It is extremely stain resistant and will not show tire stains after it has cured. Furthermore, Supercoat exceeds all traditional floor coatings, in that it breathes and can be installed in areas with excessive moisture vapor transmission, up to 10 pounds.
The article states that "a smoothly troweled concrete slab needs to be roughed up by either acid washing or shot blasting." Supercoat's adhesion to concrete is far greater than traditional floor coatings. It will stick to unprepared but clean concrete, even steel-trowel finish, without mechanical or chemical abrasion. Supercoat's adhesion to plate glass is over 450 psi, based on ACI Test Method F1869, Elkometer.
Kent Speers, General Manager
Oklahoma City, Okla.
Cracked Manufactured Stone
To the Editor:
I am writing regarding the question on cracked manufactured stone (Q&A, 6/02). I have worked in the plastering trade for more than 20 years and am currently a supervisor for a San Francisco Bay area plastering company.
The manufactured or faux stone will perform only as well as the substrate it is applied over. This includes the foundation system, the framing system, the lathing system, and the plaster, if any, applied over the lath. Experience has shown me that noncontinuous wire lath has a great tendency to allow the stucco over it to crack. This cracking can extend through stucco, tile, faux stone, marble, or whatever.
In my opinion, the vertical cracks are from the wire lath not being lapped at the corners. The UBC specifies that all lath be lapped; however, corners need not be lapped if corner-aid is applied. The use of thin wire may also contribute to this cracking. Standard wire lath is either 17 or 18 gauge. The use of 20-gauge material is common and contributes to the problem of cracking.
The thermal stress increased the chances of this stress crack appearing. The timing of the appearance of the cracks also indicates to me that this was a structural (underlying) problem and not a problem that developed later, when the moisture content of the beam dropped. The lack of integrity of the lathing system allowed the stresses to manifest almost immediately as a crack. These cracks will now allow moisture to enter, and a new stress will be added -- the swelling and shrinking from the framing alternately getting wet and drying out.
I strongly recommend two layers of paper and 17-gauge 1 1
/2-inch self-furring stucco netting. I also recommend the use of furring nails and of weep screed (which can easily be hidden by the faux stone) to prevent capillary action. With a properly constructed substrate, your cracking problems should vanish (on the next house). Rick Rutherford via e-mail