FINISHING AND DECORATING
GYPSUM WALLBOARD
Producing an acceptable, decorated, drywall surface has never been easy. Changes
in products, methods of application, and specifications have greatly complicated
that task. The drywall contractor must address those changes, and react to them,
if he is to produce an acceptable, and profitable, job.
To properly assess the drywall contractor's dilemma let's evaluate some of the changes
that have taken place and how they affect us.
DESIGN/SPECIFICATION
When vaulted ceilings and high walls first became the vogue there was absolute pandemonium
regarding design and framing procedures. Many of those problems have been diminished,
but are by no means solved. Likewise, the move toward trusses in roof/ceiling construction
has presented problems, as has the increased use of heavier roofing materials. Many
times it appears that the designer or structural engineer intended the drywall panels
to hold the entire structure together.
In the past few years there has been a definite tend away from aggregated ceiling
textures and, to some extent, away from texture altogether. Naturally, the decorative
treatment of the drywall surface dictates the type, and amount, of finishing required
prior to decoration. (It should be noted that texture should be considered decoration,
not a step in the drywall finishing process.)
PRODUCTS
The gypsum wallboard presently in use is considerably different than what you might
recall in the "good old days". The weight of the product has decreased
substantially. Reportedly, EPA mandated changes in paper manufacturing have resulted
in face paper changes which complicate the painting process.
Joint cements and spray texture products have also been affected by government regulations.
Types, and amounts, of preservations are closely controlled. The result may be
shorter shelf life on pre-mixed products, and increased risk of spoilage in spray
texture equipment.
Paints and sealers, again due to government decree, have undergone major changes
in formulation. In many cases, "side sheen" and "hide" have
been seriously affected. Solvent based products will eventually be unavailable.
METHODS OF APPLICATION
A significant percentage of gypsum wallboard is now applied with screw attachment.
This has evidently become necessary due to changes in the product which resulted
in so-called "loose board".
Spray texture equipment has changed almost
exclusively to stator tube pumping systems for material delivery. While these systems
are more efficient than the previous air pumps, the result in the lack of sufficient
air pressure/volume to properly atomize the texture material for application of a
fine "fog" texture pattern. It is our experience that a sustained 90 to
100 PSF is required to effectively apply this type of pattern.
In years past, the standard texture application was two coats; a "fog"
base coat, and a "splatter" second coat. Gradually, the market preference
changed to "knockdown" patterns, applied in one operation. In the recent
past, texture patterns have been reverting to lighter application which has contributed
to the problems of drywall finishing/painting. It is difficult to argue with the
"old way" of a "base coat fog" and a second coat "pattern".
The airless spray application of paints, combined with all of the other changes mentioned
previously, has been a significant factor in finishing/decorating problems. It is
our recommendation, based on field experience, that the first coat of paint/sealer
be applied by roller. Although that recommendation has not been favorable accepted
by painting contractors, we feel quite strongly that first coat roller application
provides enough benefit to justify the additional cost.
SUMMARY
In reviewing the foregoing, the drywall contractor must determine what factors he
can control, the relative cost in controlling them, and who is going to pay those
costs. For instance, he does not design the structure nor, in most instances, does
he frame it. How much structural cracking, joint beading, etc., does he repair before
charging for his costs? How many walls and ceilings does he re-texture because of
the change to airless spray, and paint problems?
In separate bulletins we are offering our recommendations to assist our customers
in alleviating some of the problems outlined above. We also suggest that you become
familiar with, and follow, the recommendations of the Gypsum Association, the American
Society for Texturing and Materials, and the manufacturer of products used in conjunction
with ours.
Enclosures
Issue Date: 7/90