One would assume that participation in the forums of HGTVPRO would help bring together "PRO's" from arund the country to discuss issues and techniques that are relevent to our "Profession". There's also the bringing together of homerowners and professionals, allowing the non-professional to gather information that would be outside their knowledge base. Sometimes it's easier for non-professionals to ask a question anonymously, without any fear of feeling stupid. But, no question is stupid, they are relevent to everyone. Questions are the starting point of knowledge. On an open forum, everyone has the opportunity to read all posted information. So, one would think that coming to the HGTVPRO site would allow "Pro's" to communicate and distribute their knowledge base to everyone. This doen't seem to be the case. I was tought that a Professional brings together fact and skill. So it's important that facts, be based upon facts and not assumptiuons or what one believes to be true. Skill is based upon God given talent and practice. Everyone knows that if you ask 1000 people how to do something you would get 1000 different answers. Proving that techniques are unique to each individual profesional. Facts are facts though, and "Professionals" should not give absolutes if there is compelling facts to state otherwise. Many people will read the post and make decisions based upon the facts given, weather or not they have been checked or verified. There is nothing wrong with not knowing everything. Nobody knows everything, but everybody knows somethings. As a professional myself, I find it my duty to reasearch, fact check and verify information as it pertains to my field of expertese, and I chalange all my fellow "Pro's" to do the same. Debate encourages fact finding, fact finding encourages proven methods, and proven methods encourages consistant results. I started this thread because of a response for Richard Hetzel. He stated:
"Gypsum board will have a negligible effect on joist stiffness, and the difference between 1/2 and 5/8 will be even more negligible.There is no reason to use 5/8 on a ceiling"
This is not based upon fact. The fact is that:
"It is always a good idea to consider the performance (i.e., vibration, bounce etc.) of any floor system. Currently, there are no true industry standard guidelines to use for I-joists or dimensional lumber but there are several practical aids that have shown to be useful. Some are design aids, some are installation aids and (unfortunately) some are retrofit aids. They are offered as tools to help you minimize floor performance complaints but can not be guaranteed to eliminate all floor performance problems. Begin by using the concepts of fundamental natural frequency and damping when designing floor systems. The fundamental natural frequency (FNF) is a measure of how the floor vibrates when you walk on it and is measured in cycles per second (called a Hertz or Hz). Damping is a measure of how quickly a floor stops vibrating and is expressed as a percent between 1% and 100% (most residential floors have a damping range between 5% – 25% damping). Our bodies are extremely sensitive to vibrations below 9 Hz so the ideal floor would have a high FNF with high damping. Most problem floors have a combination of a low FNF (below 9 Hz) and a low damping (around 5%). The following list will help you determine the effect of different parameters on floor performance. It is the combination and interaction of these parameters that determines how the floor “feels”. DESIGN PARAMETERS EFFECT ON FNF EFFECT ON DAMPING ■ Longer Spans significantly lowers little or no effect ■ Higher “L over” deflection limit (L/480 vs. L/360) significantly increases little or no effect ■ Using an absolute upper limit on live load deflection significantly increases little or no effect (Usually between 1⁄3” to 1⁄2” max) ■ Using deeper I-joists increases little or no effect ■ Reduced on-center spacing increases little or no effect ■ Adding perpendicular partition walls little or no effect significantly increases ■ Increasing overall weight of floor significantly lowers significantly increases INSTALLATION PARAMETERS ■ Unleveled bearings (walls, beams & hangers) significantly lowers significantly lowers ■ Direct applied sheet-rock ceiling significantly increases significantly increases ■ Thicker sub-floor increases increases ■ Screw & Glued sub-floor increases increases ■ T&G sub-floor increases increases RETROFIT PARAMETERS ■ I-joist mid span blocking (one row) little or no effect increases ■ 2x4 flat on I-joist bottom (perpendicular) little or no effect increases ■ 2x4 strong back on I-joist bottom (perpendicular) increases significantly increases (vertical 2x4 nailed to side of flat 2x4)"
Also concerning the difference in between 1/2 and 5/8 sheetrock: Effective Stiffness (EI)* (typical range) Board Thickness (in.) Lb·in2/in of width N·mm2/mm of width 1/2 1500 to 4000 220,000 to 580,000 5/8 3000 to 8000 440,000 to 1,160,000
Also, why does EVERY gypsum panel manufacture make a 1/2 inch no sag ceiling panel ? Because 1/2 drywall has a tendancy to sag when applied on the ceiling, although conditions worsen the effect, such as joist spacing and the application of water based finishes. So inregard, advice from a "Pro": use products which are intented to outpreform not meet the criteria for installation. Now, everyone knows, that their are options for application of drywall to a ceiling. If your not sure still, reasearch, fact check and verify.
Posts: 41 | Location: new york | Registered: 20 March 2006
But without knowing any information about the one structure, to make a blanket recommendation to use 5/8 gypsum board makes no sense.
There are millions and probably billions of square feet of 1/2 inch gypsum board ceilings in existence, and most perform perfectly well. There are billions of square feet of ground floors with no gypsum board whatsoever on the basement ceiling, and most perform perfectly well.
This reminds me of a case on one of my projects where plans were approved and a building permit issued, and the contractor proceeded to build a foundation of 8-inch blocks, according to the plan. The building inspector came on the job and stopped the job, demanding that the foundation be built of 10-inch blocks.
When asked why he was making this request, his answer was "10-inch blocks are better".
The fact is that 8-inch blocks were perfectly adequate for the peoject, and conformed to code, and anything more would be overkill and a waste of my clients' money.
So too is a blanket recommendation that all ceilings be 5/8-inch gypsum board. In MOST cases, there simply is NO NEED.
Architect (NY) and Home Designer (PA)
Posts: 2483 | Location: Tobyhanna, PA | Registered: 24 October 2005
In many if not all counties in the state of Florida 5/8 gypsum/sheetrock is a manditory code requirement not just for structural reasons but for fire codes. In our county 5/8" "fire rated" sheetrock is manditory in all new homes and additions.
Posts: 79 | Location: Panama City, FL | Registered: 05 April 2006
Hi ,this is whisky,on your disscusion about sheetrock i am putting in a second floor bathroom and this is my first time doing tile i have put down 3/4inch plywood,had plumber do pluming,frame up a wall. Will put in corner shower stall,pedastel sink,toilet. what is the procedure for doing floor(i.e.thinset,backerboard,infloor heating,more thinset,then tile,grout ,i was thiking of putting down a membrane to protect ceiling below green board on wall behind showerstall,painting existing walls with paint If i have left anything out please let me know, thank,s whisky
