Replies

1. 
   YesMaam27577 | Feb 01, 2003 03:10am | #1

   Speaking generically, fiberboard does not hold a screw well, unless you use a plastic anchor.

   OSB is a bit better, but only when the screws go into the face -- never into the edges.

   If really depends on what you want to hold with the screws, and on a bunch of other factors.

1. 
   jonhomes | Feb 01, 2003 06:49pm | #8

   We've had bad experiences with osb.  We now refer to plywood as the real (expl. deleted).

2. 
   CAGIV | Feb 01, 2003 04:01am | #2

   What are you using it for?

3. 
   Piffin | Feb 01, 2003 04:45am | #3

   Can't answer accurately without knowing what you are using it for. Your description only tells us that you will empty a box of screws into the material. Usually people are using those screws to do something. What is your application? Hope nothing illegal or immoral is keeping you from telling us.

   ;)

   .

   Excellence is its own reward!

1. 
   TheOldCynic | Feb 01, 2003 07:51am | #4

   Putting down Pergo

   Its the new way, dinja hear?

   Doc - The Old Cynic

2. 
   Zano | Feb 01, 2003 06:09pm | #5

   I'm usiing OSB as a backer board for drywall butt joints.  Contemplating MDF, just wondering about the disperity between the two - which would hold the sheetock better.  I know that OSB holds it much better, just wanted your thoughts on the differences between the two.  I'm a drywall contractor.  I have read your past posts on butt joints, one thing, never ever leave a butt joint over an opening such as a door, window, etc.  When you nail or screw the board to the header on the opening, the header will eventually bend cracking the drywall; that's why one sees many cracks on the corners of openings.

   Want to say, I find this board very informative, entertaining and the people are very cooperative!

1. 
   baseboardking | Feb 01, 2003 06:16pm | #6

   Use 4ply plywood,probably 5/8cdx.Baseboard been VERRRY good to me

2. 
   andybuildz | Feb 01, 2003 06:25pm | #7

   Zano

           Just curious....why not throw a cripple in if its missing above a door or window? If you dont want to deal with that then why not use plywood.....its certainly easier to shoot screws through.....And oh yeh, welcome to Breatime.

   Be well

            Namaste

                          Andy"Attachment is the strongest block to realization"http://CLIFFORDRENOVATIONS.COM

3. 
   Piffin | Feb 01, 2003 10:16pm | #9

   My past comments were apparently uninformed. I've learned from others on this board of the advantages of this idea.

   For your purposes, I have no doubt that the OSB would be better.

   It is the less expensive and the MDF make sa lot of very nasty dust when you rip it up. The slick surface of the MDF would not hold adhesive as well either if you do glued installations. The MDF will probably chip out easier around the screws, being more flaky, for this semi structural application.

   Excellence is its own reward!

1. 
   Zano | Feb 01, 2003 11:58pm | #10

   Jon Homes,

   What bad experiences with OSB  - let me know will ya!

   Andy Clifford,

   'throw a cripple' - what do you mean by that? 

   Piffen,

   USG Gypsum Construction Handbook recommends leaving a butt joint between the studs to "minimize ridging".  Why we in wood framing jobs join sheetrock on a 1 1/2" stud that is probably twisted, not straight and subject to shrinkage and forces is beyond me.  We splice wire, pipes, wood - why not drywall?  Splice it  in between the studs/joists and essentially now you have one long piece of drywall not subjected to  forces, eliminate shrinkage (wood studs normally contain 19% moisture, OSB only 4%), the two butt boards are evenly aligned next to each other, etc.    Since OSB is  cheaper than plywood, although plywood can also be used, it's ideal for this "semi-structural" application.

   I've talked to a few rockers throughout the USA and a few use 2x4's as a backer just to gain speed in rocking.  Since I'm new here, can one plug one's own website on this forum?

   I've come to the conclusion that a 4 or 5 inch strip of OSB (cost of $0.25), plywood, etc., will bind the butt boards much better than an 1 1/2" stud, eliminate butt joint ridging/cracking.

   However, for the past two months on my jobs I'm using drywall as the backer - works fine, just need to fine tune one item.

1. 
   andybuildz | Feb 02, 2003 12:01am | #11

   forget termonology (cripple)....My original post also asked ......why not just use plywood"Attachment is the strongest block to realization"http://CLIFFORDRENOVATIONS.COM

2. 
   Piffin | Feb 02, 2003 12:24am | #12

   Right, I got convinced of the idea previously when this subject came up.

   My strip of osb would come closer to eighty or ninety cents though. But most jobs have plenty of off cuts of either osb or plywood sitting around that can find use here.

   Your website.

   The deal is, if I understand it right, that if you are selling something through your website actively, it is regarded as spamming the forum and not tolerated.

   If it is a point of contact and information about yourself or your business, there are a lot of posters here who include a link to their site, either in their signature line or in their profile. To enter it in either, click on your name above and then click "edit..."

   If it is considered spam, you'll be told soon enough, at which point you can politely apologize and say that piffin said...before removing it.

   LOL.

   Excellence is its own reward!

3. 
   Zano | Feb 02, 2003 01:07am | #13

   Andy,

   I see your from Long Island, I'm in Jersey, now I got your attitude  ;-)

   Nice site you have!

   Piffin,

   I'm not interested in peddling it here, I just want to understand and solve the only problem in drywall that I used to have - which was the butt joint.   Also, I have questions on why things happen in drywall and you fellas/gals seem to know a lot.  Can't ask my drywall distributors, for they know nothing, never seen a manufacturers rep and the only guide is the Gypsum Constructiuon Handbook which never gives reasons.

   In New Jersey, everything here is slick paint, not like west of the Mississippi, so the curvature, ridging, etc. of the butt joint always caused me grief.  On the last job, we finished drywall in the last 3 weeks and for the first time in 2 years, some of the butts and seams ridged on me.  It's a commercial job and the exterior of the building was not sealed.  When we finished the drywall, only had propane heat, then for the next 3 weeks it was in the singel digits, the walls were cold with drafts running behind the walls.

   I had always known not to spackle under 55, just never understood the scientific reasoning behind it, so I thank you again for your explanation.

   I'm also on another construction board, and one fellow related his problems.  He first and second coated with Easy-Sand 90, the builder shut the heat off at night, and when they painted it, his screws/seams/butts popped.  He wanted to know why this happened, we all told him because of poor heat, but I was curious as to exactly what was behind it molecularly.

   What I'm doing now is using a 6 inch  scrap sheetrock, use a 1/4" of drywall glue on it and I found a  good screw that binds the butt boards to the sheetrock backer board.  When the glue dries over night - it's one solid better board.

   Anyone interested in my way of doing butt joints go to http://www.butttaper.com 

4. 
   andybuildz | Feb 02, 2003 02:05am | #14

   Zano? I have a tude? Wow...who'd a thought? Anyway.next time you cross the river and are in town give me a shout and lets bust some suds in my tipi. (latrines in the house)

   Be well with a tude..lol

                         Namaste

                                      Andy

   "Attachment is the strongest block to realization"http://CLIFFORDRENOVATIONS.COM

5. 
   jimblodgett | Feb 02, 2003 03:24am | #15

   No way I'd use MDF for what you deszcribe.  It holds a screw okay if you drill a pilot hole the EXACT right size, otherwise it's a crap shoot.

   I've always thought breaking drywall joints over headered openings was the cat's meow - shorter butts, little chance of header flexing if sized properly and dry. 

   I think you see alot of drywall cracking at corner of openings because people often cut the leg that spans the opening from one piece and butt it against a full sheet on the other side of the opening.  If the cracking was from the header flexing, we see those cracks over headers, wouldn't we?

6. 
   Zano | Feb 02, 2003 04:13am | #16

   Jim,

   I'll refer you to the attached site, it's very interesting.  A professor who specializes in wood  wrote this article.

   I quote:  "If drywall is fastened to both header and studs around an opening, the header will pull down on the drywall as it shrinks.  Fasteners in the studs resist the downward pull, placing the panel in tension, and presto! - the familiar diagonal crack.  The remedy: around openings, fasten drywall to studs only."

   This is a definite article on wood shrinkage, affect on drywall, trim, doors, etc - a must read.

   http://www.umass.edu/bmatwt/publications/articles/detailing_for_wood_shrinkage.html

7. 
   Piffin | Feb 02, 2003 05:16am | #17

   Good links Zano.

   Excellence is its own reward!