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Jim,
I believe it is because of the way rock is manufactured. The “rock” part is extruded wet and continuous sheets of paper are applied, the edges formed and glued. The sheets are then cut to legnth, (8′,12′,16′), as required.
I know, Iknow It’s a pain in the butt 😉 to tape.
What I do on butt seams is 1st lay in the tape, then take my 11″ curved trowel and run a “hill” about 6″ to each side of the joint. 2nd coat consists of filling the middle “valley” with the 14″ curved trowel. 3rd coat is smooth out after a light sand. Learned this from an old canadian, (the best) taper.
Something else I saw for butt seams was to lay in a piece of ply 1/2″ below flush between the nailers. End the rock on the center of the ply, screw down and fill with compound. Never tried that, but it sounds good on paper.
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Jim,
I believe it is because of the way rock is manufactured. The "rock" part is extruded wet and continuous sheets of paper are applied, the edges formed and glued. The sheets are then cut to legnth, (8',12',16'), as required.
I know, Iknow It's a pain in the butt ;-) to tape.
What I do on butt seams is 1st lay in the tape, then take my 11" curved trowel and run a "hill" about 6" to each side of the joint. 2nd coat consists of filling the middle "valley" with the 14" curved trowel. 3rd coat is smooth out after a light sand. Learned this from an old canadian, (the best) taper.
Something else I saw for butt seams was to lay in a piece of ply 1/2" below flush between the nailers. End the rock on the center of the ply, screw down and fill with compound. Never tried that, but it sounds good on paper.
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Mate...I thought they were tapered...I want to know why they're so wide and why the edges aren't tapered!!!
*Why isn't Jim Blodgett a multimillionaire with all his clever ideas?
*Tedfrd - A curved trowel? Good idea. Don't you get a noticible "mound" though?You ever hear of "butt strips"? I've never seen them used, but a friend described them to me once. I'm not sure how thick they are, maybe 1/8", you fasten them to the face of the studs adjacent to where the butt joint will be. They hold the rock out just enough there to create a small indentation to fill with mud, similar to what you describe. I hung a daylight basement remodel myself once, and was callin' around for taping bids and a well known taper asked me if I had used them, trying to get a handle on hanging quality. Seems like a good way too. - jb
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Jim,
The curve is about 3/16 over the legnth. Marshalltown or Gotlleib make them. It dous leave a slight mound, but the idea is it takes the butt "fill" and spreads it over a 26" to 30" area - easier to sand and hide.
Haven't tried the butt strips (a WHOLE lotta butts running around here), but will look for them and give them a shot.
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...'cause I spend too much time yappin' with the likes of you! ;-) - jb
*You know what would be nice? A neighborhood drywall place, where you could call up, and get custom stuff done. Like a piece 14 13/16" x 28 9/16", tapered on all four edges. I think that would be lovely. Make the building experience more enjoyable for all.
* jb,
Joseph Fusco View Image
*in the old days, around here, rock was hung vertically and there were no butt joints except on ceilings. The ceilings were blown with a heavy acoustic texture. On some jobs we still see the architects specify the sheetrock be installed vertically. This leaves a better wall finish but is a pain to tape and float and you better have your studs on layout so the edges line up properly.
*Why do we now use horizontal sheet hanging? My ceilings are nine feet high. When considering replacing beatup plaster walls with sheetrock, I was thinking of using cut ten foot pieces of sheetrock, hung with the long edge oriented vertically. Do you advise otherwise? Thanks for your advice.
*Adrian, we had that here in the States for years... but the "Peel & Stick" skim-coated plaster board company drove the local custom sheetrock company out of business. One of Jimbo's other ideas was the Velco Room... Studs, Doors, Windows, Outlets, Sconces, and wall board all done with velcro. Missus wants a new look? Rippp! Put a whole new twist on "just moving some things around."
*KAS, 54" drywall is now available to use with 9' walls. They are a little more expensive per square foot, but will save in time and materiels.
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Kas- Use 54" sheetrock for 9' ceilings. Also you can buy 9' sheetrock. In my area we can get 9,10,12,14' rock. 54" comes only in 12'.
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KAS - the problem I've seen with hanging rock vertically is that you have a long vertical joint every 4 feet (obviously Jim). Then when light shines from one end of a wall and you are at the other end, you see a row of shadow lines.
When you hang horizontally, true, you have to deal with butt joints, but they are staggered and the long joints that run horizontally don't cause the same shadow line problems because how often do you put your face against the baseboard and look up the wall?
I'm sure I made a complete mess of that explanation, but do you see what I mean? - jb
*Woke up with my face against the base board once.............didn't remember why I put it there though
*I'm glad they don't taper the ends of sheetrock. Most boards are cut to length, so you would lose your factory end on your cut off. Also it would create more work in the corners because you would have a gully to fill in. Another reason is what do you do when you have to butt up a factory edge with a non factory edge? One or two of these would look as bad as a whole room full of butt joints. I think everyone should just learn how to tape and finish or leave it to the pro's.TC
*Jim,You are way too modest. The explanation makes perfect sense to me. Seems to me you habitually end with the same disclaimer, when you habitually make sense.Rich Beckman
*Believe it or not, sheetrock has a "grain" to it, and is twice as strong along its length as width. Why? I dunno. Really -- the Taunton drywall book has a nice demonstration of this.Uhhhh, I've been hacking off the corner at the drywall butt joint and covering the joint over with mud and paper tape. Is this some tragic error? Do I really care? Do I hate drywall?
*andred d. According to Ronald Wolfe, a engineer at the Forest Products Laboratory, in Wisconsin, the tensile strength of GWB paper is four times stronger along the length of the GWB panel than across it. Because the vertical edge of the GWB is enclosed by a paper wrap it confines the gypsum core. This confinement prevents the gypsum core from breaking out as the GWB panel is stressed by the racking forces on the wall. He found that the nail loads along the bottom of the panels causes the GWB to crack and fall away from the vertically mounted panels. GeneL.
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As Joe Fusco said, gypsum board is made by pouring a slurry between the two layers of paper onto a forming line, usually between 300-600 feet long. Typically, the manufacturer pours a straight mix at the edges (tapered sides) and an air-entrained mix in the middle, that is why the tapered edges are stronger, and more dense. The continuous sheet of drywall travels down this forming line and sets up before getting to the knife. The knife cuts it into boards anywhere from 16 to 36 feet long, depending on the equipment and desired product length. It then travels through a dryer and is further processed at the end of the line. They cut the dry board into finished lengths (usually 8,10,12,16 feet long) and package it for shipping.
They can form a taper at the ends of the board, but there is very little market for it. They can also form designs into these panels, to simulate raised paneling, and coffered ceilings, and also pour cove mouldings...
I work for an Engineering company that designs the handling equipment and dryers for the gypsum board plants. We have extensive knowledge of why drywall is the way it is. BM
*>Two 4x12 sheets hung horizontally have fewer seams and less taping than three 4x8 sheets hung vertically. Also, the stronger grain direction spans the studs, instead of running parallel with them. >Tapered ends would be necessary only if the wall or ceiling is longer than the longest size available.
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Brian - "...but there is very little market for it..." I think it's safe to say that if it were available, and not cost prohibitive, folks would buy it. I would. - jb
*I didn"t look at the other posts, so forgive me if I'm repeating. The reason why sheetrock isn't tapered at the ends is because when is made it's made in one continuous 4x who knows what sheets. Then, just before being shipped it's cut into 8', 10', 12' etc.. sheets. It's cut with a machine that reminds me of an old rotary lawnmower.
*Just got thru with a house with 11 foot ceilings hung horizontally and can still see vertical marks at every stud
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Does anyone know? Thanks - jb