I am having a problem with several GWB Cathedral Ceilings installed in Southern New York. The tape is separating from the GWB at the angled joints in the ceiling within the first year after construction. The ceilings are properly vented and a vapor barrier is installed. I am not sure if the problem is a result of the roof settling, condensation, or a poor taping job (the seams are not separating at any other locations). Does anyone have experience with similar problems? Should a special type of tape of joint compound be used at cathedral ceilings?
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If they used the Strait-Flex tapes without the additive called "Super-Bond", then they will peal. "Super-Bond" is a glue that is mixed in with the all purpose mud. This happens because the compound cannot adhere nor penetrate into the tape.
If they used regular paper tape with all purpose mud - it should not happen.
If they used the "Ultra-Flex" tape with an all purpose joint compound then it should not happen, but in all cases if they used light compound then they all may peal.
Zano,
Geez, I feel like puking. Just tried Straight-Flex for the first time on cathedral ceilings in my dyi house. One room finished, another about ready to paint.
I threw the directions away but don't recall any mention of glue...guess I could have missed it. Just checked the web site and there's no mention of glue in their installation hints, either. What's up with that?
I thought it was tougher to bed than regular paper tape but it sure makes nice straight lines. Guess it doesn't matter it it's really going to peel off...
Todd
Did they block between each truss at the peak of the cathedral on each side? We used to see this every year when the temp. dropped and the bottom chord of the truss lifted due to the temp. When we started cross blocking at the peak, the problem went away.
"The tape is separating from the GWB at the angled joints in the ceiling within the first year after construction. "
When you say the "angled joints, do you mean at the peak of the cathedral, or where the walls meet the sloped ceilings, or both?
"The ceilings are properly vented..."
What's "proper" can be pretty subjective. What kind of venting does it have?
I'm not 40-something. I'm $39.95, plus shipping and handling.
The ceilings are hip ceilings with a flat tray at ten feet and are framed with 2x10 rafters and no trusses. The tape is separating at the hip and where the angle meets the flat. It is not separting at the wall / ceiling intersection.
In terms of venting there is a continuous louvered 2" soffit vent and the attic has a continuous ridge vent. Rafter-Mates are provided above the insulation and the rafters are drilled at the hip to allow some air movement around the hip.
You are going to have to climb up there and see. Look down the joint and see if its had solid blocking. Then tear the tape off and look to see how they taped it and if there is a bond of mud. If the mud soft or hard ? Then lets talk here again . The condition of the mud underneath can tell several different things.
Tim Mooney
I checked the taping more closely. The tape at the off-angles is not conventional paper. It looks like Strait-Flex or something similar. The mud underneath is currently hard and dry.
You didnt mention if there was a straight plane by eyesight. That was to judge if it had pulled loose .
At any rate you can check for solid blocking which solves it in the new construction phase , but you are in repair mode I assume. Durabond setting compound will rerair it and offer the bonding needed to set it back. It comes in a powder and usually 90 minute is on the shelf. Thats the quick fix, but not the best.
The best fix is to nail a 2x6 down the middle and build a false beam . This will take care of any movement problems from showing. I normally mount wiring and a light fan off of that to take moisture off that peak and other reasons. The high point of cathedrals need added air movement even if there is not a problem .
The final approach is that the beam and light fan will compliment the problem as a fix normally with out tearing up that ceiling. If the ceiling is textured , its the top choice. IMO.
Tim Mooney
How was the ceiling finished? Primed and painted?
You get out of life what you put into it......minus taxes.
Marv
Yes, the finish is Primed and Painted.
Having a vested interest cause I used straight flex without the additive, I called the tech department. They said that they changed the product a while ago and added a coating to the backside of the tape that eliminates the need for glue. Some people still use it but it's not necessary for a lasting bond. FWIW...
Todd
I posted my first post too early this morning and then went to work then I thought it could be caused because of no back blocking - glad someone mentioned it.
If you used Strait-Flex, even the new kind, I don't think it's strong enough to withstand the wood movement. The vinyl Strait-Flex that someone mentioned is now your best bet, or you could use the No-Coat "Ultra-Flex" but be sure to keep the mud on the edges of the tape. As far as a glue on the new Strait-Flex tapes; maybe just maybe, I think mud on a light adhesive will destroy the adhesive. The problem with the Strait-Flex tapes is that the mud is totally underneath the tape even in the tip of the angle, while on the Strait-Flex vinyl and the Ultra-Flex, the mud is on the edges and allows the tip (center) to move to compensate for the wood movement.
Anyways, Strait-Flex has a new metal that bends to any angle that you apply to the wood before the rock goes on - it's a backer so you can screw the rock to it.
Thanks for the good advice. I'll make a change as suggested, got a couple more cathedral rooms to do.
Todd
Now you're blaming Bush for your ceiling problems???? <G>
If you find that you need to replace the product, I suggest looking into a product called Magic Corner by Trim-Tex. It is made for use in off-angle situations, and its primary feature is that it has a flexible vinyl hinge that allows movement in the two ceiling planes without cracking. I have used it on cathedral ceilings for about 5 years without any signs of cracking. I think that some movement in cathedral ceilings is inevitable, especially in the first year after construction as the lumber dries and shrinks. Good luck with your problem.
Edited 12/3/2003 3:59:44 PM ET by Nick Pitz