Replies

1. 
   Piffin | Jul 05, 2004 12:09am | #1

   Without seein it and knowing more, I have a tendency to agree. You had these open to the elements for what - maybe three months before drying it? And then how long before getting a bonafide roof on them?

    

    

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1. 
   crownpoint | Jul 05, 2004 01:27am | #2

   Comp roof was started immediately after felting roof in, it has been about seven monthes since roof was completed.

1. 
   davidmeiland | Jul 05, 2004 02:26am | #3

   Propane heaters add a lot of moisture to the air, and we don't use them inside jobs in progress... however that isn't necessarily an issue if you're saying that some houses without heaters had the same problem. 

   It does sound like the framing is shrinking and taking the rock with it. Did you meter any of the lumber before rocking the houses? I've started carrying a moisture meter around and sticking it into lumber that's being delivered and installed. Is there anywhere you could meter the framing now? Before you start cutting and retaping it would be good to know if there's further drying to go. If there is, the moisture will be trying to get out thru the sheetrock. I've heard of people using dehumidifiers at sites to pull moisture, but have not done that myself.

   I suppose it's also possible that there's soil movement and things are settling, but that seems unlikely.

   Edited 7/4/2004 7:30 pm ET by davidmeiland

1. 
   m2akita | Jul 05, 2004 02:41am | #4

   How do the propane heaters put moisture into the air?  Never new that, is something will have to remember for the future.

   -m2akita

1. 
   TrimButcher | Jul 05, 2004 02:55am | #5

   When any hydrocarbon (propane, butane, gasoline, natural gas, etc) or alcohol is burned, the output (at 100% purity & efficiency) is carbon dioxide and water (vapour).  That's why you sometimes see water drips from a car's tailpipe - if the tailpipe is cool enough, some of the vapour condenses in the pipe.

   Eg. Propane

   C3H8 + 02 => H20 + CO2

   or a little more accurately balanced:

   C3H8 + 5O2 => 4H2O + 3CO2

   Regards,

   Tim Ruttan

   Edited 7/4/2004 7:56 pm ET by TRIMBUTCHER

2. 
   Dblchk | Jul 05, 2004 11:35am | #9

   Verry interesting...  I had heard that propane heaters produce water vapor, but have known several contractors who use kerosene heaters in the belief that they do not. Is there a difference in how much H2O is produced by each of these fuels, for the same BTU output?

   Also, where does the carbon monoxide come from in these reactions?

3. 
   TrimButcher | Jul 07, 2004 05:40pm | #11

   Regarding BTU vs. H20 produced, I could only guess that the differences are somewhat negligible. 

   Kerosene/pound = 17000 BTU (approx)

   Propane/pound   = 21591 BTU

   Octane/pound     = 20930 BTU

   So I think you might actually get more water per BTU from kerosene...but it's been a long time since I've done the necessary math to prove this.

   Carbon Monoxide (molecule = CO) is created from incomplete combustion.  No burning of a hydrocarbon is 100% efficient. Microscopic dirt particles (eg. carbon build-up in an engine) can facilitate the formation of CO.

   Carbon Monoxide is extremely deadly in tiny amounts because it is very chemically reactive. It is also odourless.   Your lungs take in O2, CO2, and CO, but your hemoglobin (blood) picks up the CO almost exclusively in place of O2.  You die from oxygen deprivation. You "turn blue" because hemoglobin without oxygen is blue.

   Regards,

   Tim Ruttan

4. 
   davidmeiland | Jul 05, 2004 02:59am | #6

   Hey, I'm a carpenter and not a physicist or chemist, but below is something I copied from another site. My neighbor, who is a scientist, once remarked to me that burning a gallon of propane releases a gallon of water... or some significant quantity like that. Maybe one of the Breaktime scientists will chime in. Anyway, here you go:

   Combustion is a chemical process that occurs when oxygen atoms excited by heat energy bond rapidly with certain fuel elements.  The most common fuel sources are hydrocarbons and related organic molecules.  These are molecules that are made up primarily from hydrogen and carbon atoms.  Methane (natural gas), gasoline, kerosene, propane, butane, methyl alcohol and ethyl alcohol are all examples of hydrocarbons and related compounds.  The hydrogen and carbon atoms in these molecules are the actual fuel in the combustion process.

   Oxygen atoms have a very strong tendency to bond with both hydrogen and carbon atoms.  In fact oxygen's potential to bond with both hydrogen and carbon is so strong that it literally rips apart the hydrocarbon molecules and forms new compounds.  When two oxygen atoms bond with a carbon atom, the result is CO2, carbon dioxide.  When one oxygen molecule bonds with two hydrogen molecules, the result is H2O, water.  Water and carbon dioxide are byproducts of the combustion of any hydrocarbon fuel.  Because the process of forming these molecules produces heat (an exothermic reaction), these gasses incandesce, which means they glow or give off light.  These glowing gasses are what make up the flame.

2. 
   Geoffrey | Jul 11, 2004 10:06pm | #12

   Hey Piffin, I would tend to agree as well. I recently worked on a project that had been left exposed for a significant time and we are just in the last month seeing puckering, even though the building was heated all winter. The project is a cathedral ceiling with a "hot" roof style(insulated cavity with no built up to vent the underside of the roof). I believe this has also contributed to the "failures" as they have been more noticeable as the temps have climbed and the humidity increases.

    Drying out a building with a propane heater requires good venting and reasonable time line, maybe as much as two weeks depending on moisture content.

                                                                 Geoff

2. 
   Zano | Jul 05, 2004 03:53am | #7

   Main two causes are wood shrinkage and humidity for drywall failure.  Since you stated it occurred in propane heated and non-heated homes, if it's not wood shrinkage nor humidity it could be that your drywall contractor is thinning the mud too much.  Just wondering if he switched from hand finishing to auto finishing?

3. 
   Frankie | Jul 05, 2004 04:16am | #8

   FWIW -

   Were all areas where the failures/ puckerings occur, done around the same time?

   Sounds like the moisture is coming from inside the walls or ceilings. You may have a improperly installed flashing detail. Is there any pattern as to where the failures are occurring? What was the weather like around roofing time?

   I don't think it's the ambient humidity, regardless of the source. For the humidity in the wood structure to cause the failure, it would have to be released quickly and must have been installed soaked.

   Second coat of compound amy have been applied prior to first coat drying. First coat may have been applied too thick.

   Just some thoughts.

   F

4. 
   Dblchk | Jul 05, 2004 11:47am | #10

   Did you get a lot of rain or have extremely high humidity during the period that the house was open to the elements?

   Do the butt joints and tapered edge joints both pucker on each wall or ceiling surface?

5. 
   dbanes | Jul 12, 2004 01:51am | #13

   You may have gotten tape that was wetted,or humidified some what...

6. 
   Zano | Jul 12, 2004 05:31am | #14

   Here are some good links and after you've read this article on humidity search for "Humidity and Drywall" for more artrciles.

   It's either wood shrinkage, humidity or too much water in the joint compound or a combo of all three.

   http://www.wconline.com/wc/cda/articleinformation/features/bnp__features__item/0,,22578,00+en-uss_01dbc.html