Replies

1. 
   calvin | Dec 13, 2012 09:15pm | #1

   tamorton wrote:

   I recently remodeled two bedrooms by removing carpet, putting in laminate flooring and repainting. I noticed in both bedrooms that I have a small area of condensation toward the front of the house. The house is brick with a shingled room, 2 x6 walls. In one room it is in the corner, Evidently there had been some moisture there before, because there was a small amount of mold that I cleaned off the ceiling under the crown moulding. I painted the ceiling with bulls eye after cleaning the mold, I went into the attic, didn't notice any obvious water spots or evidence of leaks on the top of the drywall. I pulled the insulation from the edge of the soffitt, thinking it was restricting airflow, but the water droplets are still there. I have full length soffitt and a ridge vent. I believe I have R-19 fiberglass batts in the attic with the paper face down. I live in southern Ohio near the Ohio River. My crawlspace is about 5 feet high, with no insulation at all (due to a flood). I also do not have any plastic on the ground in the crawlspace. Which is the likely culprit-the crawlspace or do I need more insulation in the attic? 

   I highlighted the areas I have questions about. 

   Condensation occurs when warm moist air hits a surface that's cold.  If you pulled the insulation away from that area, you probably could get condensation there. 

   If there's no air movement (heating system blocked from getting at that area) and the room is real humid (Just Painted), this could be a source.

   No evidence of water stain above?  Pretty much rules out previous yrs ice damn.

   AND, it's not been very cold (at least up here in NW Ohio to even see normal heat / cold condensation on any surface except windows.

   What is the humidity in the home?   Do you have plants in that room?  Aquarium near it?

   Is there visqueen on grade in the crawlspace?

   Any bath exhaust fans that are not working, properly vented outside or unused adjacent to the areas?

   Getting answers to these and rd's might head you in the proper direction for correcting the problem.

   I'd first check the humidity levels in those rooms.

1. 
   tamorton | Dec 14, 2012 09:46am | #3

   ceiling condensation

   In response to your questions about my post:

   Condensation occurs when warm moist air hits a surface that's cold.  If you pulled the insulation away from that area, you probably could get condensation there. This seems most likely. I am going to put the insulation back, Should I add more? I'm also afraid of restricting airflow through the soffit if I move it to far toward the eave.

   If there's no air movement (heating system blocked from getting at that area) and the room is real humid (Just Painted), this could be a source. Probably not an issue as the room is completely empty

   No evidence of water stain above?  Pretty much rules out previous yrs ice damn.

   AND, it's not been very cold (at least up here in NW Ohio to even see normal heat / cold condensation on any surface except windows. Condensation is on the window, moisture is in the corner of one room about  2 ft from the window; right above the window in the other room.

   What is the humidity in the home?   Do you have plants in that room?  Aquarium near it? Humidity level is high, about 65%, no plants or aquariums.

   Is there visqueen on grade in the crawlspace? Not sure what visqueen is, but the crawlspace is just open dirt that does stay pretty damp.

   Any bath exhaust fans that are not working, properly vented outside or unused adjacent to the area. Yes, there are bathroom exhaust fans that aren't vented properly-they go right into the attic (I plan on fixing that), but would the moisture appear first thing in the am, even if no one has used the fans?

   I ran a dehumidifier in the room for 24 hours, got about 1/4 of a 150 pint container out of it.

1. 
   DanH | Dec 14, 2012 06:28pm | #4

   The exhaust fans could be the problem.  Even if not exhausting in the near vicinity, they will blow air in all directions.  Where the air gets cold enough (which may be in the farthest corner) there will be condensation.

   And 65% humidity is pretty high -- is there any obvious reason for that?  (Though what have your outside temps been at when you noticed the condensation?  If the temp was mid 50s and raining (100%  humidity) outside then it would get to about 65% inside.)

1. 
   tamorton | Dec 14, 2012 08:03pm | #5

   I noticed the condensation beginning in the fall. temps ranged in the 40s to 60s. it doesn't seem to matter what the temp is. The drops appear even if no one has used the shower. They just show up , I notice them more in the morning, I had closed the vents in the room the past couple of days, that made it worse. I reopened them (heat pump), and the moisture is much less this evening. temps in the 50s today and clear skies. The moisture is showing up mostly on the west sie of the house.

1. 
   DanH | Dec 14, 2012 08:55pm | #6

   One thing to do is to go online and find a "dewpoint calculator".  Enter the interior temperature and % humidity and see what dewpoint corresponds to that.  If the dewpoint is higher than the temp has been in the past 24 hours then you have some sort of humidity problem in the house.  (But note that many %humidity meters are wildly inaccurate.)

   But it sounds like somehow moist air is getting into the attic.  Probably not worth pursuing further until you fix those rogue vent fans.

2. 
   calvin | Dec 15, 2012 05:06am | #8

   TA

   Is there any basement or is the whole house over crawl?

2. 
   calvin | Dec 15, 2012 05:02am | #7

   TA

   The insulation should be put back in place.  To keep from blocking the soffit air flow, make or buy the shutes made for that purpose.  You may have to damn the top plates if you use blown insulation, to keep it from falling into the soffits.  This can be done with fibreglass batts, wood or rigid foam board.

   If there's no air return in the rooms, low flow air coming from the registers may well just stay close to the floor and run right out of the door headed to the nearest return.  If you keep the doors closed this will also limit air movement as it can't really push air into that "sealed" room.

   If you turn down the heat at night, there's less air movement.  Try turning the furnace fan to "on" rather than auto (at the thermostate).  This will keep air movement on 24/7.

   Initially the higher humidity may have been the paint.  Latex paint is color in a suspension of water.  The water "dries", leaving the paint behind.  Repaint doesn't really soak in-it stays on the top of the previous coats, so the water has to go somewhere as it dries.

   65% hum is way too high-comfortable and your floors won't squeek nor will you get shocked by the carpet, but not good for limiting condensation.  The damp crawl and lack of visqueen (plastic sheeting) over the dirt hints at the real cause.  The previous mildew in the room means this problem has been long going.

   I'd work on the insulation up in the attic so you keep that ceiling as warm as you can.  Seal the dirt in the crawl with visqueen and run it up the foundation where you seal it to the foundation wall itself.  (tho just over the dirt might be beneficial.

   Correct any moisture concentrations outdoors by making sure the downspouts run to drain tile or at least are carried away from the foundation 8-10 ft.  Grade around the foundation should be tapered down and away.  Driveways, walks and patios should have fall down and away from the foundation.  A good grade of exterior caulk (NOT SILICONE) like products from Sonolast or Tremco (an Ohio Co.) should be used in the joint between these hard surfaces and the foundation especially is there's no fall and water can run to or pool against the foundation.

   Take care of the high moisture source and eliminate the cold surface.

   Best of luck.

2. 
   DanH | Dec 13, 2012 09:44pm | #2

   Where you live it doesn't get cold enough for wintertime condensation in the attic to be a problem unless there's something virtually blowing moist air into the attic, so I'd investigate any bath vent fans and the like running through the area.  Either a fan duct leaking air nearby or a through-the-wall vent below that spot with air coming up through soffit vent is a possibility.  Also a plain old plumbing vent stupidly left open there rather than running through the roof could do it.

   Or it could be wind-blown rain, through the roof edge or through the soffit vent.

   Also, given your crawlspace situation there's a vague chance that a chimney chase or such running from crawl to attic could be the problem.

3. 
   graphein | Dec 31, 2012 10:54am | #9

   Until recently, we had a dirt floor crawl, too.  And it sounds like your home, like ours, suffers (suffered, in our case) from high relative humidity.  Reducing relative humidity will reduce condensation problems.  The previous homeowner was willing to run a dehumidifier 24/7, we are not.   Basement and crawlspace moisture dries, mostly, to the interior not to the exterior because, probably even if it's a free-draining material, backfill holds moisture.  Moisture comes both through your foundation walls below grade and up through your dirt floor.  You can reduce this moisture in less and more aggressive (and costly) ways. You might take an incremental approach.  First, retard the moisture coming up through the crawl floor with a layer of plastic fully adhered to the perimeter of your crawl.  Then, re-check your relative humidity.  If it's lower, you can decide whether you can live with condensation that remains.  If not, you can then address moisture coming through your foundation walls in various ways. Note, too, that the paper facing on fiberglass batt insulation will slow the movement of water vapor. Warm, moist air moves toward cool and dry until it meets a surface sufficiently cool for condensation to occur. If you dry the air and/or warm the surface and you prevent or reduce condensation.