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Sorry ahead of time, lots of info I need to give to try and get the best answers, so PLEASE stick with me as I really need some solid advice as I am VERY worried my house is in need of help.
I have a low pitched (around 3/12) rambler manufactured home built in 1969 that has cathedral ceilings, looks like some paneling similar to sheetrock is attached to the bottom of the roof RAFTERS (no trusses). The kitchen area, the area above the bathroom, central hallway and the closet at the house entryway have closed in dropped (not sure if that is the proper term)ceilings that allow dead air space. Roof was supposed to be two years old when we bought the house (as-is from hack home flipper), but the roof was rotted and spongy after 12 years, mainly around the bathroom. The house flipper remodeled it and never hooked up the bathroom vent and just let it vent into the dead airspace above the bathroom and into the roof thru the hole in the paneling attached to the paneling under the rafters. Two years ago I had chose a contractor that suggested ripping off the decking and use closed cell foam insulation as it will act as a vapor barrier since the only one I had was crumpling away on the fiberglass insulation in the ceiling. They ripped off the decking and added 2×2 strips on the 2×6 rafters to get me in the r30 range after spraying and still providing an air gap at the decking. Then they added a ridge vent instead of the three turtle vents we had.
Fast forward to this last spring and a couple of issues made me concerned. First showed up last year that a few areas have the 2×2 sections slightly lifted, one more so, and that one is likely due to a vent (likely was an old range vent) that was never pulled and sealed up (did have a baffle though) and the roofers put a turtle over it. I asked what that vent was for and they said there had been a vent pipe. I had no idea what it could have been for, so I shrugged it off. Well, last year (roof one year old) called the contractor and told them about the raised section and they looked at it and didn't know why it was raised like that. They said they would fix it, but they first wanted to find out why this happened. Winter came and it was obvious there had been heat loss in this area along with the area by my front entrance. There is dropped ceiling with dead air space by my entrance, but maybe also could be a door not the best sealed leaking warm air up into the soffit?
Anyway, fast forward to about a month ago I noticed mold growing on an interior wall in my main hallway, the bathroom shares this wall, and damp to the touch on the bottom 2-8 inches in parts of that wall. I freaked out thinking it was a roof leak, called the contractor, they came out and looked things over. The one area that is obviously raised on the roof looks to be an old range vent that was never pulled out or sealed off properly, so he is thinking that is what caused the roof issue, and needed to be removed. Then he asked if the damp wall occurred before the roof and spray foam insulation, and I said no. He suggested using a dehumidifier for the time being. I used vinegar to clean up the mold and put the dehumidifier in the hall for two days, then moved it into the bedroom across the hall and set it to 60% and did not have any damp feeling to the wall in the hall for a couple of weeks. The wall opposite in the hall had no damp feel to it, and that wall is shared by a bedroom with no dropped ceiling with dead air space, but the damp wall is the side shared with the bathroom with the dead air space. Funny thing is my bedroom shares a wall with the bathroom, and in my closet ceiling there is open space that is the dead air space above the bathroom, in other words the wall of my closet does not go all the way up to the cathedral ceiling , it is open from the top of the framing of the false ceiling up to the cathederal ceiling. I don’t have a closet door so it is always open, but mind you the opening to the dead air space is not much more than maybe 12″ tall at the edge of the closet opening.
The contractor told me they want to spray insulation foam in the dead air spaces and any of the dead air spaces that they add insulation to, he will need to cut out the foam at the ridge to allow the heat to vent through the ridge vent. All the vaulted ceilings will stay as they are. It’s just the dead air spaces they need to insulate and vent out at the peak.
My concern is if they fill the area with foam, will that not create two vapor barriers if it is not completely filled up? Would fiberglass be better? My house is full electric so we do not have a furnace, my wife admitted she only turns on the bathroom fan when it stinks in there (her bathroom is upstairs, mine is in the basement, and more on that later), but she doesn't take showers, only baths, and yes I know it still creates moisture, and she has now changed when she turns on the fan.
Well, with all this humid weather the last week the bottom of the walls are damp again, and now in the wall that seperates the kitchen from the living room, and that wall has a large opening. We are only running window air units in our two bedrooms. The condensation can't be running down from the dropped ceiling because that large opening would make it run to the ends, it is damp right under where the large opening is. Wife cooked in there, but put a box fan blowing out of our french door to try and help push out moisture. I moved the dehumidifier to the living room yesterday afternoon set at 50% (sucks because it puts off heat....). We have a VENTLESS hood above the electric range, and am looking into hiring someone to add a vented hood in its place since the wall it sits on is an exterior wall hope it will not be too costly. Yesterday I looked at our weather gauges when I did that (not sure how accurate), it was warm in there, about 86 degrees and 72 for humidity (assuming that is relative humidity?).
Then it got me thinking, our basement is pretty cool, maybe the heat difference from the basement to the upstairs is causing the wet lower walls? Also, my bathroom down stairs has a fan that is not hooked up to a vent (POS house flipper did not run one, just hid it), but I have a dehumidifier run year round just outside of my bathroom.
We did have a lot of moisture on our two bedroom windows that do not have a baseboard heater under them, and even worse that we have curtains covering them, had frost on them and when warm it turned into condensation. The windows are horizontal sliders that we put window air into and looks like the windows are starting to leak causing the frost on the storm windows, so looking to replace those with double hung windows instead, but never realized that heavy of moisture on them before.
We are now getting quotes to install a ductless mini-split heat pump with three heads thinking maybe it will help lower the humidity level in the summer, but don't think it will help in the winter (but MIGHT lower cost to heat over using electric baseboard heaters) and the first quote was 12K for a hyper mitsubishi unit (price is not worth it if it only helps in the summer though.....)
SOOOOOOOO, down the the main questions:
1. what are acceptable humidity levels in a house that does not run conditioned air thru most of it, including how much during winter? First 5-10 years (guesstimate only) the winter caused static electricity, but we have not had that dry in the winter for a about 6-10 ten or so years (been in house about 14 years).
2. I know I need to get someone to run a vent outside for the basement bathroom fan, and adding a vented hood for the kitchen, any good contractors you have delt with in the twin cities?
3. I know our problem has probably been with us the whole time, but now that we have a real vapor barrier in the ceiling from the closed cell foam, the moisture is not escaping thru it (and not rotting our roof deck), so how do I go about this to correct the issues without just throwing money at it, and hiring people that truly know know do solve this if I can not on my own?
4. Does what the contractor plans on doing sound like a sound choice? Is the dead air space likely causing the damp wall? Has anyone seen anything like this before? Also any idea why a few of the firred out 2×2’s on the roof would of lifted? They said they could use fiberglass in the dead air space and to cut out the foam at the ridge a good idea instead? They are trying to work with me on a good solution, and both want a good result, but I am sure I want it more, I need my house to be sound as I plan on living there till I die if it does not fall apart to the point of not being able to afford the repairs, or the repairs make it not cost effective.
5. What are the best methods to try and find out where the humidity is originating from?
6. Would a ductless mini-split truly help year round, or just mask the problem more?
7. would a 30 gallon fish tank make that much of a difference in humidity level, can't be can it? We have had one for five years or so in the living room.
THANK YOU SO MUCH FOR READING THROUGH ALL THAT! I know it is a lot, but I am losing sleep over this issue.
Last week has been pretty humid, so I have had to keep the house closed up, even though I only have window a/c in two closed bedrooms, causing temps to stay about 82-85 in the house during the night and daytime using a box fan blowing the cooler air from the basement (basement has two dehumidifiers down there). I tried to get more ventilation going by placing window fans in a separate bedroom, and then in the living room when it was a cooler 74 degree temp in the morning, but the dew point was about 70 causing a ton of moisture in the house and had to close it up again. Seems when ever the relative humidity is lower than it is in the house, the temperature is higher with a dew point around 66-70 which feels pretty sticky. With the house at 82-85 degrees I am running between 61-65 for relative humidity according to a cheap weather set (have a hygrometer coming in the next week).
Like right now it is only 76 degree outside, about 8 degrees cooler than inside my house, but the humidity is 77% with 68 dew point. How the heck do others in the twin cities without a/c keep there inside humidity levels to recomended of under 60%?
Ps
my walls feel dry now, but that might be from the basement fan pushing air around instead of the still air the house has had for a while.
General Advice:
How many hours per day do you keep your system running?
A lot of smart people use set back controls and the equipment doesn't run enough.
Other systems don't run enough per cycle (most don't).
Some systems are shot.
Get a quality thermometer and measure the air temp at AC registers.
Closest to and farthest from the unit; supply and return.
Different times of the day.
Sorry, it stays cool in the a/c rooms, trying to keep the humidity levels down thru the rest of the house since I had mold growing on the lower section of the hallway wall, too much humidity and no real ventilation other than a bedroom fan pumping in humid air
Humidity indoors should be below 50%, I prefer closer to 40%. Buy 70 pint dehumidifier, costs ~$250 in offer.
It makes room bit warmer but reduces humidity
Similar problems here. I got the Blu-Dri dehumidifier for our basement that is on wheels for the interim until I can get labor to fix our moisture and leak problems here. Easier to move around, and pumps water vertically up and out into drain. It is huge, and it's blue - so need storage spot off season. I also got 20" circulation fans placed at base of stairs in basement to send the cooler air up the stairs. You need a dehumidifier both levels - bigger one in basement. We keep another dehumidifier machine in laundry room. I try to keep humidity level at about 40%.
We have the older version of ductless mini-split A/C system - high velocity version with tubes running through closets and little holes punched out all over house; includes the main floor, and a 8' ceiling basement that goes underground with 42" foundation for Michigan frost line, no traditional vents (just holes), but does feature traditional intake vents.
Difficult to find any available contractors willing to work on pre-existing homes here where we live. Absolutely no one in our area does insulation exclusively, and the A/C installers require the insulation removed so they can work on the attic a/c units first. We are due for an A/C replacement system - several bids $30K each - if we can remove our own insulation. Nope. I am not doing that. So we are left awaiting full death of the current system that includes two units in attics, and two outdoor compressor units. The coils will freeze up on the attic units if run for 8 hours straight.
But we are focused more on the heating issue as we have no heat right now, not good in Michigan. Building boom of new housing has booked the pros up. We have water coming up through tiles in basement, boiler runoff filling buckets full of water, and half bath that floods each time it rains. Just had a hydronic pipe burst few weeks ago - underground or in slab, not sure which - resulting in $1900 water bill. Trying to find a contractor to rebuild our heating system that has now fully failed and has been costing us $10k per year in service calls to keep it running as it was. My husband keeps getting talked into fixing instead of replacing with a warranty on a new system. I say replace the whole damn system. But again impossible to find copper-fin hydronic loop installers. Big mess here.
You do have a sump pump, that works - right? If not, get one installed if possible. Also, try to find a waterproofing specialist. I am also looking for that too.
Last edited by PacificaViews; 07-11-2020 at 07:51 AM..
Last week has been pretty humid, so I have had to keep the house closed up, even though I only have window a/c in two closed bedrooms, causing temps to stay about 82-85 in the house during the night and daytime using a box fan blowing the cooler air from the basement (basement has two dehumidifiers down there). I tried to get more ventilation going by placing window fans in a separate bedroom, and then in the living room when it was a cooler 74 degree temp in the morning, but the dew point was about 70 causing a ton of moisture in the house and had to close it up again. Seems when ever the relative humidity is lower than it is in the house, the temperature is higher with a dew point around 66-70 which feels pretty sticky. With the house at 82-85 degrees I am running between 61-65 for relative humidity according to a cheap weather set (have a hygrometer coming in the next week).
Like right now it is only 76 degree outside, about 8 degrees cooler than inside my house, but the humidity is 77% with 68 dew point. How the heck do others in the twin cities without a/c keep there inside humidity levels to recomended of under 60%?
Ps
my walls feel dry now, but that might be from the basement fan pushing air around instead of the still air the house has had for a while.
Since you have a basement, I would definitely install a good quality dehumidifier there. personally I would recommend a Santa Fe dehumidifier from Sylvane. you can order them online and the shipping is free. They are industrial strength quality and will dehumidify the entire basement. You will need to have a drain or sump hole for the water to drain into (and it sounds like you need a sump pump anyway). I've run 2 in a crawlspace and have one unit in my basement now. I keep the basement at 40% humidity or less; it really makes a difference in keeping any damp loving insects out and has dried out any existing damp in the joists. I would bet that a basement dehumidifier would help eliminate the mold on the lower part of your walls.
Humidity indoors should be below 50%, I prefer closer to 40%.
Whether humidity should be below X% or not aside...
the starting T&H numbers will usually dictate what the result T&H numbers CAN be.
Start at 83% humidity and you're doing well to get below 55%
Start at 66% (like it is in Austin now) and a mid 40's% result might even be expected.
edit to add: Running a second machine (like a dehumidifier) in addition to the central AC...
is mostly going to just increase the electric bills. otoh hanging a few DampRid bags WILL help.
Last edited by MrRational; 07-11-2020 at 08:49 AM..
Since you have a basement, I would definitely install a good quality dehumidifier there. personally I would recommend a Santa Fe dehumidifier from Sylvane. you can order them online and the shipping is free. They are industrial strength quality and will dehumidify the entire basement. You will need to have a drain or sump hole for the water to drain into (and it sounds like you need a sump pump anyway). I've run 2 in a crawlspace and have one unit in my basement now. I keep the basement at 40% humidity or less; it really makes a difference in keeping any damp loving insects out and has dried out any existing damp in the joists. I would bet that a basement dehumidifier would help eliminate the mold on the lower part of your walls.
Depending on the size of OP’s basement this might be the best option, or overkill. Before spending $1200+ on a Sylvane I’d spend 15% of that on a 70 pint portable. Costco sells one for around $180 that includes a discharge pump. If it works, great. If it doesn’t, or if it breaks, take it back.
Depending on the size of OP’s basement this might be the best option, or overkill. Before spending $1200+ on a Sylvane I’d spend 15% of that on a 70 pint portable. Costco sells one for around $180 that includes a discharge pump. If it works, great. If it doesn’t, or if it breaks, take it back.
Sure, he can always try that for a start. At this point any dehumidification would be a help. My recommendation was based on the severity of his problem which sounds like it exceeds the capacity of a 70 pint portable IMHO.
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