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Cold walls, humidity issues, frost issues with exterior doors

Cold walls, humidity issues, frost issues with exterior doors


  #1  
Old 11-10-14, 10:02 AM
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Cold walls, humidity issues, frost issues with exterior doors

We live in Saskatchewan, Canada - winters are obviously cold, commonly really cold (-30 degrees Celsius and colder). Our 850 sq. ft. 1975 built house is 2" x 4" construction bungalow so granted we don't have the best insulation possible for our climate. We have fibreglass pink insulation and the walls get quite cool during cold spells. Concrete basement construction.

Our issues:

1. The main floor southwest corner (master bedroom) of our house seems colder than the rest of the house. The laminate floor along the wall in this corner is commonly wet with condensation as is the window. The basement room directly below the master bedroom has a drywalled ceiling and the rim joists are just stuffed somewhat with fibreglass insulation. The rest of the house doesn't have a drywalled ceiling (suspended ceiling for most of it, our laundry room/furnace room has an open ceiling). I have contemplated two ways to resolve this issue:

- remove the drywall ceiling below the master bedroom and spray foam the rim joists... will this resolve our cold wall/condensation issues? I've been tempted for years to do this.
- major insulation renovation on the exterior of the house: remove stucco on exterior side of entire house, then apply 1-2" foam sheets, then vinyl siding. A big job.

2. Humidity issues - during really cold spells, our exterior storm doors frost up really bad (sometimes an 1/2" of ice and frost) to the point where they freeze shut and have to be given kick to open the door. I installed energy-efficient exterior doors and storm doors about five years ago so the doors are reasonably new. I am wondering if house humidity frost up the storm door as we open the inside exterior door, the humidity condenses and freezes to the door. Any ideas on how to rectify this frosting issue? I'm not sure about our actual humidity levels, but in winter time, Saskatchewan air is really dry because of the cold.

- would a de-humidifier be needed during a cold winter where the air is already really dry? I am wondering if our showers, dishwasher and laundry have increased the humidity to high levels that cause this frosting and condensation problem. Time for a humidity gauge...


I think all of the above is related to less than adequate insulation. Any comments or suggestions anyone?
 
  #2  
Old 11-10-14, 12:04 PM
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The moisture issues you describe are due to a continuing source of moisture. A typical home will leak its entire volume of air every 3 hours and as you stated the cold outside air is very dry. It is even dryer than the weather stations report as once it is heated to room temperatures it becomes extremely dry. A humidity gauge would help.

At 850 sq ft your house will respond quickly to added moisture. The showers, cooking, laundry, dryer vented inside, and several people add a lot of moisture. Any water problems in the basement?

The start is the humidity gauge and reviewing all sources of moisture. Something or a combination is adding a lot.

Bud
 
  #3  
Old 11-10-14, 03:17 PM
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Hi Bud! Thanks for responding!

We occasionally have a bit of water in our basement at spring thaw, but not a large amount.

Our dryer is vented to the outside, but our basement bathroom is not yet vented to the outside and I use it once every weekday and that's it (maybe this is still significant). Our main level bathroom is outside vented.

With our extremely dry winter air, you would think that any moisture from the usual sources (showers, cooking, dishwasher, etc.) would be sucked up by the dry air... we do not have a house humidifier, nor a de-humidifier. Maybe we should get a de-humidifier.

Where is a good place to pickup a humidity gauge?
 
  #4  
Old 11-10-14, 03:33 PM
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You don't need an expensive one, absolute accuracy is unnecessary. Any of the wal mart type stores or hardware stores should have them. You will want temperature at any location where you take a humidity reading. I'll add a link on relative humidity calculations.
Temperature, Dewpoint, and Relative Humidity Calculator

All bathrooms with a shower should have a delayed off switch so you can adjust the run time to where the exhaust fan continues to run for 20 minutes or so.

I assume a concrete floor in the basement. When you get your meter you will be able to test the humidity in the basement and adjust it to 70 degrees with the calculator I linked. Do the same upstairs and it will give you an indication whether the basement is the source or not.

How many people living there? Do they like to cook a lot?

A 1975 house would typically not have been built extremely tight. However, your location and climate could have prompted someone to go crazy with the plastic vapor barrier. An extremely tight home in cold country will behave just as you have described. I don't think so, but it is on the list.

Let us know when you get some readings.

Bud
 
  #5  
Old 11-10-14, 07:35 PM
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To answer your questions...

1. How many people living there? 2 adults, 2 kids
2. Do they like to cook a lot? My wife cooks regularly.
3. I assume a concrete floor in the basement. Yes, concrete.
4. "A 1975 house would typically not have been built extremely tight. However, your location and climate could have prompted someone to go crazy with the plastic vapour barrier. An extremely tight home in cold country will behave just as you have described. I don't think so, but it is on the list.": We had an government-subsidized energy audit a few years back. We put in a high-efficiency furnace, new energy efficient windows and doors. I did some air sealing in the attic with expanding foam around light boxes and air sealed the attic hole. Our energy rating is now 75 (EnerGuide).

Canada's EnerGuide ratings:

Typical Energy Efficiency Ratings
Type of House, Rating
New House build to building code standards 65-72
New house with some energy-efficiency improvements 73-79
Energy-efficient new house 80-90
House requiring little or no purchased energy 91-100

So our 1975 house rates in the "New house with some energy-efficiency improvements" category.
 
  #6  
Old 11-11-14, 05:55 AM
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Canada's rating system, figure 2, shows a similar breakdown to what I like to use, Heat Loss Distribution. The good and bad news from a 75 rating is that you know you have 2x4 walls which are not performing well, therefore something else must be scoring above average to pull that rating up. That something could be air leakage. Just speculating.

It sounds like you have the moisture load of a typical 2,000 ft˛ (state side) house, but probably have the air exchange of a well built 850 ft˛ home. If so, your humidity gauge will show us a reading above 50% and it might vary during the day with moisture production. Again, I'm speculating, but the typical remediation steps would be an exhaust fan running the 20 minutes after every shower, plus a kitchen fan when the stove is in use. Especially if you cook with gas.

Speaking of gas, it generates a huge amount of moisture when it burns. Venting for hot water and the furnace need to be check to be sure they are not venting to the inside, assuming gas.

Did CA perhaps keep a copy of that energy audit? Their breakdown would be interesting.

Bud
 
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Old 11-11-14, 11:36 AM
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1. I just bought an "Indoor Temperature and Humidity Reader" from Canadian Tire: Indoor Temperature and Humidity Reader | Canadian Tire I will move it around the house occasionally and see where the humidity is the highest and the lowest.

2. In commenting about gas appliances, we have a gas water heater and a direct-vented high efficient furnace. Our stove is electric, but the microwave/vent is not vented to the outside.

3. We do have a copy of the energy audit report, what would that reveal that I don't already know?

4. I wonder if I should give a de-humidifier a try if I discover too high of moisture levels throughout the house?
 
  #8  
Old 11-11-14, 02:22 PM
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Use that dew point calculator I posted above and take temp and RH readings in various locations. Since RH is relative to the temperature I use the calculator to determine the dew point at each location. Then, because I'm not used to using the dew point for comparison, I input each dew point and assume a 70 degree room temp. The resulting RH is easier for me to relate to. Winter RH readings without a humidifier would typically be 25%, max 30%.

If the Rh is high a dehumidifier will help, but it is a patch and expensive to run all winter. But again, it is on the list, we just don't know what it is being compared to for options.

From the report you got with that energy audit, where did they list heat loss from air leakage and ventilation?

Bud
 
  #9  
Old 11-11-14, 04:21 PM
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Using the Canadian Tire "Indoor Temperature and Humidity Reader",

Master bedroom:

humidity level is 57% min, 71% max
temperature 20.9 deg C min, 21.8 deg C max

It appears the humidity is too high... comments?

I am now measuring other parts of the house. I will post numbers ASAP.
 
  #10  
Old 11-11-14, 04:25 PM
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I will try to find the report... good question!
 
  #11  
Old 11-11-14, 06:48 PM
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Kitchen (wife just made supper, boiling water):

humidity level is 66% min, 74% max
temperature 21.1 deg C min, 22.2 deg C max
 
  #12  
Old 11-11-14, 07:46 PM
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Basement Rumpus Room (not directly below master bedroom):

humidity level is 62% min, 65% max
temperature 18.2 deg C min, 18.5 deg C max
 
  #13  
Old 11-11-14, 10:53 PM
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Yes, humidity is too high, but your min/max readings need to have each temp reading paired with each RH reading. Those numbers move in opposite directions. If I cross those numbers min with max and max with min, just for calculations purposes, I get:
Master Bedroom:
57% @ 21.8° C = DP (Dew Point) 12.9° Convert that to 21.1° C and we get RH = 59.48%
71% @ 20.9° C = DP 15.45° again @ 21.1° C we get RH = 70.15%
Kitchen:
66% @ 22.2° C = DP 15.55° converted to 21.1 the RH = 70.61%
74% @ 21.1 is already at the 21.1 thus RH = 74%
Basement:
62% @ 18.5° C = DP 11.8° converted to 21.1 the RH = 52.76%
65% @ 18.2° C = DP 11.51° converted to 21.1 the RH = 54.28%

During cold season the normal air flow through a house is into the basement, up through the house, and out the high leaks. So what we are seeing is the lower RH in the basement is picking up moisture as it moves to the upper level. Thus, the basement is not the primary source of the moisture.

Just for reference I pulled up Saskatchewan, Canada (Saskatoon) weather and currently 13° C @ RH = 77%.
Once that air enters the house and is warmed to 21.1° we get a RH = 46%. You will need to plug in your more local weather conditions, but outside winter air is usually dryer. But, if your outside air is that humid (Saskatoon had light snow) then the inside will be higher because moisture is being added.

Back to the pillow to see if I'm ready for more sleep. The things you often take for granted, like sleeping, don't always work when you get older.

Bud
 
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Old 11-12-14, 06:14 PM
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Basement room with drywalled ceiling (directly below master bedroom):

humidity level is 61% min, 68% max
temperature 15.9 deg C min, 18.7 deg C max (our basement is quite cool).
 
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Old 11-12-14, 06:18 PM
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Bud, your advice has been golden! So what do you suggest I do? I am contemplating a whole-house dehumidifier... is this a good idea?
 
  #16  
Old 11-13-14, 12:23 AM
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Moisture management wherever possible. Low flow shower heads and shorter showers (I raised 2 daughters). Exhaust fans with extended run times after showers and while cooking.

Diagnostics would involve checking the previous air leakage results and then having it tested again to see how much any improvements have tightened the house up. 0.35 ACHn is considered is considered sufficiently tight, any auditor will/should be able to determine that number or we can do it. Tighter than that and you get moisture issues, especially with cold walls.

Did you find the previous audit and the reference to heat loss from air leakage?
What is a typical outside RH reading, are you in the north, central or south?

When time permits you should address the heat loss/cold surfaces, but for now a dehumidifier will remove moisture and add heat. One of the benefits of running a dehumidifier in winter as opposed to summer is the electric used results in added heat so not wasted.

While reviewing my list, do you burn wood, thus store firewood inside? That would be a lot of moisture.

A whole house dehumidifier is an expensive long term addition. If this has been a long term problem and you expect it to continue so, then WH is probably the way to go. If you feel moisture management and some cold wall improvements and perhaps a portable dehumidifier will work, the extra money might be better used on the improvements. Hope that makes sense, only one eye open at this hour.

Sounds like you are getting a handle on the issue, very good and we are always here.

Bud
 
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Old 11-13-14, 06:06 PM
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No wood burning nor storing.

I found the energy audit binder that was given to us. In one of the government of Canada "ecoEnergy" booklets included, it states, quote: "Dehumidifiers are generally not effective in winter, since they can lower humidity levels to between 50 and 60 percent only"... any comments anyone?

Link found here: http://www.nrcan.gc.ca/energy/public...fficiency/5921
 
  #18  
Old 11-13-14, 06:31 PM
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There are different levels of performance with different dehumidifiers, but in a warm home, even in the winter, I see no problem using a dehumidifier. A cooler basement becomes more difficult but they even have dehumidifiers specifically for that location. I suspect you are going to want a better unit ans I also suspect looking at the prices, that a whole house unit would be a better unit. I would certainly ask for assurances.

You found the binder, but did it include the report with the results of the air leakage?

Bud
 
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Old 11-13-14, 08:04 PM
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I can't find the final report, unfortunately...
 
 

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