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Frost problem on interior wall

Wanda200's picture

Hi,


I have a small bungalow that I use as a summer place but I don't heat it during the cold winter months. (I live in Canada) I noticed the other day while I was up checking on the place that the corner of the wall on the upper landing which leads down to the basement has frost forming on it. There is no baseboard installed but that small ext. wall is insulated and it does have poly vapour barrier installed. If I installed a baseboard would that help keep out any cold air that is obvioulsy seeping in.


Is that a common problem in bungalows  that aren't heated all year round during the cold winter months.  I guess our winters are similar to New Englands winters.


wanda


 

(post #115713, reply #1 of 15)

If you don't heat it, and there's a source of humidity inside, frost will form. It may be exacerbated by a nearby air leak, or it may simply be that the corner in question isn't as well insulated as the rest of the house. (Corners often aren't well-insulated due the the extra framing required there.)

But without heat and with humidity you WILL get condensation. You can add heat, remove humidity, or just live with what sounds like a minor problem. Also be sure to move any furniture and stored items away from the exterior walls.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #115713, reply #2 of 15)

I personally wouldn't rely on baseboard to provide air sealing. I'm a bit confused ... you said it's an interior wall then said something about an exterior wall. An interior wall can get extra cold ... I've even seen frozen pipes in a building that is otherwise built well. A cold spot might be signs of e.g. a big air leak from the attic through a hole and down into the wall. For example a pipe chase or electrical hole, etc.


I would approach w/ sealing the leaks. In your case having a leak into an interior wall is not good. Even if you sealed a leak using the baseboard, you may be simply putting a bandaid on the problem and ignoring the real issue ... the cold wall cavity.


Sometimes you can run into strange air leaks that occur on interior walls that can be real major problems. Consider thinking outside the box a bit and see if you can sleuth out your real problem. The fix might be easy and very effective.

There ain't NO free lunch. Not no how, not no where!

(post #115713, reply #3 of 15)

I took Wanda to mean the interior side of an exterior wall, but with the heat off you could frost just about anywhere.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #115713, reply #6 of 15)

Hi guys,


Yes, Dan you're right I should have made myself clearer. Sorry for the confusion. It's the int. side of the ext. wall I was refering to.


Can the basement be warmer than the upper level. It's a cinderblock fondation. Not poured concrete. I guess the earth acts as an insulator.The bungalow was build back in the early 70's so it's around 33 yrs. The basement is not insulated. It's more or less a big open space. I know there is lots of moisture  in the basement. There is no dehumidifier down there. But ever since we removed the double garage door and replaced it with a regular steel door 34" wide I have noticed a difference in air quality. It feels less moist. At least there is no more water getting in. The old garage door was allowing water to seep in. For some reason whoever installed the door didn't slope the land away from the opening and the water was actually making its way into the garage beneath the garage door.


 


This summer the jointing will get done. Not sure if that will  help. We did have an evestrough installed to keep the rainwater from away from the fondation of the bungalow.


Would constructing a "trap door" just above the basement stairs help to keep the moisture from making its way upstairs?


One other ? concerning moisture. Would it do any good to prme the cinder block walls with a primer sealer. I've heard that that would prevent beads of moisture from forming on the inside wall of the basement.


Wanda


 

(post #115713, reply #8 of 15)

Based on my very vague understanding of the layout, I think what Kurt suggested is likely the case: The air is warmer in the basement because soil acts as an insulator and because, several feet down, the ground is always around 55F. The air down there is also more humid because moisture is wicked through the masonry foundation from the soil. This warm, moist air rises up the stairway and meets the cold wall. Condensation follows.

You don't say how much frost is involved. If it's only a small area (less than a square foot or so) and the frost doesn't build up any real thickness then frankly I wouldn't worry about it. But if it seems like a problem you need to control then cutting off the airflow from the basement would likely suffice.

The various masonry coatings advertised as reducing seepage do help some, but won't work miracles. And keep in mind that the moisture you're seeing may be condensation vs seeping through the walls, especially if it's high on the wall.

Do be aware that it's not a good idea to let a house freeze like this. The foundation can freeze below the footings and cause serious heaving and damage, and even without that the freezing/thawing is stressful on the structure.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #115713, reply #12 of 15)

Hi Dan,


The bungalow isn't used during the winter monts. We close it down until late spring (April) to prevent the pipes from freezing.  Usually just drain the pump and turn off the water supply . I pour plumbers anti freeze down the sink drains and toilet. The heat is completely turned off.


Now I'm not so sure that's a good idea and I am concerned about mold. Plus I'm wondering if turining off the heat will in time effect the fondation (cinder block fondation/ not a poured fondation.) Some people think it's fine turning off the heat as long as you drain the pipes so they don't burst during the cold winter months where the temp dips well below zero.


I had a mason check out the fondation last summer . He said the footings were in good condition.  If so why the black silt in the corner of the fondation? Is it normal for the bricks that the sill is resting on to be wet? Maybe that is due to condensation. I don't know. He assures me the fondation isn't going to crumble in anytime soon. This summer he wiill be back to do the jointing.  I have to wonder if that's really necessary.


Wanda


Wanda

(post #115713, reply #13 of 15)

The danger to the foundation is that the soil could freeze to a level below the footings, causing the foundation to heave. The amount of danger depends on how deep the basement is relative to the local frost level, how well sealed/insulated the structure is, and how "expansive" the soil is as it freezes.

It's not clear where the silt is that you're describing -- is it in the corner of the basement floor? If so it probably suggests that some water was flowing across the floor at some point. Of course, you can also get a silt-like accumulation due to various types of insect activity.

If the sill is resting on bricks that are resting on the cinder block, likely the bricks are there because they don't absorb moisture as much as concrete. (More modern construction uses a rubber membrane.) The cinder blocks will wick moisture up from the soil (how much depends on how low to the ground the top of the foundation is), but one would hope that not much wicks through the bricks -- the sill itself should remain dry most of the time.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #115713, reply #14 of 15)

Wanda .. not sure how long you've had this place, or where in Canada you are, but no heat spells trouble, you may just have been lucky that you have not had problems.  Since you drain all plumbing, you still need to worry about the main line from (?) freezing, the foundation heaving and basement walls cracking esp since they are block and not poured, drywall joints cracking, etc.  Yesterday, in Ottawa, the city annouced that frost is down well below 6', the last time this happened here was back in the early 90's, so in your case, that's 6' below your basement floor.  At the very least I would consider heating the basement.  You can use a trap door of sorts to help do this .. photo below ..


 


*photo didn't stick, see post below ..


Edited 1/23/2009 1:00 pm ET by wane

(post #115713, reply #15 of 15)

photo from above ..

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(post #115713, reply #9 of 15)

Hi,


that reminds me.. If I put my hand over the switch plate in the porch I can feel a flow of cool air coming through.. Is that normal? I realize you can buy those insulating pads that you put behind the switch plate to keep air out.


Last february you could actually see a thick layer of frost on teh porch wall and over the switch plate. How safe is that?


Wanda

(post #115713, reply #10 of 15)

Normal? Well, it's all too common. Not good, but common.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #115713, reply #11 of 15)

Normal? uh ... common? most definately. Do you want it? No. Could be a sign of a big problem or little problem. The switch ... on an exterior wall or interior wall? Interior wall can be a symptom of big air leakage from e.g. the attic.


Just remember ... placing the gasket on the switchplate ... that's a bandaid in a sense. You still have the air coming into the cavity. Ideally stop the air leak at the source (e.g. the hole in the top plate).

There ain't NO free lunch. Not no how, not no where!

(post #115713, reply #4 of 15)

My guess is that the basement is relatively warmer than the rest of the unheated house and if it isn't perfectly sealed, there is enough moisture that the relatively warmer and wetter air is rising up the steps and hitting the colder air in the rest of the house and the colder outside wall and condensing. Is that wall the first cold exterior wall that the air will hit coming up from the basement? In this case, you need to seal off the basement so the moisture cannot migrate to the rest of the house.

(post #115713, reply #5 of 15)

Good analysis!


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #115713, reply #7 of 15)

Hi Kurt,


yes, that is the ifirst wall that moist air coming up the basement steps touches.


Wanda