Jim Dunkel

Why do I not want to install a vapor barrier on the inside wall of my foundation? Every waterproofing person I've talked to so far who would quote the job has recommended it. If not to direct water to an internal sump, then to prevent evaporation through the walls leading to high humidity indoors. They are not recommending moisture barriers, but vapor barriers. One was BPI certified and pointed me to this article, see "news story #2"

http://www.greenbuildingadvisor.com/blogs/dept/musings/joe-lstiburek-discusses-basement-insulation-and-vapor-retarders

Of course these people are selling their products, so I take it with a grain of salt... Seems more reversible than spray foam, but virtually no insulating value so would be a possible condensing surface in summer, which should be reduced by airsealing (preventing humid air from entering) and the rest handled by dehumidification.

So, an update. We had our meeting with our home performance professional (HPP). His plan mimics much of what was supplied here by knowledgeable folks offering their opinions for free without any photos or having been in the home!

Phase 1) address basement water, add temporary dehumidification
Phase 2) air seal ceiling plane and dense pack cellulose fill wall cavities (currently empty)
Phase 3) replace oil furnace with heat pump and ventilating dehumidifier hooked to data-logging programmable thermostat

Annie and I have discussed this work, our love of this historic home, and our connection/rootedness to the area and have decided to invest in this old house and stay here for as long as we are able or forever, whichever comes first. Phase 1 and 2 should fix the mold issue, and phase 3 is optional and allows us to kick the petroleum habit and convert to solar. The one problem we face is still specifics for Phase 1. Our HPP is admittedly not an expert in this area and we need some professional opinions. He is recommending a gravel drainage plane on the floor (covered in moisture barrier and concrete) which drains to sump, then 2" of closed cell spray foam above grade and 1" closed cell spray foam below, benefits as discussed by Brian Knight earlier. For the attached crawl, moisture barrier over earthen floor, 2" of spray foam on the crawl walls. One thing I've determined is that Bill Bradbury is right to be concerned about the integrity of the masonry, everything needs to be repointed and my research suggest I should only use a hydraulic lime mortar, nothing that contains portland cement. This will be my winter project, cleaning masonry joints and repointing with HLM which can only help maintain wall stability and slow or prevent moisture ingress. In that time we will meet with various people who can assess the bedrock floor and determine drainage plane possibilities vs. exterior waterproofing options. We are undecided about foaming the walls.

Since Phase 2 is best done in warmer weather, we'll wait out the long winter with a leaky ceiling plane and empty walls, hopefully our last one. Since our walls and floors are cold, it feels cold in the house when the air is 72. The plan is to change all of that. We've been running the wood stove and humidity is down to 35% upstairs and 65% downstairs, which is down from 90% seen everywhere for a 1 week period prior to our home audit in October. The difference is the early winter we're having in NE Ohio providing cold/dry air, frozen grounds preventing moisture ingress, and a woodstove going 24/7.

We have slopey ceilings upstairs and the only real option for attic air-sealing and getting any kind of significant R value is spray foam in the 4.5 inches between rafters. Since we already installed a 50yr metal roof over everything 3 years ago, we have to do this from the inside, which means removing the ceiling entirely. Insulating/air-sealing with spray foam, and installing a new ceiling. Should be fun. We will also temporarily remove select clapboards on the exterior and dense pack the walls, then repaint the house.

Phase 3 is optional and hard to think about now, other than how do we fund it.

Bill,
I just want to say thank you for investing your time in this discussion and providing your own opinions based on what you have seen work. I understand there are pros and cons to all scenarios, Annie and I are just trying to understand the menu of choices and think critically about what will work. I've re-read your posts and it sounds like your professional recommendation is:

1) Stop all bulk water intrusion via excavating the exterior and installing drainage around the perimeter, then backfilling.
2) Build an interior

wood frame with cap break 1" away from foundation wall, rock wool insulation, Pro-Clima DB+ smart membrane and drywall coated with gypsum plaster and lime wash.

If I understand correctly, this is only recommended after step 1) is completed, otherwise bulk water intrusion would overwhelm the system. Also, since bulk water is handled by an exterior system, there are no changes required to the bedrock floor
3) Insulate and air-seal upstairs, walls via dense pack cellulose and a combination of foam and xps for the ceiling plane, followed by blown-in cellulose
4) Finish air-sealing by addressing plaster cracks and floor gaps

This approach, while expensive/disruptive/complicated to accomplish step 1, would work and lower cost of other steps may help offset some of the cost. It is an alternative to spray foam, and in your opinion, reduces risk of structural problems that could occur with allowing continued water intrusion which is managed on the interior by drainage plane routed to a sump pump.

Jim

The performance assessment/energy audit is nearly done, we are waiting on some energy modeling and then we’ll have a meeting to discuss proposed fixes.

Big Al: our secondary source of heat, a thirsty oil furnace, is in the basement, and we use it as little as possible. The wood stove keeps us warm in all but the worst cold, then they collaborate. While we wait to hear a professional opinion on fixing the place, we are not just sitting around letting things get worse! We’re doing the things that should be done regardless. We up-sized a downspout that was overwhelmed during deluges, located and cleaned out the end of the pipe where this water is routed to a small stream. I also plan to add a second downspout to this same gutter, and alter the slope to split the water between the downspouts. We’ve begun some work in the crawlspace, removing nails from the beams where they can injure anyone moving around in there and cleaning up torn-up foam insulation bits from the time the raccoons broke in and had a party. We’ve also sealed some big airleaks in the basement and crawlspace. We’re not ready to do more until we have a plan and an understanding that we will invest in this place to fix the issues. I don’t want to pile a bunch of gravel in the basement to find out we should have removed a rock ledge first, for example. While time is our enemy, we’ve been living in the house for 5 years, and others for 175 before that. We can wait a few more weeks. I know anything we would do would not be perfect, we’d be happy with a “much improved”.

Bill and Brian: Thanks for continuing the discussion on what is best and/or practical for moisture intrusion. If we had to excavate the entire exterior foundation walls and dig into the bedrock (to get the footer drains lower than the bedrock) around the house to install exterior drainage, we would have to remove/destroy two cisterns and the back porch to do it.

Bill: Do you have first-hand knowledge of situations where interior drainage below moisture retarders and walls covered in 3 inches of closed cell foam insulation have failed or caused mold issues? I would hate to go through all of the effort and expense to do something that doesn’t work. I’ve never been in a basement retrofitted this way. Would be interesting to hear from an owner who had this done 20+ years ago to see how it holds up and if it resolved moisture issues.

I appreciate the informative opinions and clarifications. I still have the below questions regarding a phased approach.

What would be the result of vapor barrier and insulation of basement walls with minimal air sealing and insulation of the upstairs walls and ceiling? I mention this not because, if we stay and tackle this project, we would not eventually do those things. But since this would require phased implementation, we'd want to do the thing that would most help the apparent mold issue first, and soon. In my mind, this would be the basement, and after taking this single step we should see a huge improvement. But I'm a rookie, here.

As I see it, providing a drainage plane below a moisture barrier and installing a capillary break under the sills, then insulating, would raise the temp of all basement interior surfaces. Maybe not to the point of the upstairs temperature, but at least raise it, decreasing likelihood of moist outside air condensing to later evaporate and keep indoor humidity high. This would also effectively air-seal the basement, but not the first or second levels. However, due to whole house stack effect, moist air that leaks in at the first or second floor is much more likely to go up, not down into the slightly cooler basement to condense. (Well, I guess this would depend on the temp of the outside air. In the winter it would sink down, but would contain far less water vapor.) Since the flooring on the first floor is single layer and much of it original, there are a lot of gaps and we expect basement air to go up into the house, especially because there are a lot of places in the basement which require air sealing. But I don't expect a lot of this to go down.

Brian and all,

I do understand air sealing as a source of water vapor in the house (though likely a minority source), and that foundation walls may be cool enough to be below dew point, offering a surface to condense on. And certainly water vapor is escaping the walls into the basement air (as evidenced by mineral encrusted surfaces of the interior rubble walls, suggesting again this has been happening for about 180 years). I'm sure I'll have this conversation with the Home Performance professional (HPP?) we've hired, but want to ask for other opinions as well. What would be the result of vapor barrier and insulation of basement walls with minimal air sealing and insulation of the upstairs walls and ceiling? I mention this not because, if we stay and tackle this project, we would not eventually do those things. But since this would require phased implementation, we'd want to do the thing that would most help the apparent mold issue first, and soon. In my mind, this would be the basement, and after taking this single step we should see a huge improvement. But I'm a rookie, here.

As I see it, providing a drainage plane below a moisture barrier and installing a capillary break under the sills, then insulating, would raise the temp of all basement interior surfaces. Maybe not to the point of the upstairs temperature, but at least raise it, decreasing likelihood of moist outside air condensing to later evaporate and keep indoor humidity high. This would also effectively air-seal the basement, but not the first or second levels. However, due to whole house stack effect, moist air that leaks in at the first or second floor is much more likely to go up, not down into the slightly cooler basement to condense. (Well, I guess this would depend on the temp of the outside air. In the winter it would sink down, but would contain far less water vapor.) Since the flooring on the first floor is single layer and much of it original, there are a lot of gaps and we expect basement air to go up into the house, especially because there are a lot of places in the basement which require air sealing. But I don't expect a lot of this to go down. This is in part because we heat primarily with wood using a first-floor wood stove. We have some convective air circulation, but we are not circulating air via a forced-air furnace unless the outside temps are below 10 degrees F or so, and that usually only happens a few times a year here.

Our HPP has already mentioned replacing our oil furnace with a heat pump that we can eventually power via solar as our back-up source of heat. We have an electric water heater now, but not a heat pump electric water heater. I'll have to look into that before ours fails and we are looking to replace. I'm learning a lot which will be useful no matter where we end up living in the end. Just thinking of the possibilities is an adventure.

Big Al,
We understand that most recommendattions will be interrelated, and we understand each step is to gain control of the system. That if one component is omitted, the system may still be out of control. It is not quite all-or-nothing, but fixing one thing without fixing the others could actually lead to new problems. Unfortunately, we don't expect to see a lot of $ savings since we heat with wood. I'm sure I'd not need to split as much wood, which would save time, but I do enjoy heating with wood and the whole process of supplying this fuel for ourselves. I can only see our hot water electricity bill dropping if the air leaks keep the basement warmer, but anything we do would be for health and comfort. If we are going to stay put, we can later invest in solar and with an up-front layout escape the electric bill and attending coal electric plant emissions. But we need to know what the whole solution looks like and costs before we can make that decision.

Brian,
I'd bet that 90% of the moisture enters the house through the basement, so sealing things up may not help moisture, but trap it in. I expect we'll learn more as the process continues. We can keep this post updated, but we haven't decided if we'll stay and fix.

Dale, I think it is either the middle of the beginning, or the beginning of the end.

Jim

Thanks Bill and Brian.

We did have a home performance professional out to our place for an initial consultation/interview. He lives in an 1835 house himself, came to building science from the insulation trade and is familiar with leading thinkers in building science. He knew about all the building science.com links provided by Brian earlier. We're currently monitoring indoor air quality in a number of locations for about a week to determine humidity, particulate, CO2, VOC and other levels throughout the house. He will be performing a full audit and developing solution packages for high, middle, and low price points explaining the benefits/value of each option and addressing the house as a system. I would not be surprised if something like the below link is on the list. The capillary break makes a lot of sense to me, just afraid of how much it might cost to lift the house to install it! I know each situation is unique, but does anyone here have ballpark estimate for this kind of project? I'm not confident I can do this myself like the gentleman at this link:

http://www.buildingscience.com/documents/insights/bsi-041-rubble-foundations

We had a blower door test and have the distinction of being the "leakiest house per square foot" that this particular professional has ever tested (over 1000 homes). The only house that beat us was 10,000 sqft. Congratulations to us? At least is should be easy to get better... Obviously we would not want to seal up the house without addressing the moisture issue.

Thanks everyone for your replies. I'm posting to clarify a few points since I co-own the house with Annie. She has done a great job describing our issues and getting this started, and thank you so much to all for your varied and informed opinions. We are new to permies, but feel like we belong here.

1. "your nearly 200 year old house did not always have this problem, so what has changed? has anyone around you been drilling(water, fracking, etc.)?" - well, we don't know that it has not always had this problem. Specifically our basement floor is sandstone bedrock with dry stacked rubble foundation, topped with barnstone and huge sill timbers upon which the house is framed. I see water coming in when it is wet outside. it comes in along the North wall between the sandstone bedrock and the first course of stones. We don't often see water actively entering the basement space during times of low precipitation or during periods where precipitation is frozen and stay on the surface. There is a shallow channel "dug" into the sandstone to guide this water diagonally to a corner of the basement which is lowest and serves as a mini catch-basin, equipped with a sump pump. The water is intentionally directed to this area, and has been for >18 years. We know the previous owners did not design it that way, and have no idea how long it has been that way. Could be since the advent of sump pumps, and before that someone may have used a bucket. That said, it does appear that our ability to control the mold is not as good as previous owners. This could be attributed to their willingness to use harsher chemicals (we mostly use vinegar and homemade non-toxic cleaners), their use of A/C during the summer which dries air out, etc. Last year was an uncharacteristically wet year in our area, and that may have led to an increase.

2. "if your water is coming from below grade (I feel that this is your problem) then you will need to address that with diversionary tactics once the source is identified. I see 3 possible sources; the stream, the pipe or groundwater." - Annie's earlier reference to a stream running under our house was in reference to the above-described water diversion to a sump pump area. We do also have a stream on the property (more like a ditch that dries in the summer and is wet otherwise) to the north of the house, maybe 150', and most of the surface water drains that way. However, the bedrock is shallow, about 5-6' below grade. I tried to pound a ground rod in for the electric fence and had to pound it diagonally to only leave 18" above grade. The bedrock appears to lean down hill from N to S under the house, as explained above. Though everything is worth considering, the water main installed at the street 2 years ago is not a likely source of this water IMHO since the water ingress has been this way for years. The cisterns are a possible source. I pumped them out and have not seen an appreciable increase in water returning to them. I know by inspection that there are no active connections to gutters or other pipes filling them. I also know by inspection the walls are cracked and water from moist soil could possibly enter. They are not completely sealed on top, but only have tiny 2" diameter openings so not much is entering during rains. We have well water, and the well is not at all far from our house, about 3' out from our back porch wall. The well is 70' deep into a sandstone aquifer. I know that not all contaminants can be seen, smelled, or tasted, but our water is pure, clean and delicious and we have noticed no changes in it over 5 years. While we are in an area of the country that is known for possible fracking, there do not appear to be symptoms of fracking groundwater problems and we know of no active fracking sites near us. We have not had earthquakes.

3. "probably the floor can have a drainage layer added, then a clay cap, then an impervious layer to seal ! This may be the same as adding a foot of earth into your basement, reducing your head height as much ! " - This is an interesting proposition. We are hoping to find the right people to come and see our unique, though not unprecedented, situation and provide a menu of solutions and costs that we can pick from. I can deal with losing one foot of headspace in the basement to solve dampness problems. We are starting with a home performance consultant as mentioned here, understanding the moisture may have multiple causes and certainly multiple ways to address it.

4. "So, as well as looking at the potential sources of ingress take a critical look at how you are using the space to see if you are adding excessive moisture through your patterns of use." This is a great point. I'm not aware of any changes which would lead to increased moisture. We did not start drying clothes or large quantities of food indoors. We will refrain from doing so.

5. "I meet lots of people who have a wet basement once. They ask me about the commercials they see for basement dry systems, and mostly, I steer them away. When you get a wet basement once, it's a drainage issue, and you prevent it with sensible use of downspouts. Landscaping and french drains if necessary. But what you're describing actually sounds like you might be a proper candidate for what they're selling. " - Do these systems require drains/gravel below the level of the foundation? If so, we might have the complication of our foundation being solid sandstone and extending greatly beyond the perimeter of our house, probably for miles in all directions! If water is entering between the sandstone bedrock and the rubble wall, how does one direct it away? Seal the wall to the bedrock? This does not seem feasible, but this is my first experience with a very wet basement. Alternatively a channel could be dug through the standstone bedrock and a french drain installed below the level of where the bedrock meets the wall, but that level of site disturbance close to the basement wall would make me nervous that the sandstone supporting the basement walls could crack and create some future structural problem.

Thanks again to all for your sense of adventure and encouragement.