Old Poured Basement Wall Refinishing

[JHZR2]

We live in a 1920's house, and it has parging (screen nailed to the wall with a concrete layer spread on it, perhaps also called rough coat) on all walls in the basement. It is a beautiful job, smooth and nice rounded edges everywhere, very nice. But it is showing age in some areas.

It is just fine in most spots, but there are a few where it is coming off the wall and a few others where the concrete has fallen away. I can see efflorescence on the concrete in spots where the parting has fallen away/been removed.

The basement is not finished, so it is used as a real basement, for storage, a shop, exercise space, etc. Radon is not an issue, but we have a fairly high water table around here. The basement has a drainage system around the outer walls, and there is never standing water on the floor, we do not get leaks.

We do see a decent amount of seepage, regardless of how we manage the runoff from our roof. A combination of good sandy/loamy soil (great for vegetables), with a high water table I suppose creates just enough hydrostatic pressure to allow the walls to seep.

I don't think the basement is a candidate for finishing, because the height is just a bit too low (would necessitate a
So, it seems that the options are to remove and re-do the parging/roughcoat, or to directly apply a system of interlocking, foil faced insulating boards (thermawall I think it is called). The insulating boards is the lower cost option, though Im sure there are issues/considerations with that, as well as re-parging the walls.

Looking through places like Fine Homebuilding and other sources, it seems that insulation of basement walls is a good thing to do, and there are a few options.

But Im looking for the experience and advice of the collective here. If it were your home, how would you deal with it? Money isn't a real issue, best practice is more important to me... But it seems like the foam board option is both less expensive (by a factor of two) and more modern "best practice".

Thoughts or opinions???

Thanks!

 

[expat]

Trapping moisture in the wall is not normally a good idea. I would aim at letting the wall breath and try to keep the basement well ventilated.

Personally, I'd just patch/repair the parging and paint with an exterior latex paint.

 

[JTK]

I hear what you're saying JHZ-.

I watched a Holms on Homes episode where he applied foam board directly to poured concrete walls and floor using adhesive, calked and taped every seam, then sheeted the whole floor with plywood that was secured through the foam board with some sort of tapcon type deals. I believe then they then studded out the walls.

His foam board method was basically like dropping a giant foam liner in your basement. The only thing that scares me with that is, you never know what's going on underneath and water still has to go somewhere if it's not stopped from the outside.

I've used a product called Thoroseal on concrete block basement walls to keep water back. It's a mess to apply, but is awesome stuff.

 

[Donald]

Thoroseal - its like a rough coat itself. Will prevent weeping but not leaks.

 

[JC1]

I think the best thing would to water proof the house from the outside. Given the age of the home and possible issues, that would be a large undertaking since you'd have to excavate down to the weeping tile. Is there weeping tile on a house from the 1920's?

I'm currently finishing my basement using the owen's corning pink rigid stryofoam insulation. I had one small water leak outside and I used a black tar waterpoofing sealer to coat the exterior bricks to stop any further water/leaks.

The other option would be to install the dimpled membrane that is normally used outside, but fasten it to the interior walls first. You would need to have an interior weeping tile around the perimeter of the interior wall to capture the moisture and route that to a sump pump to discharge it outside.

Once that is setup then use a spray foam against the membrane to keep the moisture away.

This would not be cheap to do.

Do you have an idea of how much water comes in on a given month?

Regards, JC.

 

[expat]

Originally Posted By: JC1
I think the best thing would to water proof the house from the outside.


Trapping moisture 'in' the wall is a recipe for mold.

Why mess with something that has worked for 90 years?

 

[JHZR2]

There is no water that drips from the walls. Ever. No leaks.

There is an interior curtain drain that goes to a sump hole. We had this put in because many years ago the water table rose high enough that water was starting to come up from underneath. This has never happened again, and in fact, the piping that leads to the sump hole has never trickled a drop of water. The water level rises and falls in the sump hole with seasons, rain, etc., but the sump pump has NEVER come on, because the water has never risen high enough (except when I test it with a bucket of water).

The walls do weep a bit, I see that, I know it to be the case, but it is just a surface dampness. The basement does require a dehumidifier to stay below 50%, but since I work on stuff down there a lot and observe the walls, I know they dont drip, they just have some moisture.

Im not a fan of something that holds moisture underneath it, but then again, Im sure that the existing parging goes that as well... Sure, it breathes a bit, but enough? If the parging is porous, the water that weeps through cant condense and drip down into the curtain drain...

But it does sound like a recipe for mold.

That said, this says that it is now code to have basement insulation:

http://www.finehomebuilding.com/design/departments/gba-insider/retrofitting-basement-insulation.aspx

Though this is oriented towards leaks which I dont have, its coming from a PhD ASHRAE fellow who ought to know what he is talking about... ANd it talks about having an actual gap between the foam and concrete to allow moisture to condense and drip... as if it is a good thing!

http://www.finehomebuilding.com/design/qa/cure-for-a-leaky-stone-foundation.aspx

 

[Fleetmon]

I watched a home improvement show once and they were working on a basement. One of the walls was puckered inwards due to water pressure behind it....they drilled "relief" holes in the wall (water came jetting out) and they installed a fairly thin rigid plastic sheet over the walls with a very small air space between the plastic and wall. The theory was any water that got through would be directed into the floor drain field and into the sump.

They stressed repeatedly that water intrusion could only be mitigated outside the wall by excavating and re-routing the water away from the foundation. They also warned that paiting the inside wall with waterproofing would lead to excessive pressure on the wall and eventual failure if allowed to continue.

 

[JHZR2]

I dont think that there is high inward pressure. Knock on wood, my walls are fine mechanically, vertical, and I know based upon the fact that the floor has a few cracks in it that if water was sitting that high, the floor would be wet.

Im not worried about that. Ive seen holes drilled into block walls to let that water release.

Again, this is primarily if re-parging or some other newer best practice is the best way to go... The companies all want to sell non-concrete approaches, i.e. these barrier layers and whatnot, but I would love to know if the motive is selling to a price point, lack of skilled workforce, or if it really is better.

The links I provided above seem to indicate that it may well be better...

 

[Pop_Rivit]

Is the moisture on the walls from seepage or from condensation?

50% humidity is still pretty high, especially during the winter months. If the moisture is from condensation then putting up an insulation barrier would fix the problem. If it's from water actually weeping through the wall, then coating/covering the wall with anything isn't a good idea until the foundation is waterproofed.

 

[expat]

Coming from the UK and now living on Vancouver island I have seen a LOT of Damp basements in my life. Many times it has not been a problem, sometimes for over 200 years, untill someone comes along a tries to insulat.

There was a 1940's home near here, 20 years ago the municipality renovated it as a R2000 super insulated show home, tp help instruct builders on how to renovate older homes and address insulation and vapour problems.
8years ago the had to Demolish the building dur to Black Mold.

One thing I have learned. Always deal with water ingress from the outside!

 

[JHZR2]

I don't know if the moisture is from the outside or inside, but I am guessing outside. If it was condensing inside, all surfaces would seem equally damp. They aren't, it seems.

I'm going to do the condensation test to see...

Mold is scary. I don't know what's under the existing parging, perhaps I don't want to know.

Dealing from outdoors would mean complete destruction of front and rear entry stairs, driveway, patio, probably $25k worth of above ground stuff before paying $150/LF or so to dig and seal.

I'm not concerned about $3 or $6k worth of work with foam or parging, but I'm not keen on $50k worth of work if I can avoid it. At that point I may as well install solar panels and run dehumidifiers non-stop off of them.

 

[supton]

After doing some casual reading about cathedral ceilings, and how to finish basements, in regards to breathing, I've come to the conclusion: I don't want either.

Seems like this whole house sealing thing is still an on-going experiment. Still getting insulation vs breathing just right.

 

[expat]

Have you considered Chemical impregnation?

It is very common for older houses in Europe to suffer from Rising Damp this is where water from the ground is drawn 'up' into the wall by capillary attraction.
Housed built before about 1800 did not normally have a Slate or metal Damp Course. The answer is to install a chemical Damp course.

To do this you need to inject a resin (in suspension in solvent) into the wall. The normal arrangement is to drill into the wall, and install a number of bottles or funnels every foot or so. The chemicals in the bottles will leach into the wall over a week or so (it's more effective to do this at a Dry time of year) the bottles are then removed and the holes plugged.

 

[JHZR2]

Not sure how many psi the concrete is in our place, but if have to wonder how well anything would leach through.

 

[Bladecutter]

Originally Posted By: JHZR2
Not sure how many psi the concrete is in our place, but if have to wonder how well anything would leach through.


I have to admit, after listening to all your questions over time about your property, it makes me very, very happy that I'm nearing the end of having a brand new house built, with new foundation and draining technologies, instead of trying to bring an older house like yours up to current standards.

As long as the builders do their job correctly, I should have to worry a bit less about my house, which is the whole point.

Plus, I get a 4 car garage at the end of it all.

BC.

 

[Mr Nice]

I was also thinking a *newer* house would have a lot less repairs and necessary $$$$ work done upgrading _____, _____, _____ and _____.

But I also understand older houses have characteristics that new cookie cutter houses don't have.

 

[expat]

Originally Posted By: Bladecutter
Originally Posted By: JHZR2
Not sure how many psi the concrete is in our place, but if have to wonder how well anything would leach through.


I have to admit, after listening to all your questions over time about your property, it makes me very, very happy that I'm nearing the end of having a brand new house built, with new foundation and draining technologies, instead of trying to bring an older house like yours up to current standards.

As long as the builders do their job correctly, I should have to worry a bit less about my house, which is the whole point.

Plus, I get a 4 car garage at the end of it all.

BC.


I have to disagree here. I honestly have seen more catastrophic problems with houses UNDER 30 years old than with those over 80.
Most of those problems have concerned Mold, Rot or insect infestation. Cracked foundations are very common.
http://en.wikipedia.org/wiki/Leaky_condo_crisis

 

[JHZR2]

^ I agree with expat. Frankly most new homes disgust me. Sorry, dont mean to be offensive, but we can agree to disagree. Standard parts from the Home Depot moulding aisle do not make for a very interesting home, instead each one looks like every other one.

We wouldnt expect our cars to run perfect without some PM at 80+ years old, so why our homes? I have beautiful old growth pine floors, real American chestnut trim, a floorplan and layout that one wouldnt typically find (e.g. front and back stairs, stained glass windows, etc).

Problems? Not really. Ive done some upgrades, like a super high efficiency heat and hot water system, and sometimes stuff needs work. But so do many of the homes that are far newer that folks I know have. I like to learn about how to DIY, but that wouldnt be different if I had to finish or adjist a new home either.

New homes get cracks in the foundation and water leaks too. New homes need parging of the basement walls if they are going for that look, and it only lasts so long. Nothing new or different here.

Ill personally take the older homes with more character and better design attributes (IMO) to a newer one anyday.

 

[Pop_Rivit]

Originally Posted By: JHZR2
^ I agree with expat. Frankly most new homes disgust me. Sorry, dont mean to be offensive, but we can agree to disagree. Standard parts from the Home Depot moulding aisle do not make for a very interesting home, instead each one looks like every other one.



I suppose if you look at the average tract home then you might have a point. But there are plenty of high quality newer homes out there, many with plenty of character.

Back when we used to provide the capital to a team that did house flipping we got to see some things in both older homes that would simply leave me shaking my head. Occasionally a vintage house would have pine floors like yours, but they were laid directly on the joists-no sub flooring (substandard even when it was built). Unless some serious modernization has been done, homes of that vintage rarely have any insulation to speak of, the windows leak, there is asbestos, and old cast iron sewer pipes fail and leak. They have knob and tube substandard wiring, wet basements, failing plaster ceilings that were covered over with those awful little 12 X 12 acoustic ceiling tiles, tiny little garages, horrid white aluminum siding, and the laundry list goes on. To top it off you have 80 years of DIY repairs that are often marginal at best and frequently substandard themselves.

Not to mention that many houses of that vintage are in tightly packed, less than desirable inner city neighborhoods where no one in their right mind would want to own a home or raise a family. Those neighborhoods tend to attract those who can't afford anything more modern, and have to settle for a vintage house (and claim they live there because it has character).

To each his own, but both vintage and modern homes have their advantages and disadvantages. My personal preference is our almost 20 year old custom home, designed by us for us. But you are certainly welcome to your vintage home, with its wet basement/disintegrating parging issues. I'll enjoy our fully finished, waterproofed walkout basement and I can spend my time doing things other than fretting over home repairs.