waterproofing old stone foundation home.. i need some help!

Questions and answers relating to houses built in the 1800s and before.

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Joined: Mon Jan 08, 2007 10:20 pm

Re: waterproofing old stone foundation home

Post by bakerscottage »

I have several questions for you Captain Canuck... we want to repoint the interior of the basalt stone foundation of our 85 yr old arts and crafts bungalow. It needs the maintenance, the mortar is turning to sand. When we bought this house 6 yrs ago we were only the third family to own this house The prior 2 families who have lived here 40 &39 yrs respectively have taken very good care of this home except for the basement..it was "no-man's land" where you did the laundry, fought off spiders and stored the bikes and skates and the kid's college stuff in cardboard boxes. Now Mike has his model railroad workbench down there too and we want to reclaim the space. I agree with your advice to not disturb the soil around outside of the rock wall... Meanwhile,we first fixed the drainage around the house with rain gutters and downspouts diverting water away; foundation plantings are well away from the walls and the snow in winter does not accumulate around the foundation nor drains toward the house. We can attest that he foundation has been dry for the last 4 yrs... the project we want to eventually try is to frame off the interior of the basement , insulate, drywall and finish at least 50% of our 1,100 sq ft of basement space for clean, dry heated storage for our dismal lack of closet space on the living levels. The basement's 8ft rough ceiling height with the concrete floor is only at 7.5 ft with plumbing and other mechanical stuff in the way so the space was never finished off. Its a "walk out" basement. Over the first 80 yrs the basement suffered dampness on very rare heavy rainy springtimes from soil saturation but has never flooded nor is there regular ground water problems. The questions are: 1)after we repoint the stone will we be able to seal the interior from dampness? 2) would we be safe in finishing the interior walls so we could a)heat the space thus insulate the mainfloor above from the cold b) construct clean dry walk-in storage closets/rooms for seasonal clothes; soft line items that could otherwise be damaged by mold or dampness?. I would hate to finish walls and find the walls did not stay (nor were capable of staying) dry and thus have to be torn down due to dampness. We do not plan to convert the space into living space eg bedrooms or baths just storage and utility.

The cold main floor above is an issue too. We batt insulated between the more accessable floor joists under our heavily used office/den, which helped a lot but the rest of the basement ceiling is a mish-mash of mechanics wires and pipes which would do better being covered with a grid ceiling and the overall basement space insulated and heated. I am desparate for over-flow storage as the skimpy knee-wall closets in our large 2nd floor master bedroom are bursting. We already converted a very large original walk-in hall storage closet on the 2nd floor into a 2nd, 3/4 bath so now we have to claim the basement for storage.
CAPTAIN CANUCK wrote:Saab 900:

I too have an old house (c. 1892) with a fieldstone foundation. I recently had the good fortune to speak with an historic architect / preservationist about this very subject.

He strongly advised against digging up the soil around the outside of a stone foundation. Why? Because it would disturb the soil that has been laying against the outside of the foundation for the past century or so. That soil, compacted over the years, provides important structural support. If you attempt to dig it up and apply tar or a waterproof membrane to the outside of the stone, you may end up with a much bigger problem that water in the basement: your foundation may begin to fail.

The historic architect instead recommended the following (in order of easy/low-cost to difficult/high-cost): (1) landscaping to make sure that the soil around the outside of the foundation slopes away from the house; (2) installing a sump-pump; (3) installing gutters (to divert roof run-off as far away as possible from the soil surrounding the house); (4) installing Enkadri-and-Drain fabric (made by Colbond: http://www.colbond-usa.com) in the soil surrounding the outside of the foundation (start at the outside of the foundation wall, dig down at least 8 to 12 inches, start the fabric right up against the foundation, slope the fabric away from the foundation at the rate of a quarter-inch per foot for at least 8 feet, and wrap the fabric around the bottom and then the top of a drainage pipe that empties away from the foundation); and (5) installing a French drain inside the basement around its perimeter.

With respect to the Enkadri-and-Drain fabric, I double-checked this application with a building products architect employed by Colbond USA. He agreed that it would work.

With respect to your question about lime mortar versus Portland (non-lime) cement, the historic architect advised that the best option would indeed be to use lime mortar. But he cautioned that it is often difficult to obtain in this day-and-age and is sometimes hard to mix and use. He assured me that using Mortar Mix or Top 'n Bond (both of which contain Portland cement) would be an acceptable alternative, as they will not seriously affect the integrity of a stone foundation over a long period of time.

I hope this information will be of help. Let me know if you have any questions.

Captain Canuck

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Location: Reading - PA

Post by HB »

Do you need to insulate the basement or just heat it? If the majority of it is underground the exterior temperatures around the basement walls should never get below 50 degrees F.

I would consider just whitewashing the basement walls to give them a cleaner look that would brighten up the space and then run a dehumidifier to keeep things dry.


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repointing and sealing a stone foundation

Post by bakerscottage »

Thanks for your reply HB! We want to be able to heat the space so Mike can work comfortably at this modeler's workbench. He is an active member of the local model railroad association and works at his hobby craft on a daily basis. The laundry is also down in the basement. The logic stream is endless..If you heat a space you should first seal it from heat loss...we have to insulate. If we insulate we have to cover the walls which has the potential of trapping moisture between a porous and non-porous surface which means mold and rot. We hung a thermometer on the wall this fall and the coldest it has been so far is 52 F. when the outside temp last noc was -2 F. not too bad...however...

Is it ever recommended to paint a sealer on a poreous stone and mortar surface? Won't you trap any moisture exposure into the wall and mortar, deteriorating the very structures we just spent a fortune repairing? Or will the sealer be ok as it will only be on one side of the wall and allow the other side to breathe and dry out in the summer? Will this be ok for the lime mortar? Would the leading brand of paint-on "Dry-lok" be safe?

Back to the heating issue..I suppose we could frame and finish two interior rooms away from the exterior walls, one for his hobby room and another for the store room. If we heat only these two spaces, are we really saving anything? The rest of the house has fully insulated walls, attic spaces and storm windows. We keep the thermastat at 65 but our natural gas heating bill is still $300/mo. for 2,000 sq ft of overall living space. Anyone else listening in have suggestions? Ciao- Bakerscottage

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Post by HB »

My apologies - I should have clarified what I meant.

When I said "whitewash" I actually meant Whitewash like in Tom sawyer and Hick Finn. Not a new product like dry-lok.

Whitewash was actually just a lime and water mixture so it would be safe with your basement walls. It was often the coating of choice because it was believed to be a bit antiseptic, so it was really popular for dairy farmers in their barns and milkhouses. Turns out it was a bit antiseptic because of its alkalinity.

Good Luck.


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Joined: Wed Jan 31, 2007 7:34 pm
Location: Sullivan County,NY

basement/cellar waterproofing

Post by katey »

I've just found this site,really useful.
I have an 1840 Greek Revival farmhouse,plank-built,which intrigues all the contactors!I have found the perfect,painless solution for waterproofing fieldstone cellar walls.They inject a bentonite slurry around the outside of the walls(no excavation needed)which migrates to the walls and seals them.The company guarantees it forever.Any leaks they will re-do free of charge.I can reccommend the company.Basement Waterproofing Inc -
basementwaterproofinginc.com .They are located in Rome NY.They may know of companies in other parts of the country.I hope this will help some people.Wet basements are such a headache.It takes 4-6 weeks to seal,so we'll see.

dutchy girl
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Joined: Thu Feb 15, 2007 9:30 am
Location: Canada

waterproofing stone foundation

Post by dutchy girl »

Hi, we own an early 1900's dutch revival in Canada - right now it is -30 celcius out there. Our basement sound very similar to yours , we use it daily as a working space. I have my art studio and my husband has his office down there, cement floor, open floors above with a mish mash of wires, pipes etc. we were told NEVER to insulate the stone foundation because they are porous and if the heat from the house can't reach the stones, you will have a freeze, thaw cycle and the foundation will eventually break apart, like a flower pot left out in the winter. we have good drainage and it is quite dry. we have hot water heat, and the open rad pipes in the floor keep it quite comfortable, when very cold I use a micro furnace while working and have foam flooring squares to stand on (available at dyi stores). if your basement is damp get a dehumidifier and build a small wardrobe for your clothes, hang a dessicant in it to keep the moisture out. hope this helps.

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Re: waterproofing stone foundation

Post by DB »

dutchy girl wrote:we were told NEVER to insulate the stone foundation because they are porous and if the heat from the house can't reach the stones, you will have a freeze, thaw cycle and the foundation will eventually break apart, like a flower pot left out in the winter.
I am in the very early stages of finishing off the basement in my 1893 victorian (with stuccoed stone walls in basement). I intended to erect interior walls complete with insulation.

The quoted comment above brings the following question to mind: if the basement area is 1) currently unheated, and 2) underground, how would insulating the interior basement walls allow the stone wall to freeze? I was under the impression that radient heat from the earth kept the walls below the frost line at 50+ degress Farenheit. Any insight would be appreciated, thanks!


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Waterproofing my old foundation

Post by nonchiaro »

I own a Firehouse in Philly, built in 1893. My foundation is made up of parts from two previous firehouses on the same spot: 1850 and 1810. The foundation consists of brick, a menagerie of rock and even some porous carbon blocks (the wall and flooring for the original 1810 coal room).

This is what I've been doing....

I first scrape and clean the walls of old loose coatings and disintegrated rock/mortar. I then apply 2 -3 coats of Dry-lock water based paint. Next I apply 2-5 coats of Thoro-Seal white waterproof cement. A lot of work. A lot of time. Thereafter I apply two coats of Gunzite epoxy pool primer. So far, it is going well. I do have some hollow spots but those spots are coated in practical steel (the Gunzite) and I am not worrying greatly about them. Afterall, the basement has come such a long way. It actually smells okay.

Sweet Lew
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Location: Oak Park, IL

Re: waterproofing #

Post by Sweet Lew »

stonehousetom wrote:Hey, Good to see i can help you and I am sure they would go out to Syracuse. They are out of Rome. Basement Waterproofing Inc. 1-800439-4951.
I was amazed at what they did and would recomend them. My floor was allways wet and the water spout during storms. Ended within days. I had to do the work to sell the home. they have a lifetime transferable warantee.

Call me if you like. same area code as you.. 736-2306


Sorry..Bringing this back from the dead...Just joined the forums!"NEW" Old house (1914 farm house) owner here with very similar issues as Tom. I just called a local Waterproofing company in Chicago that does the Hydro-Clay Bentonite waterproofing. Would you be willing to share with me your cost via email? Everyone wanted to do drain tiles\sump pump and some wanted to do more. One quote was $18k to excavate and wrape the foundation in tar and plastic wrap and then add a gutter and draintile system on the outside that would drain into an interior system and then out through a sump system. After reading on here that excavating around a stone foundation is a major NO NO, I'm going with the Bentonite\drain tile solution.

One problem. The previous owners painted the interior basement walls with a water-proofing paint that is already showing effervesence. Should I attempt to remove the paint?
1908 Farm House

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Joined: Mon May 03, 2010 12:08 pm

Re: waterproofing old stone foundation home.. i need some help!

Post by breich »

I don't know if I'm right or wrong with the approach that I've taken to fixing my stone foundation, but this is what I've done from the inside. I plan on applying some of the techniques discussed by others on the outside this summer.

1. Removed the old parge coat they put on the inside wall by tapping it off with a hammer. It wasn't keeping the wall particularly dry anyway.
2. Cleans and polished the stone with a wire brush and "wire wheel" I attached to my drill.
3. Cleaned out all the joints using a tuck pointer, wire brush, and Shop-Vac. I really dug in, and actually found massive cavities in my foundation in which rodents had been storing walnuts.
4. Reapplied mortar as deep into the wall as I could to all joints and cavities.
5. Finished it with a jointer and dust broom.

Its a huge amount of work as compared to some of the methods above, but now I've got a dry and attractive stone wall where I used to have a hideous, damp mess.

I've documented the entire process and provided pictures on my blog.

http://www.98marketst.com/projects/rest ... oundation/

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