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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saab900
Posts: 1
Joined: Mon Jul 31, 2006 1:52 pm

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

Post by saab900 »

ok i am waterproofing/dampproofing my stone foundation house from the outside. there is lime based mortar which is in need of some repointing. do i use lime based mortar for pointing? if so what kind. do i also parge the exterior stone wall with lime based parging cement. i am thinking of putting new weeping tile as well as platton membrane, do i need to add a layer of tar waterproofing membrane, or will this defeat the purpose of having a breathable lime based mortar joints. p.s i am also going to insulate from outside so if any body has any usfull info on what products to use and what ill work the best in order for me to have a waterproofed home thanks.

CAPTAIN CANUCK
Posts: 1
Joined: Fri Sep 08, 2006 7:21 pm
Location: Massachusetts

Re: waterproofing old stone foundation home

Post by CAPTAIN CANUCK »

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

HB
Posts: 1645
Joined: Wed Dec 10, 2003 12:24 pm
Location: Reading - PA

Post by HB »

I agree with most of what the captain said, although using any sort of portland cement based mortar could be bad. The architect probably was mostly focused on not using a mortar that was more ridgid than the material that the foundation was mad of and that is certainly true; however, addition of even as little as 5% of portland cement to your mortar mix nullifies the moisture transmissivity of your mortar. The mortar has to allow moisture to pass freely through it so that moisture doesn't build up in you wall. A buildup of moisture in your wall can lead to deterioration of the bedding mortar, or the moisture will find it;s way out in some undesirable way like rotting a wooden framing member or making paint and plaster deteriorate higher up in the structure.

For the record, you can get Lime based mortar from a place called Virginia lime works.

Good Luck.

HB

Inspector Pete
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Joined: Wed Sep 13, 2006 5:07 pm
Location: Syracuse, New York
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Post by Inspector Pete »

As someone that has evaluated hundreds of stone foundations, the importance of exterior water control cannot be over emphasized. To add to the Preservationist suggestions above, which are great, I see good intended improvements go bad sometimes. Make sure the gutter downspouts extend far away from the building to guarantee water won't flow back to the house - check with a garden hose - six feet or more of extension is not uncommon. Make sure the grading pitch is at least 1" drop for every 12" from the house for the first five feet. Never, never water proof a foundation from the inside with a sealant paint. Once water enters the foundation, it is necessary to allow it out. Trapped water ruins mortar, rots cinderblock, and causes pressure that can ruin foundations. Once you've done the basic exterior water control, remember that old house foundations are not supposed to be waterproof - buy a 1980's raised ranch if want a dry basement :) .

Danno
Posts: 2549
Joined: Tue May 30, 2006 4:25 pm
Location: Hamilton, IL

Post by Danno »

thinking of painting a stone wall in my wife's "Wine Cellar". Want it to be breathable. does anyone have any experience with Silicate mineral paint?

http://www.elements.nb.ca/theme/buildin ... /paint.htm

looks like i should be safe with using this?????

HB
Posts: 1645
Joined: Wed Dec 10, 2003 12:24 pm
Location: Reading - PA

Post by HB »

yep, that looks like a good choice.

HB

Danno
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Joined: Tue May 30, 2006 4:25 pm
Location: Hamilton, IL

Post by Danno »

thanks for the input, HB!

stonehousetom
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Joined: Sun Oct 01, 2006 10:23 pm
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water proofing stone foundation

Post by stonehousetom »

I had a stone foundation at a home I just sold. It leaked water through the walls bad. Had one spot after a heavy rain that would shoot out like a garden hose.
I contracted a basement waterproofing co. They injected the soil with a bentonite clay/water slury. Also put an under floor darain system in. Within two days the place was bone dry. We had a 5" storm up here in NY. Still dry!

The clay filters thru the cracks to seal it. The drain system takes care of the water under the floor and pumps it out.

Inspector Pete
Posts: 186
Joined: Wed Sep 13, 2006 5:07 pm
Location: Syracuse, New York
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Post by Inspector Pete »

Danno,
Looks good from what you sent.

Stonehousetom,
Where do you live and what contractor did you use? I am always looking for good contractors in central New York. I remember well the day with 5" of rain. Plenty of basements flooded out that never before had a drop of water in them.

stonehousetom
Posts: 8
Joined: Sun Oct 01, 2006 10:23 pm
Contact:

waterproofing #

Post by stonehousetom »

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

Thanks
Tom

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