Parging a basement wall.

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

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Re: Parging a basement wall.

Post by jazzman »

Can't beat the "webarchive" for looking back in time.

The dead link can be seen here: ... index.html

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Re: Parging a basement wall.

Post by patternlanguage »

Thanks Jazzman :)

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Re: Parging a basement wall.

Post by hickeyma »

Here is my feeling on the use of Lime Mortar . If you have a truly "historic" and want to keep that homes historic integrity, go for it. However, in my situation, my house (city row home) was built in 1873 in Wilmington, DE; it's certainly old but with the amount of updates done through the years it's certainly not "historic" any longer. The foundation is stone up to ground level and then transitions to brick thereafter. At some point someone did a halfa$$ job and parged over the crumbling stone walls that needed repointing more than the parging. After a lot of research and discussion I decided against the 100 percent lime mortar and opted for easier and less expensive Type S mortar. Recall, that all "mortars" do have a percentage of lime with type S being a 2 part portland cement to 1 part lime ratio, so you would still get those lime characteristics and softness with a type S and/or other types containing lime.

I've begun the tedious task of removing the parging and old mortar joints and have now completed one wall with the Type S. Another reason I went with a Type S was to create some more structural integrity to the wall as I only dug into the joints perhaps 3-4 inches max and obviously have no ability to view the integrity of the rest of the wall. Also the fieldstones used are quite strong which also eased any concerns I had with using a Type S. Lastly, I haven't had any water issues with my basement aside from usual moisture you'd expect in basement walls. My house is connected on one side to another house and an alley on the other and i'm halfway up the street on a hill so don't have any exterior drainage issues. The main reasoning behind the repointing was just the amount of chipping, dust, and in one part of the basement, the integrity of the floor joists held up by the stone basement wall. If anyone wants to compare notes let me know or if pictures would help I can try to post some. Obviously, every project is different but I think the hard stance on use of lime only mortars for old homes just turns some people off from the project that perhaps they may really just need the cheap bag from the big box store.

Also, I highly recommend Mike Haduck Masonry on Youtube on any concrete type project you have including basement/foundation walls.

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Re: Parging a basement wall.

Post by V-Man »

Hickeyma, I feel you and agree there is a pragmatic approach. However, when it comes to old, clay based bricks, parging or pointing with anything other than lime mortar is sure to cause irreversible damage and deterioration to the bricks, the mortar and ultimately the structural integrity. Sometimes the damage occurs after a few years, sometimes longer. Plenty of evidence and support for this, the English have been preaching this for a while. But putting aside what the English say, look at the picture below from my house. This is what happens to clay bricks when parged with portland based mortar; the bricks can't breathe and expel moisture.

Btw, I dig Mike Haduck's videos, but when he parges old clay brick or fieldstone that has lime mortar with portland, he's just using a short-term solution which likely will have bigger consequences down the road.
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