Parging a basement wall.

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

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grusvag
Posts: 7
Joined: Mon Oct 15, 2007 8:10 pm
Location: Cheltenham, PA (Philadelphia area)

Parging a basement wall.

Post by grusvag »

Hi. I'm a new user to this forum and a new homeowner of a house, that we're told, dates back to 1774.

The basement walls have the parging crumbling off at the bottom leaving a messy pile of debris on the floor. I'd like to parge, or reparge, in order to seal the walls up and try to keep the mess to a minimum. I understand I need to use a soft lime mortar mix but am wondering if anyone can tell me exactly what mixture I should use. I have very little masonry experience but am game to try on a small area at first. I bought a bag of Graymont Super Limoid Type S for Mortar, and a bag of Quikrete Portland Cement Type I/II. Will these be acceptable?

Thanks,
John.

James
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Joined: Thu Jun 23, 2005 8:36 pm
Location: Rural Eastern North Carolina

Post by James »

I am no expert on masonry, but unless I miss my guess you should probably NEVER use portland cement on an old house. Just forget that stuff exists. The lime is probably right tho. Where is HB, isn't he our resident expert on this subject?
Locust Quarter, circa 1770 Georgian Gambrel roofed cottage.

bklynwebgrrl
Posts: 41
Joined: Thu Oct 04, 2007 1:56 pm
Location: Phildelphia, PA
Contact:

no concrete!!!

Post by bklynwebgrrl »

I just did an article on this very thing::

http://www.rowhouse-magazine.com/renova ... index.html

Don't do anything until you read it as well as the documents from the parks department and the US preservation trust place which I have links too.

We have the same thing to deal with so I'm in the process of doing the research. :)
- Suzanne D.
18?? - Federal Brick Row House
Philadelphia, PA

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

Post by HB »

Skip the portland cement. It does bad things to the building because it changes the characteristics of the house's ability to shed moisture.

Although you think keeping moisture out of the basement by sealing the walls is a good idea - what you're really doing is sealing the moisture INSIDE the wall and leaving it to find other ways out, like through your wood framing, causing rot - through your siding, causing paint failure - through your plaster walls, causing paint and plaster failure.

For parging the wall I would use just the lime. Follow my instructions here

http://www.oldhouseweb.com/newBB/topic-9529.shtml

to make up the parging.

Brush as much of the loose stuff off the wall as you can with a wire brush, and then spray the wall with lime water. Don't drench it, just hit the wholee wall with a fine mist. then walk away and leave it til the next day, mist it one more time and then mix up your Mortar/parging and start spreading it on.

I would work to fill the deeper cracks first and then come back to put a finished layer over the whole thing. It's just like plastering.

Good Luck.

HB

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

Post by HB »

bklynwebgrrl

EXCELLENT article.

Thanks for spreading the word about the need for the old masonary to be vapor permeable. A very important issue that people in today's society just don't seem to understand.

Thanks for the link.

HB

grusvag
Posts: 7
Joined: Mon Oct 15, 2007 8:10 pm
Location: Cheltenham, PA (Philadelphia area)

Post by grusvag »

Thanks for all the great advice! Only other question would be: Can I paint over the newly parged wall? Or will the paint act like a seal and prevent moisture from moving in and out? Any special paint I should use? How long should I let the new parging cure or dry before painting it?

-John.

bklynwebgrrl
Posts: 41
Joined: Thu Oct 04, 2007 1:56 pm
Location: Phildelphia, PA
Contact:

Post by bklynwebgrrl »

bklynwebgrrl

EXCELLENT article.

Thanks for spreading the word about the need for the old masonary to be vapor permeable. A very important issue that people in today's society just don't seem to understand.

Thanks for the link.

HB

Thank you very much! :)
- Suzanne D.
18?? - Federal Brick Row House
Philadelphia, PA

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

Post by HB »

As far as painting the walls, after you plaster they will be quite white.

We are planning to paint our walls with milk paint.

You can learn more about that by doing a google search on the topic.

Good Luck.

HB

grusvag
Posts: 7
Joined: Mon Oct 15, 2007 8:10 pm
Location: Cheltenham, PA (Philadelphia area)

Post by grusvag »

Ok. Guess I'll wait to see what it ends up looking like and go from there.
Thanks again for all your help!

-John.

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

Post by HB »

John, I did a little more looking around and came up with this article:

http://www.buildingscienceconsulting.co ... inting.pdf

Based on this it seems that a latex primer and paint should be ok, but you'll probably want to let the wall cure for about 28 days before painting it.

Another thing that you could try is going to the local artists shop and buying some dry pigments and mixing them into your parging to get the final color you want.

For that matter, you could just dump some milk paint powder into the mix and tint it that way.

Good Luck.

HB

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