Insulating 1900 Brick Double-wythe Walls
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steves



Joined: 18 May 2005
Posts: 6

PostPosted: Wed May 18, 2005 6:28 am    Post subject: Insulating 1900 Brick Double-wythe Walls Reply with quote

I am tearing out badly deteriorated plaster in a 1900 brick house. The place was let go for YEARS before I recently purchased it. (at a great price)

The issues are:

VERY damp basement. After two weeks of dehumidifiers taking out 4+ gallons a day, the RH is still 70%. The stone and brick foundation is damp and the plaster/mud coating on the basement walls is peeling off. I am considering renting a commercial dehumidified to work faster, better at removing the moisture until I can reseal the walls. One of the largest contributors, I suspect, was a missing rain gutter that allowed the water to run back into the foundation.

I have removed a large percentage of the deteriorated plaster on the first and second floor. The third floor is a "finished" attic with drywall over plaster.

I was all set to simply frame up and put batt insulation in with drywall over it, but I read some of the segments here cautioning about condensation and trapping moisture.

The game plan, until otherwise told:

1. Fix water/moisture intrusion into basement by correcting run-off and resealing walls.
2. Frame, insulate, drywall over brick (leaving a few choice walls exposed)
3. Wide plank white pine flooring over existing sub-flooring. (should there be a vapor barrier under the 1st floor flooring?)
4. Seal all edges with caulking (I have done this in other homes which goes a LONG way to keeping out drafts, bugs, and dust!)
5. Insulate 2nd flooring ceiling VERY well, since it is not practical to do the attic and this point.

This is a HUGE project which seems to keep escalating in scope, but I want to do it once!

I'll upload some pix later tonight.
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steves



Joined: 18 May 2005
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PostPosted: Sat May 21, 2005 6:45 am    Post subject: Anyone? Reply with quote

Anyone with a comment about this plan?
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johnleeke
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Location: Portland, Maine, USA

PostPosted: Sat May 21, 2005 6:13 pm    Post subject: Reply with quote

Steve:

Your game plan is on the right track.

Forget the commercial dehumidifier. To actually do any good you will have to spend $4,000+; and, while it will lower the humudity in the cellar, that will just suck more moisture through the cellar walls and floors. What you probably (hard to tell without a moisture assessment of the entire building and grounds) want to do is isolate the cellar from the rooms above at the floor level by closing off any air movement upward along chimneys, raceways, gaps and cracks; weatherstripping the cellar door; then cross-ventilating the cellar by making the cellar windows operate easily, keeping them open when the weather is dry and warm, closing them when it is cold and damp.

...more later, I've just returned from a week-long work trip and have to catch up here in the office.

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steves



Joined: 18 May 2005
Posts: 6

PostPosted: Sun May 22, 2005 7:49 am    Post subject: Reply with quote

John,

Thanks so much for the reply...

Do you think there is much merit/benefit in putting a vapor barrier down over the existing first floor material before I install the new wide-plank flooring? Since the baseboards have all been removed, I could even run it up the walls a little.

One more thing...regarding the exposted brick walls: After I repoint them, is there something I could use to seal them to help block moisture intrusion? I have a neighbor that used Thompson Water Seal and it looks REAL good. The woodworker in me (I build early American furniture replicas) says a good coating of a thin-cut of shellac might do well and apply easily.

Thanks.
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paul



Joined: 14 Oct 2009
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Location: Cincinnati, OH

PostPosted: Wed Oct 14, 2009 11:45 am    Post subject: Reply with quote

Hi,

I have recently purchased a 3-story, brick Italianate built in 1865. It's quite livable, but yes, there is a lot of work to do!

Much of the plaster has been removed, leaving exposed brick walls (3 thick, I believe). I'm not a fan - it's pretty ugly stuff. I intend to frame them out w/2x4's and wall it up (plenty of square footage to spare).

Now, about installing insulation and the possible moisture problems that may present. What suggestions do you have? I have been reading all sorts of different things here and there, and I am no expert.

Do I have moisture problems now? Yes! It was raining for over a day the other week and many of my walls were visibly damp. I assume this is related to the exterior needing re-pointing (top of my list).

Insulate or not? What is the recommended insulation for my situation?

Thanks in advance,
Paul
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johnleeke
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PostPosted: Wed Oct 14, 2009 1:35 pm    Post subject: Reply with quote

Was your plaster directly on the interior side of brick masonry, or was it spaced out on wood firring strips and wood lath? What was the condition of the plaster and wood?

If possible I would not cover up the interior of this wall until you get the exterior pointing done and the wall has a chance to dry out. Much of the drying could be to the interior.

These walls were usually intended to do some drying to the interior, which they do even with the old lime and sand plaster in place because it is permeable to water vapor. It's usually the best bet to recreate the original interior finish system. If you simply add studs, insulation and, say, sheetrock, without solving the water problem the new work may just rot out. Anything you do to seal the interior surface of the masonry to keep the insulation and wood dry may just trap water in the masonry wall possibly causing structural damage over the long-term.

Tell us more. Can you upload pictures?

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paul



Joined: 14 Oct 2009
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Location: Cincinnati, OH

PostPosted: Wed Oct 14, 2009 7:26 pm    Post subject: Reply with quote

No chance to take any pictures, yet, but I was able to determine that the plaster was applied directly onto the brick. The western interior of the building was stripped down to bare brick some years ago, but the other sides are still plastered. The majority of the plastered walls were covered with some sort of lazy-man's wall board and the window trim is nearly flush with the wall! (That stuff is gonna go, for sure.)

Anyway, I would really like to bump the walls out to hide the electrical. The inside dimensions are roughly 15' x 55' so, there is not a lot of interior cross-wall space.

I definitely plan to repair the exterior masonry before finishing the interior walls.

I'll try to get some pictures tomorrow, but let's say the exterior will be repaired before the interior is done. Would you still recommend to recreate something close to the original finish?
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johnleeke
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PostPosted: Wed Oct 14, 2009 9:16 pm    Post subject: Reply with quote

You might stud out the walls, leave that 3.5" space empty and do wood lath and plaster over the studs. The air space would give you some insulating value, and also act as a buffer for the moisture migrating inward. The wood lath and plaster would allow some moisture migration to the interior. I would install the studs so they don't touch the masonry, and treat them with a migrating borate preservative.

This would respect the way the moisture is intended to move in this wall.

If you need more energy dollar savings get it in other ways, such as a high-efficiency heating plant.

(keep in mind these are just ideas for you to consider. What you really need to do has to be based on the actual construction, materials and conditions there. It's best to have a complete assessment done by an onsite specialist who actually knows about these older buildings.)

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Skuce



Joined: 08 Nov 2009
Posts: 188
Location: Ontario Canada

PostPosted: Thu Nov 12, 2009 12:37 pm    Post subject: Reply with quote

Water problems usually mean the original swale that was around the house in the 1800's has long been filled in.

Trees and Grass raise the ground by about 1/4" a Year. So add 100 years...ya...you get the math.
All the water now heads to the house.

"Your house is not a Boat, build a Moat"

Get the water away from the house and the water problems in the basement just go away.
Then after that you can lime plaster the walls (or do what you want) and not have to worry.

Hydraulic cements and Foam spray insulation are just like putting a cork in Hoover Dam. The water is still beating at the door...and it WILL get in.
So deal with your outside water management...THEN deal with the house.

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paul



Joined: 14 Oct 2009
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Location: Cincinnati, OH

PostPosted: Thu Nov 12, 2009 6:29 pm    Post subject: Reply with quote

I had not thought of the possibility of moisture coming up from the basement. Truth be told, it's not that bad down there -- nothing noticeable, at least. No doubt there is some moisture, though, as it's an old house built into a hill.

As far as the flora you mentioned: I don't have a single blade of grass and the near-tree-sized honeysuckle "shrubs" will soon be no more. That said, I do get your point.

More information on the condition of my walls: Some are plaster, some are bare brick. The remaining walls are sheet rock over plaster, with polystyrene sheets in between. Hm.

Still not through with the first-floor demo, but I do have masons busy replacing and re-pointing the exterior.
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