Lath and Plaster Wall = Cold….help

[delp]

Not sure there's a solution short of a medieval-era tapestry hung against the wall, but here goes the situation I'd appreciate some help thinking through:

My house is a late, 1890's solid brick end row house in Pittsburgh, PA. One side wall is a "party wall" shared with my neighbors and the other, south-west facing side wall gets all the weather coming from the west. I have an alley running along that south-west side.

This wall, from the 1st floor to the finished attic has the original lath and plaster, and the structure is two-courses of brick. The staircases runs parallel to this wall (basement to 1st, 1st to 2nd, 2nd to finished 3rd floor). I had blown in insulation blown into the "true attic" above the 3rd floor when I bought the house in 2005.

So, the issue I'm trying to address is this cold, cold wall. I'm not really willing to fur it out, insulate and then hang drywall for a couple of reasons. First, I prefer to not loose valuable real-estate on the staircase; I don't want to loose the stringer I painstakingly stripped and repainted. Second, with all its imperfections, the plaster has an historic appeal that I'd rather retain.

I'm convinced that the cold radiates or convects, or whatever, into the house. I put a thermometer at the bottom of the staircase this winter and no matter how hot the wall thermostat said the ambient air was at, the thermometer by the wall at the bottom of the stairs was never higher than 59/60*F.

One specific question I have is, can cracks in the plaster allow cold air to infiltrate into the house? There are several hairline or larger cracks in the wall, but no plaster is missing nor is there lath exposed.

Anyway, short of medieval style thick tapestries or blankets, does anyone have a ideas of how to deal with the negative effects of this cold wall?

I'm heating with an Englander 13 placed into the firebox of the living room end of a completely open 1st floor (approx 18' x 32'). I bet I'd be very content with a larger stove but I don't have the space. As it is I bet the 13 is limited by being shoved back into the old firebox, but again, not enough room to have a larger stove sticking out into the room.

Thanks for reading this overly long post!

 

[pen]

Best I can say is that it sounds like you have a good grasp on your plight, and how to deal with it. That said, you are stuck unless you do one of the things you mention above unless perhaps there is room to use a company to put spray insulation between the lath/plaster and brick?

I have one stud pocket in my house, that is in the kitchen, that was never insulated. Even though the rest of the house has next to no insulation in the walls, I can go along with the IR thermometer and read 65, all across the wall where there is only r7 or maybe r9 in the walls then hit that one pocket without insulation and read 45..... Point is, that's what happens without insulation.

If you don't want to stud that area out and insulate, if there isn't any room behind that plaster to add something, then it's just a matter of living and dealing with things, as it was.

pen

 

[delp]

Thanks for the quick reply, Pen. Yeah, it amazes me how we can't get away from the fact that everything, especially houses, are an entire "system."

I may very well concoct some sort of very tall insulated curtains to hang on that wall next winter. I bet it would make a huge difference.

Each summer I tackle one or several "house sealing" tasks, big or seemingly minor and it just leads to another "Oh, Krap!" discovery somewhere else the following winter…laughing helps…

Again, thanks for your thoughts.

 

[pen]

hehe, old homes are something.

However, if it makes you feel better, some good friends of mine who have a beautiful 2 year old house with metal roof found two leaks (by the water spots in their ceilings) this winter.

Whether it is old or new, there can be problems.

I've gotten to the point with mine, that it is at least the devil i know versus......

pen

 

[delp]

ouch…2yrs old and leaks has got to be heartbreak. I agree, old and known limitations is its own weird reward invoking odd creative efforts...

 

[dougstove]

"I may very well concoct some sort of very tall insulated curtains to hang on that wall next winter. I bet it would make a huge difference."

Depending upon humidity levels in your house, your curtain/tapestry idea could cause problems. If it creates a cold pocket against the wall, you can get condensation on the wall, and you can create a down-draft from the top to the bottom, as air cools and falls.
If the brick endwall faces an alley, might it be possible to put something on the outside, to bring the brick within the heated envelope?.

 

[EatenByLimestone]

Between the 2 courses of brick there is an air space. Foam can be injected through holes drilled in the mortar.

 

[dougstove]

Between the 2 courses of brick there is an air space. Foam can be injected through holes drilled in the mortar.

But would that mess up the weep holes and interior drainage? I think masonry walls are usually built with provision to allow water that infiltrates, to drain back out?

 

[delp]

'Morning…

DougStove:

Yes! I learned of this phenomenon this winter when I broke down and finally got thick velvet curtains (I hate curtains..I'm lucky, despite living in a city, that I look at close-by and distant trees out of every window and have great sunshine streaming in all day). Nevertheless, I have 6' tall windows that radiate the cold and the curtains really helped. But, since I'm a research addict, I paid special attention to this:

EatenByLimestone:

From all I've read, that air space between the bricks is essential to the "health" of both the bricks and the house. If the bricks can't breath the trapped moisture will wreak havoc.

Like Pen said, I have to either live with what I've got or fur out that huge wall, insulate and hang drywall. I doubt I'll ever go that route.

 

[DougA]

We paid to have insulation blown in on the in-laws house and it made a huge difference. Foam insulation, if done right, forms a moisture/vapor barrier on it's own so rain will penetrate the brick but go no further. I would assume a house that age would have to be clay brick. After the rain stops, the moisture will leave the same way it came, through the brick. They normally will drill a series of holes in the lath to pump the foam in, then you cover them up after. You do need to make sure your double brick is not loose or weak.

The only other choice is to rip the interior wall down, then foam it and drywall. If the interior walls are in bad condition, I'd do that. If you are tearing apart the wall, make sure that everyone nearby wears proper breathing equipment. The walls will likely be full of mouse and or bat excrement.

 

[EatenByLimestone]

If the 2 walls can't be considered separate systems, then we wouldn't be able to foam up behind a brick veneer. I've seen videos of insulation companies foaming through mortar joints. Maybe they are screwing the house up, but I doubt it.

 

[delp]

That's the rub…the two "walls" (exterior brick and interior lath/plaster) do act together as a single system. I may not be around to know the long term effects of blowing cellulose or foam between the wythes but if you explore/research the literature consensus points to trouble. Thing is, the brick is not simply a veneer. It is a structural element into which joists are embedded. If you diminish the ability for air circulation, you end up with rotted joists at critical structural junctures. Or, with interruption of evaporation in the freeze/thaw cycle, brick can spall and rapidly degrade.

I'll park these two links here in the hopes it may help someone using the search function in the future. The "deep dish" retrofit makes the most sense, but it is a major and likely epensive undertaking. Additionally, it completely changes the building's exterior historic character.

http://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-old-brick-buildings

http://www.buildingscience.com/documents/insights/bsi079-deep-dish-retrofits/

 

[brad wilton]

i've got the same problem but it's the whole house stone walls . i think your going to end up living with it not much you can do you can put an ever green ivy up the outside wall to cut the cold a bit but that might damage the walls also.what about installing a cat stove that would fit in the fireplace you would get longer burns and help keep heat more stable.just my 2 cents good luck

 

[woodgeek]

Apparently they have done a lot of double wythe brick walls in the UK by blowing in 3mm styrofoam beads. The better places coat the beads with acetate glue (like elmers). To get higher R-value, they get graphite loaded 'grey' beads. Apparently this avoids the issue of water transmission through the gap by the insulation, or as they say over there, 'damp issues'.

I have a decent need for this in my house...but not available commercially in North America. I am toying with the idea of doing it DIY with a shop-vac and bead-bag beads.

 

[begreen]

Is there any info about the outgassing of the styrofoam beads in the event of a fire?

 

[woodgeek]

I would assume that all foam burns and is dangerous in a fire. The beads would be a lot like beadboard (EPS) chemically. Between two brick walls is pretty fire safe. What a local code official would say, I don't know.

Apparently one issue with the beads is that the polystyrene soaks the plasticizers out of vinyl wiring jackets, making them brittle and potentially prone to cracking in the distant future.

I would trust factory blown EPS beads to outgas less nasties (without fire, over time) than any poly-urea foams done in my walls. Lower-R-value though.

On amazon you can get either 8-mm or 3mm beads by the cu ft. I was going to use the latter in some 1.5" cavities I have, drywall furred to block walls above grade, and maybe the bigger (cheaper) beads in some deeper cavities I have below grade. I figure the bigger beads are less likely to migrate through cracks.

I'm ok to rig up a blower from a shop vac, a cardboard box, a clear hose and some duct tape. Harder to figure out how to spray diluted elmers into the bead stream...maybe cheap/rented paint sprayer?

 

[DougA]

I don't understand how adding glue can possibly increase R value. If your goal is to prevent moisture issues, you are far better off simply blowing in foam. I had not considered that foam might cause rotting of joists that are hung off the double brick. If that's the case, adding glue to foam beads will have the same effect. Blown cellulose will be the better alternative IMHO.

 

[Charlotte987]

Don't know if this is possible for you, here's a stopgap measure. When we first moved into our house, (circa 1820's) the main wall in the living room was quite cold, plaster and lath with another coat of plaster on the inside. Moved in quickly and in the winter, didn't have time right away to do anything but unpack. My husband built a wall to ceiling bookcase and we placed all our books in it, it made a noticeable difference in the temperature of the room. Later we took down the bookcase to re-plaster and paint and the room became colder again. We have since reconsidered the bookshelves.

 

[Ashful]

Apparently they have done a lot of double wythe brick walls in the UK by blowing in 3mm styrofoam beads. The better places coat the beads with acetate glue (like elmers). To get higher R-value, they get graphite loaded 'grey' beads. Apparently this avoids the issue of water transmission through the gap by the insulation, or as they say over there, 'damp issues'.

I have a decent need for this in my house...but not available commercially in North America. I am toying with the idea of doing it DIY with a shop-vac and bead-bag beads.

I do believe it is available in North America, as this is exactly what I have in my framed 1894 addition. I accidentally emptied most of one stud cavity, before realizing what was there. The prior owners of my house did nothing DIY, so it was definitely a pro job.

Between the 2 courses of brick there is an air space. Foam can be injected through holes drilled in the mortar.

This is not always true. Has the OP confirmed this is indeed the method of construction, in this house?

Re: book cases, tapestries, etc. All will work, but all have the potential to permit humid interior air to contact cold exterior surfaces, and thus mold. I cringe every time I hear someone mention using curtains instead of storms to keep a house warm, in cases of old single-pane windows.

I owned one house of similar vintage to yours, in which a prior owner had installed 2x4 furring on the flat on each interior wall, 1.5" foam board between these furrings, and then 1/2" drywall. So, he lost 2" off each room (interior walls unaffected). I was living in that house 20 years after that job was completed, and saw no ill-effects, although I'd have strung up some sheeting as a vapor and air barrier behind the drywall if doing it myself. It did the trick on keeping the chill off the walls, something I'm living with on a very large scale today.

 

[woodgeek]

To clarify. The glue is PVA glue, which I think is non-biodegradable, and just keeps the beads lightly stuck together after it dries (so it doesn't pour out of crevices). The higher R-value is from mixing graphite into the EPS, which turns it grey and changes its thermal emissivity, increasing R-value. Grey EPS and Grey XPS are popular in europe, not so much over here.

Joful...hmm. I think the EPS bead thing is falling out of favor in the UK, perhaps it has already done so here.

I also can't find a guy to do 'in cavity' spray foam in my area, even if I wasn't worried about the product outgassing.

I had a pro audit and post audit work, and the whole team just threw up their hands at the cavity fill issue, esp below grade. Nada.

 

[Corey]

I would urge caution in just 'covering' the wall. I grew up in a house with minimal insulation and cold walls. In some places where furniture had 'insulated' the wall from the room, it allowed the wall to get even colder. The cold allowed water to condense out of the air, like it does on a window pane during the winter. When we moved the furniture in the spring, the wall was moldy.

For a solution on the 'simple' side, you might look at moving a bit of air to flush away the cold spots. You'll likely never warm the wall itself, but if the airspace next to it is warmed a bit, the overall effect might be what you're trying to accomplish.

 

[delp]

I feel guilty having started a conversation where, in the end, a lot of the stuff mentioned by others I feel the need to reject. I guess, like some have said, I'll just need to live with the cold wall.

I have put a fan at the top of the stairs on the second floor and it definitely helps bring the warmth from the stove up the stairs to the second floor. I don't think, like Corey says, that I'll be warming the wall at all, but it might indeed help level out the temperature.

I totally get the heads-up about not creating a moisture retaining situation with a big "tapestry" (actually, it'd just be a very tall curtain). If I do try that next winter I'd definitely keep an eye out for condensation.

As for the polystyrene beads, here's another DebbyDowner link about possible bad consequences of their use as insulation in cavity walls:

http://www.premier-heritage.co.uk/2009/08/cavity-wall-insulation-what-are-the-benefits/

 

[pen]

That's the way things go with advice.

No sweat of anyone's brow for offering it, and no obligation for you to go any specific route. At the end of the day, it's your place and you of course can do as you see fit with it based on what advice you feel comfortable with.

That said, I'm still glad the conversation took place, as it gave me a bunch of stuff to think about in future similar situations and a few ideas I'd never heard of, even though it wasn't my question.

 

[delp]

Cool-beans, Pen. Thanks.

I've screwed up a bunch of things in my life by being hasty and impatient and wanting to believe that the first thing I come across is the correct answer. I keep learning to look at situations from as many angles as possible and to learn as much along the way as I can. The last thing I want to do is make a mistake that will be hard or impossible to reverse. I'm an archivist and very interested in preservation, so I like to make sure that what I do is reversible and does not do more damage than good. Do it once, do it right…sometimes, right never comes along, so that must be okay too…cold wall = more sweaters and socks

 

[woodgeek]

I think the 'do no harm' principle is a good one.

Another article on double wythe cavity fill...

http://www.askjeff.co.uk/cavity-wall-fill/