# Lath and Plaster Wall = Cold….help



## delp (Mar 21, 2015)

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!


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## pen (Mar 21, 2015)

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


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## delp (Mar 21, 2015)

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.


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## pen (Mar 21, 2015)

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


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## delp (Mar 21, 2015)

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...


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## dougstove (Mar 21, 2015)

"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?.


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## EatenByLimestone (Mar 22, 2015)

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


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## dougstove (Mar 22, 2015)

EatenByLimestone said:


> 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?


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## delp (Mar 22, 2015)

'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.


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## DougA (Mar 22, 2015)

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.


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## EatenByLimestone (Mar 22, 2015)

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.


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## delp (Mar 22, 2015)

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/


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## brad wilton (Mar 22, 2015)

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


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## woodgeek (Mar 22, 2015)

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.


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## begreen (Mar 23, 2015)

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


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## woodgeek (Mar 23, 2015)

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?


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## DougA (Mar 23, 2015)

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.


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## Charlotte987 (Mar 23, 2015)

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.


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## Ashful (Mar 23, 2015)

woodgeek said:


> 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.



EatenByLimestone said:


> 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.


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## woodgeek (Mar 23, 2015)

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.


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## Corey (Mar 23, 2015)

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.


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## delp (Mar 24, 2015)

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/


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## pen (Mar 24, 2015)

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.


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## delp (Mar 24, 2015)

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


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## woodgeek (Mar 24, 2015)

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/


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## Charlotte987 (Mar 24, 2015)

I've noticed that people have mentioned problems with mold on walls after some areas of their cold walls were covered on the inside with curtains, or furniture or whatever.  The bookcases that we put up worked well, no mold on the books or on the walls. The house is covered in exterior painted asbestos tile over a spruce wood surface on the two upper stories, with plaster and lathe and more than a foot of plaster on the inside, it must be this particular configuration that's prevented mold from occurring on any of the interior walls.


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## pen (Mar 24, 2015)

Charlotte987 said:


> more than a foot of plaster on the inside



Good lord!  I can only imagine the weight load a wall like this must produce!


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## Charlotte987 (Mar 24, 2015)

pen said:


> Good lord!  I can only imagine the weight load a wall like this must produce!



The house has a six foot thick and about seven foot high rubble stone wall as its foundation, the basement windows look like a cave entrance. I think the original builders thought they were building a fort and wanted it to be strong. When I first moved into this house, I looked for arrow slits in the walls. So the fort-like basement can handle the plaster load of the upstairs walls so far. And if there's a war, well, were covered.


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## Ashful (Mar 24, 2015)

Foot thick plaster on the interior of a framed wall?  Surely I must be reading this wrong.


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## pen (Mar 24, 2015)

Joful said:


> Foot thick plaster on the interior of a framed wall?  Surely I must be reading this wrong.



Did you see where she lives! In that climate, I wouldn't doubt an old structure would be built like that to try and survive!


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## Charlotte987 (Mar 24, 2015)

Joful said:


> Foot thick plaster on the interior of a framed wall?  Surely I must be reading this wrong.



No, you not reading this wrong, the two upper stories straddle and are attached to a six foot thick rubble stone foundation. This is not a conventional made from plans home, it was built by someone without plans or much knowledge of building. They built the foundation, added a chimney then built on two upper floors. The upper rooms of the house are attached to the subfloors with forged iron straps that attach to the structural beams. It's a strange way to build, and my neighbors interior walls are even thicker, they must have been built by the same person or persons. The houses date to before the 1820's, which is when they were likely sold for the first time.


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## DougA (Mar 24, 2015)

My guess is that it has a lot more than just plaster in it to be a foot thick.


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## delp (Mar 25, 2015)

that is amazing, Charlotte987!  Have you made any holes in those walls to see how they are built? I just can't imagine anything other than a buttress-type gradual slope up to the top of the wall. Please post pictures Also, 6' thick rubble basement walls?! More pictures!!


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## velvetfoot (Mar 25, 2015)

delp said:


> 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 read all the comments on that link.  Quite the eye opener for me.


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## Charlotte987 (Mar 25, 2015)

delp I don't want to hijack your thread, but you asked the question and yes it looks like its buttressed. Hope you found some solutions to the cold wall problems? Or at least something to consider and ideas to work from?








1st Back of the house, its built with a thicker end near that bottom, and slopes up.
2nd Interior basement window with about two inches of spray foam.
3rd Interior basement door to the garage, door is about five feet high.
4th Exterior wall with snow.


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## Ashful (Mar 25, 2015)

Wow...


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## EatenByLimestone (Mar 25, 2015)

Charlotte987 said:


> No, you not reading this wrong, the two upper stories straddle and are attached to a six foot thick rubble stone foundation. This is not a conventional made from plans home, it was built by someone without plans or much knowledge of building. They built the foundation, added a chimney then built on two upper floors. The upper rooms of the house are attached to the subfloors with forged iron straps that attach to the structural beams. It's a strange way to build, and my neighbors interior walls are even thicker, they must have been built by the same person or persons. The houses date to before the 1820's, which is when they were likely sold for the first time.




Probably figured out they'd make a stand on your block if those crazy Americans ever invaded again!


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## delp (Mar 26, 2015)

Thank you for the pictures, Charlotte987! That's amazing. No, you haven't hijacked anything, conversations evolve and wander wonderfully sometimes. The only "solution" I'll try next winter are some tall curtains on the wall. Since the wall runs next to the stairs there's no room to build a bookshelf, although that would be a great looking, albeit, massive bookcase!


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## Ashful (Mar 26, 2015)

What I'm learning, in a very similar situation, is that you just can't hope to heat uninsulated stone walls.  Mine remain at 52 - 53F, pretty much all day, every day, for the entire heating season.  Radiant heaters are completely ineffective, in this situation.  This is probably why I've never been able to put as big a dent in my oil bill, as I think I should for the amount of wood I'm burning.  My baseboard heaters are convective, and very effective, whereas my stoves are radiant.

Heat the air, give up on those walls.  Thus may be the cost you pay for the cosmetic appeal of an old house.


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## Charlotte987 (Mar 27, 2015)

Used to live with roomates years ago as a student. We rented huge old, drafty apartments in the city. One that I recall was an entire partitioned ballroom in an old mansion. The front wall of the largest room had enormous leaded windows and was grey stone facing block with an inner course of brick, which had about an inch of plaster on top. In winter the wall would have frost on it. One of the students was studying engineering at the time and we all got together and decided to build a temporary wall on top of the the cold wall. It was made to be put up in winter and taken down in the summer, made only of non-organic materials, plastic panels were sandwiched on either side of pieces of rigid insulation. We couldn't damage the wall or attach anything to it, and because the materials were light weight we duct taped it to a metal curtain rod that we attached temporarily to the walls, in summer we removed the temporary wall, but it did work, it just was not all that pretty. It made a difference in the temperature in that room and worked like a false wall, there was no mold on the walls when we took it down in the summer. It's certainly an idea that could be worked on and developed.


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## renewablejohn (Apr 8, 2015)

Ashful said:


> What I'm learning, in a very similar situation, is that you just can't hope to heat uninsulated stone walls.  Mine remain at 52 - 53F, pretty much all day, every day, for the entire heating season.  Radiant heaters are completely ineffective, in this situation.  This is probably why I've never been able to put as big a dent in my oil bill, as I think I should for the amount of wood I'm burning.  My baseboard heaters are convective, and very effective, whereas my stoves are radiant.
> 
> Heat the air, give up on those walls.  Thus may be the cost you pay for the cosmetic appeal of an old house.



Dont give up on your stone walls. Here in UK we live in a listed farmhouse dating back to approx 1650. It has 2 foot thick stone walls and was basically a fridge with all the heat exiting through the single glazed windows. In UK we have very strict rules on refurbishment of listed buildings   but have just installed triple glaze glass direct into the stone mullions and the difference has been amazing obviously the heat was escaping through the windows not the stone walls.  To protect the fabric of the building from condensation the house is fitted with individual MVHR units in all kitchens and en suites.


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## Ashful (Apr 8, 2015)

Thanks, John.  We have all original 1770's windows, but a prior owner fitted them all with high quality triple-track (common in USA) storm windows.  Those triple-tracks are now at least 30 years old, and tired, and I've been replacing them with traditional wooden storm windows.  I find that the radiation loss from my old windows with storms is actually much better than my modern windows in our new addition, the modern windows being Andersen 400 series double-glazed with low-E glass.  My primary enemy with the old windows is draft, and while I could install interlocking metal weatherstripping on each sash, the old house purist in me has resisted the idea.

Really, we don't do that bad, considering the size of the house we're heating.  My comment about the stone walls was still valid, they do hold 52F, no matter how warm the air may be in the house.  However, I think the majority of our heat loss is actually our attic and one small 1890's addition (800 sq.ft.), which is a framed building.  We will be mostly demolishing and rebuilding that addition, in the next few years.


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## woodgeek (Apr 8, 2015)

My buddy with a stone house (cotswold cottage style) has a remarkably low heating bill.  As I understand it, there is an outer and inner stone wall, connected by tie stones, and the cavity is filled with loose stone 'rubble' that is low thermal conductivity.  Also, rather airtight when compared to most timber construction.


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## renewablejohn (Apr 10, 2015)

woodgeek said:


> My buddy with a stone house (cotswold cottage style) has a remarkably low heating bill.  As I understand it, there is an outer and inner stone wall, connected by tie stones, and the cavity is filled with loose stone 'rubble' that is low thermal conductivity.  Also, rather airtight when compared to most timber construction.



Similar construction to our house with all the heat originally going out through the roof. We now have 4 inch insulation between ceiling joists with a further 4 inch across ceiling joists and finally 4 inch between rafters.  Prior to insulation the house was heated with 65kw oil fired boiler now we have a 20kw Dunsley Yorkshire wood boiler running 11 radiators.


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## TonyVideo (Apr 20, 2015)

I have an 1880's home with 3 layers of brick on all outside perimeter walls. I have 11 foot ceilings on 2 floors with 3,000 sqft total. I real bear to heat. I have a 175,000 btu gas furnace that does OK until it gets to below zero then it runs non stop. All this brick is one huge heat sink. I quit dropping the Temps at night as it took too long to get back up to normal temp. Last year added 2 pellet stoves in two areas downstairs. Furnace at 65 and zone heat with the stoves to 70-72 when we are in that area of the house or home moving around. This has worked great for us. I gave up trying to heat the whole house consistently. The key I learned was to set the furnace and leave it alone. I used more gas raising and lowering it trying to save gas even before the stoves. The stoves added a level of comfort when needed. 2nd floor stayed above 60 even on the coldest days which we like for sleeping. I would love to find a way to make it better but an old house is an old house. There are small things I can keep doing and will continue. Good luck.


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## Ashful (Apr 20, 2015)

Eleven foot ceilings in 1880's brick?  Please measure twice!  That is one odd-ball house.  Common would be 9' first floor, with 8' or 9' on second floor, for 1880's brick or stone houses around here.  I have owned several.


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