Old house, expensive steam heat, suggestions??

George_14

I have a multi family 1880 victorian house in Rhode island and 3 apartment units (1 on each floor).  All heated with 3 seperate steam boilers.  2 oil (1st and 2nd floor) and 1 gas top floor.  We rent the 3rd floor out as a winter rental and would like to get thoughts on how to make the heat more affordable for the tennants without putting a whole new system in.

It's 1 pipe steam (1400 sqft apt) 

radiators are approx 25 ft above the boiler in basement (tall ceilings)

Ceilings in the apartment are 10-11 ft.

Boiler is approx 15 years old (weil mclain)

I don't think the walls have any insulation

attic is insulated but could probably use more (there's probably 6-8 inches)

windows are single pane with storms on them.

I'd like to make it more affordable.  What would be the most bang for the buck.

insulating walls?  more insulation in the ceilings?

If I was to try something to get better zone heating (just 1 or 2 rooms) whats my best option?  electric or oil filled space heaters? or how about thoughts on a mini split heat pump?  or the p-tac units?

Thanks for any thoughts.

George

Steamhead

Insulation

would be my first step- actually, in my own house it's been an ongoing first step. Also, all your steam pipes should be insulated too.



Then see if it takes more than a couple minutes from the time the boiler starts making steam to when it arrives at the radiator shutoff valves. If it's much longer than that, the air is probably not being vented properly.



Also, the boiler may be out of tune. This requires a pro with proper test equipment to fix.



Have you tried the Find a Contractor page of this site?

The Steam Whisperer (Formerly Boilerpro)

Yes, cut heat loss first....

and make sure your boilers are in good tune.  Air tightening is the biggest typical improvement followed by insulation.  If you want some zoning, add TRV's (thermostatic radiator valves) to your one one steam radiators.  They can provide great control on a room by room basis, but you do have to be careful that not too many radiators are off at one time.....this leads to inefficiency and other problems.

George_14

I was hoping you weren't going to say that

I did use the find a contractor page but there were none wihin 10 miles.  I do know a few HVAC guys that clean the boilers for me.  I'll give them a call.

Who do you recommend calling for insulation?  I guess I will need to blow it in through the walls.  I understand it's pretty expensive?

What's the best way to determine when the bolier is generating steam?  I usually just feel the pipes near the boiler. 

Should the vertical distance from the boiler to the radiator matter much?  I had thought that maybe steam was not a good option for the 3rd floor since it has to travel so long to get there (25 vertical ft)?

Thanks much!

George_14

TRV's

Ok, I'll seal up the leaks and get some insulation quotes.

Do you think the TRVs are a better option than turning the thermostat down on the floor and using space heaters for a couple of rooms?

If so, any thoughts on what would be a good space heater option?

Steamhead

With steam

you may have to search past 10 miles.



I use the same method for determining when the boiler starts making steam.



An insulation contractor has the gear to blow in more insulation. Find one who knows old houses. Insulation is cheaper than the extra fuel you use year after year.



If you vent the air properly, 25 feet is not far at all. With the right vents, you can fill a main hundreds of feet long with steam in a few minutes.

George_14

slow heating radiators

Ok glad you cleared that up for me.  Then I must have something wrong with the system.  What is the most likely issue if I have some radiators that take a long time to heat up?  I'm sure it's not the vent because I can take the radiator vent off and it will still take a while.  Could the pipes be clogged in some way?

Rod

1 Pipe Steam

Hi George-  Steam travels in all directions, even straight up for 1000 + feet! The Empire State building is steam heated at less than 2 PSI steam pressure, 

There is a very good book offered on this site which might be helpful to you. It's called "We Got Steam Heat". It's humorous, easy reading and written so a homeowner can understand it.  I'm a homeowner and the knowledge I got from it paid for the book several hundred times over in saving me fuel and increasing my comfort.

http://www.heatinghelp.com/products/Books/5/61/We-Got-Steam-Heat-A-Homeowners-Guide-to-Peaceful-Coexistence



The fellows who replied to you, Steamhead, BoilerPro, are very experienced steam pros and I'd definitely follow any advice they give.  With a bit of a tune up your steam systems should be able to provide you with plenty of heat. Electric space heaters etc are going to be far more costly to run.  I've attached a drawing of a typical one pipe steam system. Can you identify on your own systems where the different labeled parts are located, especially the main vents?

Steam Pipes generally don't clog up.(they're steam cleaned!) The Wet Return pipes can clog if not cleaned fairly regularly.  Let us know whether you can locate the  main vents on your systems. (These aren't the vents attached to the radiator.) They usually look like a can of tuna on its side or a bullet pointed straight up. If there is any writing or numbers on them let us know what they are. 

- Rod

Jamie Hall

Several thoughts...

First, you will certainly have to go beyond 10 miles to find a decent steam guy -- but there are several in the Boston and Worcester areas who are very good.  It is worth it; most HVAC guys, however good they may be, have only a very sketchy notion of how a steam system works.



And yours does need a tuneup.  Probably more venting on the mains.  The cottage I superintend has mains over a hundred feet; none of them take more than about four minutes (and I regard that as long -- I'm working on it).



Attic insulation is the first step, though.  I specified Icynene on the underside of the roof (which is exposed) -- 8 inches of it (rafter depth) -- and am very very happy with the results.  This is in addition to about six inches of fiberglass on the unfinished parts of the attic "floor".  Wall insulation is a little more iffish, although in an 1880s house you shouldn't have too many odd framing situations so it should be possible to have it blown in without too much havoc on the walls inside.  I am a little of two minds with the stuff, though, as there is no vapour barrier unless you demolish the inner wall surface, install a vapour barrier, and put the inner wall back -- and if you were going to do that, you might as well use Icynene and do it right.  Since the inner walls in my place are plaster, and since the place is National Register, that isn't an option -- and as a result there is no wall insulation, nor is there likely to be!  Windows are another matter.  There is no need to replace them, but you need to make sure that they themselves (I presume they are double hung?) are reasonably tight.  Then the storm windows also need to be tight.  Look for draughts and follow them up and eliminate them (this applies not only to windows -- how about electric sockets on exterior walls?!).



I can't possibly recommend space heaters, except possibly briefly in, for instance, a bath room to help the occupant keep warm after a shower.  The electric variety are hideously expensive to run, oil filled or not, and any of the fuel fired sort have, in my humble opinion, no place in a residence.  Just too dangerous (so are the electrics, for that matter).



Best bang for the buck?  Tune up your boiler and steam system, then more attic insulation, then tighten up on infiltration, then see where you've gotten to.

David Nadle

Insulating old walls

Jamie,

I've got an older home with uninsulated plaster walls and I've been considering blown cellulose, both in in the rafters & attic (It's a Cape Cod) and in the walls.



I'm wondering where your concerns about retrofit insulation without a vapor barrier come from. I've seen many claims on the internet on both sides of this issue. It seems to me the industry is highly uncertain on what causes moisture problems and how to prevent them.

 

The Steam Whisperer (Formerly Boilerpro)

Vapor Barrier for existing walls..

If you do a search you should come up with a vapor barrier paint that can be used to provide a vapor barrier for your walls.  Also, several layers of oil based paint can be effective too.  I believe I used a paint made by a manufacturer in Chicago.

Jean-David Beyer

Cape Cod ...

I have a Cape Cod that was built in about 1950 or perhaps 1955. The exterior walls were insulated with "builders batts" that were at most 2" thick I do not recall if those walls were built with 2x4s or 2x6s (probably 2x4s). The inside surface are plaster. I inherited some money, so I had urea-formaldehyde insulation foamed in. We did not know about outgassing in those days, but by now the gas should be pretty much out of there. THe only vapor barrier would be the plaster on the inside. I imagine the urea-formaldehyde foam is more resistant to humidity than cellulose or blown-in fiberglass would be.



I do not suppose anyone puts in that kind of foam anymore, but there meay be other foams that are a bit safer.

Jamie Hall

Vapour barriers

are a vexed question, aren't they?!  Actually, I have seen a good bit of information on both sides -- and I can think up good, even scientific sounding! arguments on both sides as well.  Not only whether to vapour barrier or not, but also on where in the depth of the wall/insulation package the vapour barrier should be.  I think that for me the bottom line is that I don't want condensation to happen within the wall structure -- so I really have only two choices; a vapour barrier very near the warm, humid side or, to be honest, enough circulation -- breathing -- within the wall to keep the dewpoint below whatever the temperature of the materials in the wall structure are.



Which, in my ark of a cottage, so far has meant allowing the wall structure to breathe through the clapboards and sheathing on the outside, counting on the plaster on the inside to keep infiltration down to a dull roar (which it does a pretty good job of).  Not the best energy efficiency, I'll be the first to admit.



The Icynene foam I used in the attic spaces does not outgas anything particularly evil, unlike the old urea/formaldehydes, and is itself a vapour barrier.  I'd love to use it in the walls, but my installers refuse to guarantee that it won't damage the plaster as it expands in place (I don't blame them) -- and that would be a disaster.



I've looked into the vapour barrier paints, and it does appear that they work at least moderately well; if your plaster (or plasterboard) is paintable, that might be a very good way to handle the problem.  Then blow in the cellulose or whatever doesn't expand.  If I could paint the plaster in this place, I might well try that (I can't; you'd be amazed at the things you can't do with a National Register place...!)

David Nadle

Vexed is right

I've read all over the net on this issue, including various building science and green building sites, The more I read the more confused I get, and I don't think it's my fault. There's a problem with the current science. Models don't work in the field, recommendations change every year, frequent reversals on issues like dew point within the insulation, etc.

 

My personal position is that in my locale (Northern NJ) any vapor barrier will be on the wrong side for half the year, so it's better to not have one and instead have moisture tolerant walls that can dry in both directions. Tightening up my house at this point is a comfort issue even more than an energy savings issue. I'm tempted to take a chance on cellulose but every time I hear from someone in my position who avoids insulating their walls I get skittish.

Brad White

Icynene as Vapour Barrier/Retarder?

HI Jamie

I have to take exception to the notion of Icynene as a vapor (ok, ok Vapour!) barrier. It is an open-cell foam with a perm rating in the range of 16 at 3" thickness and 10 at 5" thickness is pretty well documented. Absent a formula change, this does not approach the perm rating of 1.0 to be considered a Class II (or Class vapor retarder.



The closed cell urethane foams tend to meet this Class II/Class B vapor retarder standard with perm ratings of less than 1.0 but greater than 0.10. Of course with all foams, thickness plays a role; the perm rating is not absolute as with other materials. Must be an internal befuddlement factor of some sort.



But on the positive side, about 90 percent of moisture driven in and through uninsulated or semi-insulated walls is by airflow with associated moisture. Vapor pressure accounts for the difference. This 90-10 rule of course can be 80-20, but point being, the motive force of vapor pressure, absent an indoor sauna, is over-stated in most cases.



The point within this though, is that a dense-pack cellulose, foams and the like, being decent air retarders, also hold back the bulk of air-borne moisture. A house so insulated THEN would have vapor pressure as the largest motive force. But with proper indoor ventilation, this too can be mitigated.



Anyway, my $0.02



Brad

Rod

To Insulate or Not to Insulate

To insulate or not insulate an old house is a problem here to in Maine too.  There have been some who several years back went with blown in cellulose only to later develop tremendous dry rot problems from trapped moisture / no air circulation  The only insulation jobs that could be considered really successful were those that stripped off the clap boards and the lath & horse hair plaster down to the bare studs and then rebuilt from scratch. This group seems to be confined to mostly of owners who have moved up from the big city and are doing a big renovation anyway.  For insulation most of these seemed to go with board foam with expanding foam squirted in to fill the voids. (I found out that out that one of the reasons for this is that since the old studs are actually dimensionally 2x4 that you can get two layers of 2 inch foam to easily fit!)



The rest of us just sit on our hands knowing insulation would be a tremendous improvement but we're afraid of some unseen time bomb and therefore do nothing. I've insulated my attic and the basement ceiling and that has helped some but what to do about the walls remains a riddle.

I was surprised on hearing about Jamie's problem of not being able to paint the plaster as I would have thought most old plaster would have been painted by now so that it wouldn't reallymatter  I'm really interested in this discussion as rising fuel costs are going to force me to do something in the near future.

- Rod

Brad White

George

You actually are in a good position, having no known insulation in the walls. Having "partial" insulation (whatever that means and I hear it all of the time), often means that you cannot easily bring the wall insulation up to current standards.



Typically in an older un-insulated or under-insulated house, the "Heat Loss Pie" might have the following apportionment in terms of loss:

Walls: 30-35%

Infiltration: 25-35%

Glass: 15-25%

Roof: 10-20%



Now, these proportions vary, but the attached is from an 1880 three-story house in Dorchester MA, as a comparable from several years ago. (EDIT: The file would not open so I deleted it, but the text above represents the approximate values.)



Consider too that if you insulate your walls, the other values do not change but their proportions change, appearing larger. This does not mean that they have grown.



Usually the largest and least quantifiable pie piece is infiltration, the uncontrolled leakage of air in and out of your structure. The good news is that infiltration can be addressed across wall insulation, glass (storm windows or new windows), roof insulation. Take care of those in the right way and you help reduce infiltration by default.



Here is what I usually advise be done in situations such as yours, in very general terms:



Assuming your heating system is not running just horribly, I go by the axiom that "insulation is fuel you pay for once". If that insulation also helps reduce air leakage, that is a Mitzvah. It should and you should do it.



1. Air seal with expanding foam around the perimeter rim joists, especially if you are balloon-framed. (You likely are.) This is a good way to put a cork in the bottom of any open stud cavities which helps wall insulation, item 2. Air seal in the attic if you can, around plumbing and wiring passages and around the chimney with sheet metal and fire retardant foam. (Check local codes. Some jurisdictions want this kept open regardless, so you admit defeat). Air seal before insulating though, is the point.



2.Insulate the walls with a dense-pack cellulose or low-pressure foam system. I say "dense pack" because of the higher air-stopping/slowing properties of the installation. Sealing the base rim joist is a good way to start as noted above. Too many installations have had a lot of fluffy basements.



3. Top off the attic insulation, if an open attic not used for storage, with an over-spray of damp-spray cellulose. While this may compress fiberglass if that is what you have, the crust formed also forms an air barrier at least in part.



4. Storm windows: If replaced, caulk around the frames, using the good stuff. Fail to do this and you cut their effectiveness by half. Expensive caulk is cheap. Cheap caulk is expensive. Good storm windows are an excellent value compared to replacement windows. They are often better than the prime windows they cover.  While you are doing this, weatherstrip the prime windows. Windows are a topic of their own, do not get me started.



While planning the above, yes, check out your steamers, venting, all good things. A good steam system is a wonder to behold. Before I came to this site, steam was the red-headed step-child of heating systems. Now, to me, it is beautiful when at it's best.

David Nadle

Cellulose

Brad, great to see you on here again. I agree on icynene not being a vapor barrier. When I was considering doing a cathedralized attic--I've abandoned that plan--I'm pretty sure I learned that by code only closed cell was acceptable against the roof deck. But you always see cathedral ceilings done with icynene on their websites, so I don't know what's going on.



Rod, I wonder if some of the past problems with blown-in cellulose have to do with loose fill vs. dense pack in the wall cavity.

Jamie Hall

Thanks, Brad

for the info on Icynene -- I hadn't had the exact number.  I kind of agree with you -- the main advantage to it is that it reduces air flow considerably.  The other, rather intriguing one, from my point of view is that when it's cold out, the dewpoint will be somewhere in the foam -- which doesn't care!



The plaster is odd -- most houses would have had the plaster painted at some point, but part of this cottage is a "shingle style" with "arts and crafts" bits -- which means sort of Victorian country.  And rough plaster.  Which, however, is both thick and astonishingly tight  Some of the rest of it is 18th century -- and again the plaster was never painted (it was wallpapered, though, which is a headache of a different sort).



Fun, isn't it?

Brad White

Fun? Yes!

Hi Jamie-



Where does one find this intriguing cottage of yours? It sounds like an idyllic place.



That notion of vapor barriers inherent in paint (oil based, aluminum paints and others since), has always had me saying, "better than nothing". My rationale is the discontinuity of the barrier layer. It stops at ceilings (where calcimine tended to rule the roost) and floors where wood meets wood, varnished at best. So, I had to hang my hat on the walls passing moisture in both directions and not holding it.



My last house, an 1873 balloon-framed farm house, I had insulated with Certain-Teed Insulsafe II, back in 1985. In 1999, 14 years later, I totally gut-renovated the second floor. The material was as densely packed as felt and I retained over 90 percent of it. Where I removed some, the walls were as dry and sound as any I have seen, so no moisture issues that I could tell. Finishing that space, I added an inch and a half of foam covered polyiso board, strapping and a blueboard/veneer plaster system, so tighter still. Point being, no moisture issues without any known vapor barrier.



The Icynene vs. Urethane debate goes on. Permeance aside, we know that Icynene has the same R value as "theoretically best" fiberglass, but Icynene has a much higher integrity installed. Being flexible, it tends to conform and ride with expansion, contraction and settlement.

Urethane tends to be denser and double the R value, but can be brittle, or rather, less flexible. Absent going back in and opening a wall after a time, no one really knows if it pulls away. My ideal system has continuous insulation on the outside, but in retrofit applications, this does not seem to pay for itself unless you are already stripping off the siding and can amortize that cost.



Apparently, life is our hobby, is it not?

D107

Fun it is

Yes, great to have Brad back. As a HO, one of my favorite topics. This thread has some great posts on the Great Vapor Barrier Paralysis. Fwiw I have a 1924 balloon frame colonial; we had blown in cellulose some years back, all from the outside. They cut two or three clapboards at the ends, drill the two inch holes on 16in or 24in, blow in the cellulose, plug the holes and put back the clapboard. (Have to seal the basement rim joists with fiberglass so the dense pack doesn't push through there result in a Laurel and Hardy scene.)



The cellulose acted as a sound barrier as well. The only vapor barrier there was the old black roof paper i think they call it; whatever clapboards were opened, that row of black paper was removed, so otherwise that's intact and probably not as strong a barrier as that Tyvek stuff is. We did a kitchen renovation a few years later and had to open up part of the east wall and found no rot--and fyi we had installed 3/4" styrofoam boards--somewhat permeable--and vinyl clapboards over the original wood clapboards. This is about 50 miles above NYC. Based on rough measurement of heating expenses/degree days before and after cellulose insulation, our estimate was savings of 25%.



I will say that if I had my druthers I would have first foamed the 2nd floor rim joist, then put the cellulose in. (We will someday foam the basement and roof rim joists which are more accessible.) I would have drilled holes in the main floor ceiling and foamed those rim joists up. Now with the cellulose there it would be a tricky thing I think without upsetting the dense pack, and those 2nd floor bedroom floors get COLD in winter, dense pack or not. Keep in mind that the dense pack tends to flood inward in this kind of house as the rim joists are often open to the interior.



Brad's percentages are interesting in that foam contractors like to claim that most of your heat is being lost through the roof--which is where they're mostly likely to do their work.

George_14

Thanks Brad!

Thanks for the tips! that sounds like some great advice!

I'm going to start with the infiltration and making sure my system is working well.

George_14

Thanks Rod!

I won't be down at the house till next weekend but I'll take a look and post some more info. 

I actually purchased the book from this site a few years ago and was able to fix the loud banging pipes that we were living with for years.  My wife thinks I'm a genius after none of the heating guys we had look at it could solve it.  No one believes me that it was a pipe in the basement that was not pitched properly that created the banging.  That book is great!

I had a feeling the radiators weren't heating properly due the the venting so I bought some good radiator vents (can't remember their name).  It helped some radiators but not others.  The size and proper location of the main vent is a little more complicated for me.  I'm guessing that may be my problem.  I'll try to post some info on that.  I do know one of the radiators that takes a long time to heat up shares a riser with another.  Is that generally ok?

Thanks,

George

George_14

Thanks Jamie!

Does anyone know a good steam guy willing to go to Newport Rhode Island?

How do I find one?

Brad White

Thanks for the welcome back, David!

I appreciate that. It is a great feeling.



Quick point on roof heat loss and roof insulation before I go off to bed. It is often a matter of area vs. the whole.



For example, a two story house measuring 30 feet on a side will have 2400 SF of gross wall area. (Forget windows for the moment, just gross wall area). The roof would be, say, 900 SF footprint if the attic floor is to be the thermal barrier and if the roof with some pitch, about 40 percent more than that, say, 1250 SF. With the layers of plaster, air space, decking, etc. your roof R value, uninsulated, might as well be uninsulated wall.



If the walls are 30-35% the roof can certainly be 40% to half that, or 15% to 20%. It all depends.



Now, a roof may have a higher delta-T because of the warm air hugging the ceiling, but that is maybe another five degrees. So the conduction losses through a roof are similar, a tad more but not exponentially greater than wall losses. (The air leakage up and out is the big culprit! Another tale.)



The question is, "why do the insulation folks recommend R38, R50, R60 in a roof or attic? Because you can fit it in there for not much cost per SF. Topping off an attic, adding 3.5 inches or so, unless it also forms an air seal on top of leaky old fiberglass, will rarely if ever pay for itself.

Rod

Need to find the Main Vents

Hi George-

On most steam systems there are two types of vents, Main Vents and Radiator Vents.

Main Vents-The Main Vent(s) are usually located at the end of the steam main (pipe) that takes steam from the boiler to the Radiator Laterals. (Radiator Laterals are the pipes that take the steam from the Steam Main to each individual  Radiator) The Main Vents can also be located on the Dry Return which is the pipe that leads from the low end of the Steam Main back to the Boiler. Main Vents are high capacity vents and allow the steam to push the air out of the Steam Main very quickly but as soon as steam reaches the Main Vents they close and steam is then routed in the Lateral pipes that lead to each radiator.



Radiator Vents- Radiator vents are the located on each radiator. They have (for a reason) a much smaller venting capacity than Main Vents. Their job is to vent all the air in the Radiator Lateral pipe and in the Radiator so that steam can enter the radiator. Like the Main vents they close when steam reaches them. 

IF there are isn't a Main Vent on each Steam Main or the Main Vent is inoperable, all the air in the Radiator, the Radiator Lateral AND the Steam Main must then vent through the much smaller Radiator Vent. This results in it taking a LONG TIME for the air to escape and steam to reach the Radiator. This is why Main Vents are so important!!



Another thing on a one pipe steam system is to make sure the valves on all the radiators are fully open and the radiators are properly sloped towards the inlet valve. Check the radiator slope with a carpenter's bubble level. I had a radiator that looked sloped properly but because the floor had settled was in fact sloped the wrong way! If you need to shim them up you can use quarters ($0.25) and stake them under the legs until you are satisfied you have the correct amount of slope and then cut a wood shim the right thickness. I have attached a drawing with info on 1 pipe radiators. 



Finding the Main Vents and sloping the radiators are things you can do yourself.  You'll still need a good "steam pro" to look over your systems and do the adjustments. I say "Steam Pro" as the average heating guy doesn't have a clue about steam. There are a couple of  pros located in Rhode Island. Go to Find a Professional at the top of the page, scroll down past the zip code area to where the "States" and you'll find a couple of guys in Rhode Island. I think one of them does hot water but I know Steve Gronski does steam.



I'd have a steam pro check your steam systems- boilers and burners annually.  I would think this would be especially important from the liability standpoint since these are rentals.



You mentioned having two radiators on one lateral that were slow heating . I'd get the main vents fixed first and then we can address this problem. Fixing the Main Vents may cure this problem in any case.  If you can, it would be a big help to take pictures of your three systems, especially the boilers and the piping around them.

- Rod

Rod

Double Posted

David Nadle

What would you do

My situation is -- 1920 balloon framed Cape. Finished upstairs with knee walls, side attics, and peak. Single dormer. Louvered gable vents and soffit vents. Side attics have plank flooring, 40 year old ratty fiberglass batts stapled to the roof rafters. If you even go near them they fall down. Several are already down. Condition/amount of insulation behind sloped drywall and above ceiling is unknown. Rafters are 2x8ish. The house is very drafty.



My idea for the roof was to remove all batts, cut into the ceiling a temporary access to the peak, seal all penetrations. Run plastic vent channel from the soffits, up through the sloped part, ending 18" or so above the ceiling. Staple fabric to the rafters in the side attics from soffit to the tops of the knee walls. Fill each bay (fabric part and sloped drywall part) with cellulose, and fill peak with cellulose. This way the side attics remain conditioned space and I can make use of the storage without trying to insulate and seal the knee walls and access doors, rip up the floor, etc. I think I'll get R-20 out of this plan, which is better than nothing, right?



I had thought that while I'm at it I should put cellulose in the walls... but I'm still wary. So what would you do?



 

Rod

Finest Kind Lobster, Insulation, and Clam Diggers Co-op

Hi David - You're probably right. I think it was just blown it with very little sophistication. Thinking back on it this, the time period was the late 70s - early 80s (Jimmy Carter - Save energy), there was a tax break involved and a suddenly lot of inexperienced people were in the insulation business. Building codes / contractor licensing at that time was (and in some areas still is) very loose or non existent.

A year or so ago I talked to someone who was knowledgeable about dense pack cellulose and was told that with dense pack, vapor barriers weren't needed and might even be detrimental.

And if there was a leak, the dense pack would absorb the moisture and then distribute it through out the dense pack where it would evaporate over time. While this might be true, the thought of having a "sponge" in my walls didn't do much to reassure me. Have you heard anything on this?

- Rod

Jamie Hall

northwestern Connecticut

is where the place is -- if your ever in the area, stop by and have cup of coffee!  Charles Garrity just did a nice job of installing a new Weil-McClain for me (this summer) to supply the steam for an original condition Hoffman equipped vapour system (well, not quite -- a couple of radiators have gotten moved...).  And life is our hobby!

Brad White

Pretty much what you said, David

The approach I would take is that fabric skrim with dense-pack cellulose, but then finish over it if you can with thin  tongue and groove planking to protect it if it will be exposed, (used for storage).  But as you said, seal first.



From what you describe, your house is as good as uninsulated, with all of those gaps. I liken that to wearing one of those snug full-length down stadium coats but leaving the zipper wide open.



One recurring detail I always come across in homes with knee walls is that air leaks under the knee walls and forms indirect paths to the outside, especially if the knee wall spaces are ventilated. I am referring to the condition where the insulation is on the floor of the knee wall cavity, runs up the knee wall, then follows the roof pitch up and then down the other side. If you have that condition, I recommend expanding foam between each and every joist.  But if as you say, you would be insulating the slope only, this would not apply to you.



The dense pack cellulose has appeal to me. My sister did her house with it (NuWool) about three years ago and no problems. We opened up a wall in her laundry room to put in a window and the material was dense, dry and no moisture issues we could see, this in a room where she hangs some laundry and with a shower nearby. (Yes, the bathroom is exhausted, she is not crazy.)



Being balloon framed, I would foam the rim joist with E84 rated foam, but start with a small bead to seal gaps, rather than a wholesale, "spray like a flamethrower" approach. One good bead does more good than ill-applied surface spray. Seal all pipe penetrations in the attic too.



Have you had a blower door test done? You may be surprised what you find.



Capes can be fun to retrofit and can make a nice tight shell if you sweat the details. Being small and with relatively simple geometry, you can see results with less fuss than say a Victorian.

David Nadle

Rim joist

Being balloon framed, the rim joist is on the inside and the studs go down to the sill plate outside of it. So any flaw at the bottom edge of the sheathing is like a big hole in the exterior, with near line of sight to the baseboards. Unless I fill at least the bottom of each wall cavity with foam or cellulose, spraying the inside face of the rim joist will give me bupkis, I think. That, and the fact that the walls are cold in winter, is leading me towards doing the walls as well as the roof.



Even though insulating the roof is complicated, I think it's less prone to failure and less work actually than insulating the kneewall and ceiling.



I'm having a blower door test done Tuesday. Should be interesting.

Brad White

Blower Door Test

How coincidental is that to my asking? Mmmm. Please send me the results off-line if you want a second opinion. I can compare it to my database, one I maintain of all the BD tests I have done. Hope you get a multi-point test, not just a single point CFM50 or ACH50 test. The multi-point test will generate a curve which will tell you if your holes are large and round (a lower curve exponent), or longer, thinner cracks, (a higher exponent).  Average exponent is 0.65 and I have homes that tested tightly in the 0.8 range and really loose ones down to 0.55. Oy.  Anyway, another tool to assist.



Re: balloon framed rim joists, some I have seen, most in fact, have the joists inboard and open all the way up. Some have been as you described. If so, that is a good thing, one cavity to fill. The ones that are open? What a mess.

David Nadle

Will do

Brad, thanks for your generous offer. I'll contact you with the results of the test.. (It's been scheduled for a while now, I didn't hop on the phone when you mentioned it ;-)



This is the year to do this stuff by the way. There's $1500 Federal tax credits from the stimulus bill (Cash for Caulkers).

Brad White

George

You are welcome. Keep us posted. This thread was yours originally but we all get to talking about related matters, which begets more questions and forms a web. One of the things I always liked about The Wall.



Where in RI are you? I am up in MA (Newton), so am just curious.

George_14

Are you interested in a trip?

Hi Brad,

Can I get you down to Newport RI for a look?

Send me an email at gdefina@yahoo.com if you are interested?

Thanks,

George

Brad White

Where in Newport?

Hi George. I used to live in Newport, part-time for several years, over on Annandale, so know it pretty well. I have friends there too, practically family and am due for a visit, I think.  Was just down there for the day a couple of weekends ago and barely checked in with them.



Write me off-line if you like. Could be worth a trip.



To be clear, I do not come to the Wall to solicit business, just not my style. But the challenges and love of the science and of learning is my motive.



Brad

Polycarp

infiltration and insulation

I'd second most of what Jamie has said.  The only thing I take issue with is the order.  The tune-up is first, but I'd put infiltration before more insulation.  Energy efficiency is my field and existing buildings are my specialty.  In most house that flirt with the century mark, infiltration is the #1 source of energy loss.  This is not to downplay the energy loss of no insulation, but to emphasize just how much energy is lost through those drafts .. both felt and un-felt. 



In most houses, infiltration-reduction is an even more cost effective measure than the equipment tune-up.  It usually is the best bang-for-your-buck thing to do.  However, due to concerns about equipment life and safety, it is usually best to do the tune-up first.  Tune-ups are especially important to the proper operation of steam equipment, so its an even better idea to prioritize the equipment tune-up with steam.

Brad White

Amen to that.

In another thread, Steve Ebels makes that case too, having abundant insulation negated by excessive infiltration.  My analogy is wearing a snug down stadium coat but leaving the zipper wide open.



After doing a fair amount of blower door testing over the past several years, my eyes never fail to open wider.  Never hurts to emphasize the importance of air sealing.

Polycarp

Vapor Barriers and wall insulation

Vapor barriers are indeed a tricky topic.  One of the important things to remember is that even closed-cell foam does not actually create a vapor barrier in most cases.  It creates a vapor sieve.  The inability of water vapor to move through the relatively impermeable foam just reroutes it through the relatively permeable wood structural members.  Unless the foam goes over the studs or there is a real vapor barrier, its just going to make the moisture go into the wood to cause problems.  Even open celled foam can be less permeable than wood, so this can even be a concern for this technology in a retrofit situation. 



This is why packed or blown-in-blanket cellulose has been gaining favor.  Its R-value/inch usually isn't as good as foam, but it is better than bats.  It does a good job of getting into crannies and otherwise reducing infiltration - again, better than batts but not as good as foam - but it still breathes enough to let any moisture that does get in get out as well.  It is typically more permeable than wood, so the moisture gets into it rather than the wood, which helps avoid the problems related with re-routing the moisture through the wood.  Most modern cellulose is also impregnated with boric acid, a natural substance that retards fungal growth and vermin.  And most cellulose retains its effectiveness even if it gets wet and dries out.



The movement of moisture in buildings is not exactly understood, but a safe bet is to follow the rule for old houses (and probably new houses too) that if you can't get a true vapor barrier, it is better to have no vapor barrier at all.  A good vapor barrier keeps moisture out of the insulation and structure, a bad vapor barrier kind of keeps moisture out of the insulation and structure, but kind of keeps it in too.  And dry rot isn't the only concern.  There are various salts everywhere, and the dissolving and recrystallizing of those salts in wood as vapor moves through condensing and re-evaporating will break the wood down.



Edit to add:  This is why good moisture control *in* the house is so important.  Those bathrooms and kitchens need good vent fans that actually go outside.  Most heating systems naturally de-humidify, so if you can get water saturated air out as soon as it's produced, you simply won't have a lot of moisture around to cause problems in the envelope.





As to wall insulation, I actually put it at a fairly low priority.  It isn't that it isn't effective, but that its cost-effectiveness is lower than a lot of other measures.  The fact is that you aren't going to get a lot of insulation in most walls and it is going to require a lot of effort to do so.  And unlike what was said below, you aver *very* likely to find odd framing situations cause blockages in a lot of older houses.  Not to mention the very real danger that you could do damage to the walls.  I'm not saying don't do it, but there are a lot of things you should do first (besides infiltration, roof insulation and equipment tune-up as mentioned above).



Despite the smaller overall area, even extra roof insulation is superior for a couple of reasons.  Obviously first, it is generally more accessible and allows for more insulation.  But there are other factors as well.  The delta-T of warm air at the ceiling to outside air mentioned above is part of it.  But heat traveling up through a house and through the ceiling also creates a mini-stack effect in the house.  This gives extra charge to whatever infiltration you do have.  Additionally, we perceive temperature in three ways:  conduction, radiation, and convection.  Conduction and radiation far outweigh convection.  Since our heads are typically most uninsulated body part - both naturally and by clothing - having warm surfaces at the ceiling is more important than you might think to thermal comfort.  This is why electric resistance coils in ceilings were a relatively efficient heating system even though resistance technology is a horribly inefficient way to produce heat.



I'd consider beefing up the windows with interior or exterior storm windows to also come before wall insulation.  This can also help with the infiltration problem.  Even window treatment can make a big difference.  Those windows are big radiant bodies just making you feel cold and heavy curtains can make a huge difference.



Equipment upgrades even often come first, especially for old equipment .  This is especially true of refrigerators, AC units, washers (there's not much you can do to make a dryer more efficient, but how well the washer wrings out the clothes first makes a huge difference), water heaters and, of course, your heat source or heat delivery system.



I like to put it this way.  You have so many energy efficiency dollars to spend.  You want each of those dollars to save as much energy as possible.  If you haven't done or disqualified these other things first, you aren't going to maximize those energy efficiency dollars by putting in wall insulation.

Brad White

Very

well-said, Polycarp. A lot of good information.



Where I might gently intercede is the priority on wall insulation to the extent that dense-pack cellulose and similar systems reduce air infiltration. That is a point we both agree on, reduction of infiltration first.

Wall insulation, done densely, will achieve both transmission and infiltration reduction.  The very fabric of a wall is often so porous, through siding, sheathing, dusty old felt and plaster, to air, it is just a small obstacle course.



But your point regarding cost effectiveness is clear. Blowing in wall insulation is a project and absent other measures, may well spend more for measured benefit than any other single measure. But for a large step, it is one I find gives greater comfort, especially if windows are in good shape, with storm windows, etc. The noise reduction, "stillness" and higher MRT at the walls, all good. Thermally speaking, the ROI is fairly decent, averaging five years in my experience.



As to attics, yes,  accessibility makes that effort sing.