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In need of frugal, common-sense insulation advice  RSS feed

 
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Hi friends,
I live in a shotgun house in New Orleans. The house is marvelous. It is also cold in the winter and hot in the summer, and when the rain falls, like it’s doing now, it pounds on the metal roof loud enough to make conversation a trial.

My little house is over a century old and is framed in a way that may be uncommon to most of y’all.  Instead of stud framing, the walls are made of bargeboard planks that run vertically from the sill to the top plate. (In the 19th century, folks upriver would float their wares downriver on homemade barges, which would be broken up at the port and sold as building material to working-class people.)

The bargeboard is about an inch and a quarter thick and ranges between 10 and 13 inches wide.  There are some remains of plaster chinking between the planks, but plenty of gaps, covered over with battens.  Seems like the walls were designed to not be airtight or vaportight, so that the house could dry out between rains.
Oftentimes in these old houses we see where people have tried to add on modern things like spray-foam insulation or even fiberglass insulation, but seems like inevitably water gets in and is then stuck  there to make a wet wood feast for the termites.

It has a hip roof.  There is no continuous roof decking; rather, the roofing is supported by purlins a true inch thick. There is about a three-inch gap between purlins.  The rafters are true (not nominal) 2 x 4s.  They are spaced 32 inches on center, more or less.  The ceiling joists are true 2 x 6s and originally the house had a tongue and groove beadboard ceiling. Now, though, it is open to the rafters.

Like most houses around here, mine is on a pier foundation.  Normally our floors are uninsulated, but at one time I had access to a bunch of rigid foam insulation, which I nailed up on the outside bottom end of the floor joists.  I sincerely doubt it is airtight, but at least now I don’t see the cold ground between the cracks in the floorboards, and that helps me feel warmer anyway.

My windows are leaky and single-paned and cannot be replaced.

Which is all to say, the house doesn’t offer much in the way of cavities to stuff full of insulation.

The roofing material was originally asbestos shingles with a tarpaper underlayment. That has been removed and now there is a metal roof with a reflective sheeting underlayment.  Because there is no gap between the metal roof and the underlayment, it is just functioning as a water barrier, not as a radiant barrier.

So, on the off chance anyone has stayed with me this far, can you recommend anything that could help me keep a tad warmer in the winter and cooler in the summer? 
When I look on sites like greenbuildingadisor I don’t know whether to laugh or cry, because the “building science solutions” they prescribe bear so little resemblance to the world I and my neighbors live in.
784ADB8C-BCE3-4D73-B0FA-9767FC0C8C42.jpeg
[Thumbnail for 784ADB8C-BCE3-4D73-B0FA-9767FC0C8C42.jpeg]
Photo of my roof
 
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Location: Zone 4B, Maine, USA
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Howdy! Thanks for sharing! That is a fascinating way of house building I had never heard of. I'm still pretty new to building so I always like hearing about different building styles.

Are you willing to to attached some kind of sheathing to the bottom side of the rafters? That'd create a 36" wide bay that some kind of insulation could be placed in. Though you wouldn't get to look at those cool purlins anymore :) Though reducing the sound of the rain might make up for that? :)

If sheathing were attached to the rafter bottoms, would the insulation bays created be likely to get water in them? If not then some kind of cellulose might be a cheap insulation... of course 4" isn't going to have a huge R value. But it's not nothing either.

I'm afraid I'm totally stumped by the walls, however... I can't imagine life in termite land! I just have to put up with 2 foot snow storms in the middle of March :-P
 
Shannon Holman
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Thanks for your reply, Bobby!  I get numb when it’s below 50 so I can’t say I’d want to trade places with you...except for maybe six weeks in summer

Your suggestion about filling the rafters bays reminded me that a while back I came across a fellow elsewhere in Louisiana who uses rice hulls as wall insulation in new double-stud construction. Rice hulls are cheap and plentiful around here, not too heavy, and not as attractive to pests as cellulose, so maybe I can revisit the idea for my roof.  I wonder if my best bet would be to staple a heavy burlap or canvas to the rafters and blow the rice hulls in.

Back in the day, people around here used whatever was handy to build with, so you can find some interesting things during demolition.  In my house we found a bunch of big sheet metal signs nailed to the bargeboard behind the layers of moldy Sheetrock and layers of wallpaper. 

 
pollinator
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Location: Southern Arizona. Zone 8b
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Foam board insulation.  They sell it in  4ft x 8ft sheets with various thicknesses, you can usually get it up to 2" thick at Lowes, Home Depot, etc.

Two common types of foam board are Styrofoam and  Polyisocyanurate  Both will provide good insulation even when wet and they will block the wind.  Butt them up together on the outside of the shack and tape over the seams to block all wind.  You can then do either stucco or siding on the outside of the foam.

Styrofoam provides about R3.5 per inch,  Polyisocyanurate is about twice as good, but costs 50% more (still the better deal) 2" of Polyisocyanurate provides the same R-Value as 4" of fiberglass, it's actually even better than fiberglass because normal walls have 2x4s that bridge the gap between inside and out and lower the R-value of the wall.

Or you could put them on the inside and lose a little floor space, insulation won't be quite as good since you'll end up with interior walls etc. bridging the gap.

It's not exactly cheap, but compared to the cost of heating and cooling will probably pay for itself in a year or so.
 
gardener
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Location: Upstate NY, zone 5
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I think the best bang for the buck would come from insulating the ceiling. To keep the space as high as practical (there was a reason that old buildings had tall ceilings), I would suggest styrofoam or other rigid board insulation fitted between the rafters, at least 2" and up to 4" thick depending on what you can afford. You would want to leave an inch or more of ventilation space between insulation and roofing. Seal the gaps between insulation and roof joists with expanding foam, then cover the bottom with a fire-resistant material - I'm not sure what beside sheetrock is available to you. This is the easy part; insulating the walls without trapping vapor and getting mold or termites will be trickier. But as long as your roof has good overhangs, you should minimize direct solar gain, and you probably need free airflow in hot weather anyway unless you can seal up the house and air condition it.
 
Glenn Herbert
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You mentioned the ineffectively-installed reflective insulation; you might benefit from installing a layer of that under the roof sheathing before insulating with styrofoam, so you have a continuous airspace below it and get the reflective benefit. The reflective surface facing down will not get dust settling on it and reducing its effectiveness.
 
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Location: Arkansas Ozarks zone 7 alluvial,black,deep loam/clay with few rocks, wonderful creek bottom!
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Just wondering if styrofoam is an appropriate material for the 'natural building' forum? 
 
pollinator
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Location: Cincinnati, Ohio,Price Hill 45205
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Jay has some good insights on breathable but water resistant  buildings, hopefully he will notice this thread.
I believe he has suggested borax treated cardboard as insulation.
Borax fights pests and fire.
Screw some furring strips down over thick layer of cardboard, sheath over that.
Maybe sheath the house in hardboard?
Hardboard is cheap, durable and pretty environmentally friendly, being made from woodfibers,without glues.
It's the stuff pegboard is made of.
The gap between the card board and the sheathing will keep rain away from the insulation, and allow room for everything to dry.
It's kind of a bootleg rain screen.

If your windows really can't be replaced, maybe they can be reglazed,and a second larger window framed to cover the first.
Open new bigger window to get to the older smaller one inside.

Add a ceiling back in,something that can hold more cardboard insulation.
Run duct along the underside of the metal roofing.
In wintee draw heated air down into the living space.
In summer, let the heated vent create a draft to promote airflow.
 
Glenn Herbert
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Judith - Mmmmyeah, I wasn't paying attention to what forum the thread was in Read whatever natural insulation you want for styrofoam; I'm not up on what might be available in Louisiana. I stand by the basic premise of starting with the roof for immediate results.
 
pollinator
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I have a farmhouse built very similar to yours. We renovated it, adding 2x4 framed walls to the exterior. The house was moved to my location in 1906, relocated here after a flood devastated the city.

The deconstruction allowed me to observe what they had done in previous generations. It was cool, going back in time a layer at a time.

The most recent thing was simply 1/4" wallboard nailed on the inside. Not so magical. But under that,  over the existing 1x12 interior/exterior wall, is where it got interesting. First layer was burlap nailed onto the walls with carpet tacks. Thousands and thousands of carpet tacks. Over this burlap was wallpaper,  to give a finished wall.

This was not unique to this house. Ive seen barnwood projects in my area, where they reuse the wood. I often see the 1x12s with carpet tacks in them. 

The only observation i saw in the ceilings was a suspended ceiling added. This added insulation and smaller cu ft of heated/cooled area. This was probably done in tbe 1970's or 80's. I added ceiling joists to the top creating an 11ft celing height which was then insulated. The suspended ceiling was between 7 and 8ft tall.
 
pollinator
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I'm in a completely different climate but I did a bunch of research and want to mention some principles before ideas of exactly what to use:

Houses suck: i.e.: your temp difference between inside and outside and the amount of transfer space between the two determine how much energy you need to maintain the temp you want.  So your leaky floor insulation is still helpful! Same if you inefficiently insulate your walls so that air/moisture can escape but just not as much.  Modern insulation people try for a complete seal, which is a bad idea on about any old house, even here.

Your biggest bang for buck is typically the roof and main wind direction.

Thermal mass can maintain a house at a temperature for like 24 hours.

Fires happen.  If you insulate with something flammable, you might end up with a lot less insulation and house.

____
Now for specifics:

If in summer you get any sun inside,  block that out.  I had heartache over that here, but it lowered our air conditioning bill to about zero.  If it's on the roof, try a fast growing non- house- eating vine or trees.  They will also help slow down that rain on the roof a bit. Radiant barriers (i.e. aluminum foil) slow heart transfer, but if it's hot or cold for days on end, they don't help.


To doublepane the windows, you can try shower curtains. Staple it to the top of the frame and attach a wood dowel to the bottom end so you can roll them up when you don't want it.  These cost about $1 each.

Another simple insulation is blankets.  Good moving blankets cost about $10 new.  I wonder if you can ask for damaged ones from a moving company.  They are used by those who make music as sound insulation and can be cut to curtains or hung as tapestries.

As for thermal mass, cob is great for that, but so heavy! Can your floor support it?

Wood is about as insulating as the rigid foam, so if you have access to wood planking, logs, etc. you could use that. A way to get it on the walls and yet not is to build cabinets with backing against your walls. Put the stuff you want to sit on towards the center of the house so you don't get the wall drafts.
 
Amit Enventres
pollinator
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Location: Ohio, USA
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Also remember that climate control really starts outside and works it's way inward- after all, isn't that where the temp you don't want comes from?

So, if you haven't already,  start with sun direction and wind direction.  See how you can manipulate how that hits the house to benefit your climate needs.  A berm (compensating for drainage) in the wind direction? Hedgerow? Wall? Shed? Etc. Last is pulling out the kindelling, in my opinion.
 
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I live in Mobile, AL and we share rainstorms.  Just bought a 40 year old house that looks like it was remodled by  someone who knew how to use tools, but didnt know how to use them to remodel a house preoperly.  I have more work cut out for me undoing stuff that's wrong and caused water damage than I have time for really.

But I know that here on the swamp coasts where we live, anual rainfall rivals the likes of Seattle, so moisture is a formidable enemy for wood even on the short-term.

I feel like air space that allows for flow is your best bet, so if you can just get sheets of anything up there at the rafters and sealed it would go a long way to cutting the noise.  Maybe check at cabinet shops for scrap 1/4 inch luon.  Its thin plywood sheets that cost $16 for for the full 96x48, but cabinet shops ought to  have a good deal of scrap piled up and willing to let go for much cheaper per square foot.  If I were to find enough scrap for the whole ceiling, it would look absurdly patch-work.  I would probalby want to seal all the seams and then try to apply a clear coat or paint coat perhaps.
 
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Location: Hudson Valley Zone 5b
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Start by spending a day or two reading this website: 

https://buildingscience.com/

They have many great articles that explain proper wall construction in different climates. How to get vapor barriers and insulation right...

To me, the two most important concepts to figuring out "the best bang for the buck" are (1) how r-value works; and (2) how heat travels.

R-value:  when you double r-value, you cut heat transfer in half. So for example let's assume a wall has an r-value of 1, and you're loosing 100 "units" of heat, and every incremental r-value of one costs one dollar.  if you insulate to an r-value of 2, you spend one dollar to cut your heat loss by 50 units. Doubling the insulative value again to r4 will cost an additional $2 and will reduce heat loss to 25 units. R8 will cost another $4 and reduces your heat loss by 12.5 units. R16 costs an additional $8 but only reduces heat loss By 6.25, etc. etc. As you continue to add insulation, you quickly will spend huge sums of money to achieve insignificant incremental energy savings.  By far the biggest incremental energy saving per $ spent occur at the beginning of the curve.

The popular misconception is that heat rises.  Hot air rises but heat actually radiates in all directions. It flows through your floor as quickly as your walls and ceiling assuming the same insulative properties and heat differential between interior and exterior.  There is a separate reason in the north to increase insulation to a ceiling - ice dam prevention - but not because of excess heat loss.

In my house, adding one inch of eps under my basement slab was by far the best "beyond code"  decision I made. That's because I was taking the r-value up from approximately r-1 (the r-value of an inch of concrete) to r-5.5 (r4.5 per inch of eps plus the concrete). Resulting in a greater than 75% decrease in heat loss.  In comparison to increasing the wall or ceiling insulation from code minimum of r-21 (where the vast majority of efficiency gains had already been realized) to some greater amount, there was no comparison in terms of roi.

I would guess that the r-value for all the walls and ceiling in your house is very low, perhaps as low as r-1 or r-2.  I would therefore guess that the best bang for your buck would be to uniformly throughout the house get the levels up 4-8 r-value points by for instance putting in an inch or two of eps. That would be better than concentrating on one area such as the roof. If you're good with excel you could model it out but if I'm understanding your situation that seems intuitively correct.

 
O. Donnelly
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Location: Hudson Valley Zone 5b
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This document provides a very good starting point to understand how wall assemblies should be constructed in different climates:

https://buildingscience.com/sites/default/files/migrate/pdf/RR-0412_Insulation_Sheathing_Retarders_BFG.pdf

This is a good starting point on how roof assemblies should be constructed:

https://buildingscience.com/file/3187/download?token=NbH3Z0RN

You basically have a blank canvas. Your house is akin to a stick built house under construction that has dimensional lumber and osb sheeting but no additional wall assembly components yet installed. You can build inward and outward from that point by adding siding, air and vapor barriers, insulation, etc according to the needs of your climate and you budget. And consider that even though that might seem daunting and expensive, it may have a very rapid payback given how extremely energy inefficient your house is.

The most important thing to remember is to prevent moisture from being trapped inside wall assemblies and in contact with organic material (wood, paper, rice hulls, cellulose, etc) by improper placement of vapor barriers or the dreaded double vapor barrier (vapor barriers on both sides of the wall assembly).


My guess is that in your climate you're going to want walls to dry to the inside, so you'll want a moisture barrier towards the outside of the assembly and no barriers on the inside (oil based paint, wallpaper, etc).  Probably something like siding - a couple inches of eps or othe rigid foam insulation (insulation air and vapor barrier) - existing barge board - new optional 2x4 internal framing filled with high density blown fiber glass insulation (inert, non-toxic, won't absorb water or foster mold growth, good value for additional r-value) - drywall - latex paint - artwork.
 
pollinator
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I keep thinking of a post on here from someone who had a cabin with no insulation and I think open chinks too, and they put a bunch of stones around their wood stove or some other thermal mass and that made it more comfortable than the neighbors' cabins who insulated.

The thing about heat radiating down into the floor is interesting--since you'd probably have to open up a space and put a rocket mass heater on the earth itself, water and all, if you wanted to do that.  And any insulation you might think about putting under all that mass would get squished into fairly irrelevant status.  Wood might be the best you could do--it's better than nothing.  Char the bottom of the wood to prevent rot.

But the earth under your house will also serve as a thermal battery, that's the thing I don't yet really get but Jon Hait talks about this, and Paul Wheaton talks about it in the wofati design (keeping annualized thermal heat in the soil under and around the house in the winter, and the cold staying into the summer.)

Oh, my disclaimer, I'm only repeating others' ideas here, not talking from my own experience.
 
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I haven't tried this, so I may well be wrong,  but I've often thought that a grow box up on the peak of the roof planted with some fast growing, non gripping vine (like sweet potato,maybe) would go a long way to cooling a house.  (I thought of a watermelon vine, but the image of a 80 lb melon rolling off the roof is both frightening and hilarious, so melons are probably a bad idea)

Potential problems I see are:
1 the weight of soil and vine.  Many old houses were built by guess and by damn with whatever was handy.  Yours might not like the weight.  It wasn't built for a snowload, but it has held up against hurricanes, so it has some strength

2. Need to water what is essentially a long raised bed.  A wicking bed might give some relief here, but you would need be aware.

In winter, if the house is a little cold, I favor warm clothes and thick socks.  Many people seem to want their 'style' irrespective of the weather.  My 19 year old loves hoodies, which are fine in the winter, but it's 90 to 100 degrees right now with high humidity.  Adapt!!!  I also like 2 liter bottles full of shortish water under a blanket for tv, reading or bed when the house is cold.
 

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