1820 house and wall insulation

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fraxinus

Feeling the Heat
Aug 3, 2007
341
coastal Maine
The main part of this two and a half story house was built circa 1820. There is no insulation in the walls at all. (Attic has been insulated.) Walls consist of cedar clapboards, full one each boarding boards, cavity, wooden lathing, 1 to 1.5 inches of plaster. The real problem comes with the wall construction. There are 8 by 8 inch corner posts, and 4 by 4 inch framing around the windows - that's it; no other wall studs. Because of this construction, the area from corner post to window framing is anywhere from 3 to 4 feet plus. I have consulted with two insulation contractors and one carpenter who has 30 years' experience with old houses. The consensus is that blowing in insulation from the outside would be useless as it would settle even more under my conditions than it does anyway. This is not a drafty house; I do, however, use 8+ cords of wood per winter and would like to reduce this amount as well as the wear and tear on my aging body. Tearing out the plaster walls and insulating from the inside is not an option. I'm afraid I already know the answer, but would be interested in any options for insulating from the outside I may not have thought of. Thanks.
 
I'm confused. Are they saying that blown insulation would do no good at all or are they saying that, in your situation, it's not cost effective?

I can see that it might not be as efficient in your walls as it would otherwise be due to settling but I can't see how it could be useless. How about doing the blow in in increments? If you blew in from the outside, plugged the holes temporarily, gave it time to settle, and then blew more in to top it off I don't see that the lack of framing would be a big deal. Sure, you'll use more insulation than the average home would but it would have to help.

My wall are standard framing but similar in that it's wood clapboard with wood lath and plaster. We plan on blowing insulation in ourselves next year. Seems like the uninsulated walls just radiate cold sometimes so I'd think anything in there would be a plus.
 
Thanks for your reply, Peggy. The issue is mostly cost effectiveness. The long walls are 22 feet by roughly 16 high. There are no constraining bays formed by wall studs as in more conventional framing, so blown in insulation would, according to the people I talked to, settle at least twice as much as normal resulting in most of it eventually winding up at the bottom of the wall cavity even if done bit by bit. The weight of the insulation would cause it to compress much more than usual.
 
Here is a thought. What if, after you blew in the insulation near the bottom, you squirted expanding foam insulation into the hole before you plugged it. Move up to the next level of holes and repeat until you get to the top of the wall. if the holes were close enough together the foam insulation would reduce the settling. This is only a theory; I have never tried it. My house has lath and plaster on normally spaced studs and blown in insulation that has seen very little settling. I think that the siding nails that extend into the wall cavity prevent the settling.
 
At the risk of getting in trouble...how about posting that to the ASK THIS OLD HOUSE show on TV. You know the one that used to have Bob Viela but now has some younger red haired kid. I bet your situation is unusual enough to merit consideration.
 
A half-insulated wall will still lose less heat than an uninsulated wall.
 
It won't settle away to nothing. You'll get some insulation in there and a 50% fill after compaction can be filled to the top later. Or even a 50% fill is a 50% fill.

The glass is half full.
 
The spray in foam idea sounds a little off the wall, pun intended, but it just might work! If you blew in say enough insulation to fill 3 vertical feet and then drilled a horizontal line of small holes just above that level and shot foam in and gave it a little time to expand and set before shooting another layer I think it just might work. Of course, you'd have to be pretty precise about the amount of insulation and foam shot in so that you wouldn't end up with large gaps or have the foam compress the insulation. Hmmm....interesting problem.

If there's no vertical framing what the heck are your clapboards nailed to? Do they "float" from window to window only nailed on each end? How about removing enough clapboards to install a horizontal block or two in the walls from the outside?

Is it possible to just spray foam in the entire thing? Do they do that? I've only ever seen them use the spray in walls before the sheetrock is installed. Is it possible to use the stuff in a closed wall and not have it cause problems?
 
Peggy - Thanks for your interest. Years ago, there was spray in foam that could be applied from the outside, but the product was banned because of its formaldyhyde content. I know two people who had it done and were pleased with the results. Currently available foam type products can only be applied from the inside and are really designed for new construction, as far as I know.
The clapboards are nailed mostly to the boarding boards which are at least 5/4 inch thick. The floor joists, by the way are 10" diameter cedar logs with the only the top surface flattened, the sills are 12 x 12 inch spruce heartwood ( both as solid as the day they were installed), and the roof uses horizontal cedar purlins with the roof boards running from peak to eave rather than horizontally. Floor joists and purlins are inset and held with wooden pegs as in timber framing.
 
Hi,

I insulated my 1880 house from the outside. It really wasn't that difficult, and my house is 2 stories and has "stud" framing at all different angles that I had to deal with. So, the lack of stud framing in your walls should make the project even easier. You will need at a minimum 2 people. I used the standard rolled up insulation with the paper backing, and the paper backing went against the inside wall (I know the orientation depends on location so ask at the store how to install). Buy the thickest insulation you think you can get in between the clapboards and interior wall, but not so thick as to make the task impossible. Here's how it is done.

1.) Remove clapboards at the top and bottom of the exterior wall. Just enough room to work is all you need. I only had to remove 2 at the top and 2 at the bottom
2.) Tie a slipknot around the top of the insulation; the insulation will bunch up some when you do this but it is okay
3.) Tie a slipknot at the other end of the rope and fasten around something heavy, but slender; like a hammer
4.) Feed the hammer fastened to the rope through the top opening you created by removing the clapboards. Have somebody at the bottom opening to receive the hammer and pull it through.
5.) Now stuff the insulation in through the top, while the person on the bottom gently pulls on the rope
6.) Person on top guides and stuffs the insulation while person on bottom pulls.

Now, with the lathe you may some snags to contend with. You may want to "line" the inside wall with plastic sheathing. This will prevent your insulation from getting snagged, and will also provide a slippery surface for you to slide the insulation against.

Take a look at the picture, to see how a couple of clapboards removed makes it pretty easy to stuff insulation in there.
 

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Actually, I was thinking of this as a DIY project. Buy the insulation from Lowe's and use their blower. I was thinking about the canned foam insulation, Great Stuff, to inject to form horizontal blocks for the insulation. I know that stuff is pricey but last year I found it at Big Lots for like $10 a case rather than the close to $5 a can it normally sells for so you might be able to find it cheaper with a little searching. For sure, it would take a LOT of cans and drive your cost up though! The up side is that with the straw on the cans you'd need only very small holes to inject it thru the outer wall.

Don't ya just love old houses? lol There's a challenge around every corner!
 
Thanks, Millworker. Your suggestion is one I never would have thought of. The difficulty I see is this: once the clapboards are removed, you'd also have to remove boarding boards. In order to have something to renail them to you'd need a pretty wide opening - from vertical supprt to vertical support. Not an insurmountable problem, but removing clapboards and boarding boards (and I have replaced more than a few) without cracking them is hard. I'm also not sure how I'd go about installing the plastic. It would seem doing this would be absolutely necessary to avoid snagging the insulation on the plaster that sticks out into the cavity between the lathes; putting in the plastic without tearing it on the abrasive plaster is a puzzler. I'm also not sure what the effect would be a plastic vapor barrier in this part of the wall. Also, what did you do about the vertical seams between lengths of insulation?
The whole issue of insulation in old houses is tough. They have lasted, as my old house carpenter friend likes to point out, precisely because they "breathe". Moisture, the enemy of all wood constuction, is not trapped when you have uninsulated wall cavities. Several years ago, the new owners of a 19th century house a block away had vinyl siding installed. The next owners stripped off the vinyl. The bottom four feet or so of every wall - lathe, stud, sills - was rotted and saturated with water.
 
Hello,
I have been doing cellulose insulation for about 20 yrs now. Until about 4 yrs ago I only did it along with the renovation work I was doing. I finally dove in head first and only do cellulose now. There are many experts in this cellulose business besides me. There is a ton of info on the internet. There is also a ton of negative info about cellulose on the internet, mostly from competitors.
First of all, do your own research. Get some estimates from reputable people. Learn to see thru the b.s that salesmen pitch. Cellulose has come a long way since the days of loose fill insulation. With todays equipment and installation methods, it wont settle if done properly. I have done many house's just like yours. We now use a method called "dense packing". (this method has been around since the 50's). On most jobs we insert a 1 to 2 inch diameter flexible tube up into the wall cavity from a hole drilled a foot from the bottom. We push the tube up as far as it can go.( if we hit an obstruction we drill above it). The cellulose flows in thru our high speed blower to the bottom and fills to the top. Then the tube is gradually withdrawn as more cellulose if forced in, packing it so tight if will never settle. The cellulose fills every void and nook and cranny. It virtually eliminates air infiltration and also acts a great sound barrier. The cost factor varies on the difficulty to access wall cavities. It could run as low as a $1.25 a sq. ft. to as high as $3.50 a sq.ft. Most of the foam products run at about $6.50 and above. At todays fuel prices, ANY insulation will pay for itself fairly quick. You can find all of the info in the world on the internet, just be carefull how you interpret it.

Mike
www.albanyinsulation.com
 
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