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JohnGarland
Insulating old home with no vapor barrier
JohnGarland

I am interested adding HVAC and insulating an old family home built in 1828 in West Point Georgia. The house is one level and sits on brick piers. On the outside there is wood siding. On the inside there is wood lath cover with plaster. There is no other vapor or air barrier between the inside and outside. The bottoms of the walls are open to the elements. For the last 180 years the natural air movement through the wall has keep rot from developing. I am very concerned that if insulation is added, coupled with condensation from the heating and cooling, that moisture problems will develop in the walls. I don't want to remove all the old siding which is only slightly less dense that iron. I thought that doing poured open cell foam in the walls would be a good idea except for the potential moisture issues. Can I insulate this home without setting up a problem that will destroy it?

goldhiller
Re: Insulating old home with no vapor barrier
goldhiller

First question; Is there sheathing under the siding? If so.......how thick?

If not......how thick is the siding? More description of the type of siding might also be helpful.

Pics are always nice and frequently helpful.

pomer
Re: Insulating old home with no vapor barrier
pomer

open cell will let the moisture in you would need closed cell

JohnGarland
Re: Insulating old home with no vapor barrier
JohnGarland

No sheathing at all. The siding is composed of horizontal wood clapboard. Each piece is about 7/8th of an inch think.

Closed cell foam would be good, but I think that would require the interior plaster and wood lath to be removed. I am not aware of a pourable closed cell foam that could be poured through holes in the interior walls. I would like to avoid ripping out the interior walls if possible.

RyanB
Re: Insulating old home with no vapor barrier
RyanB
JohnGarland wrote:

Closed cell foam would be good, but I think that would require the interior plaster and wood lath to be removed. I am not aware of a pourable closed cell foam that could be poured through holes in the interior walls. I would like to avoid ripping out the interior walls if possible.

I have the same problem, i am looking into Closed cell foam from www.tigerfoam.com
it seems to be designed for just your (our) problem. it creates a vapour barrior, seals drafts, as well as excellent insulation (r7 per inch they say). I am interested to hear what others think of it...

nhartwig
Re: Insulating old home with no vapor barrier
nhartwig

I'm in a similar/different situation. My 82 year old aunt lives in Orange TX and her home was recently flooded during Hurricane Ike. Having gone through Hurricane Katrina myself in Mississippi three years ago, I got in a soon as the authorities opened the roads and got all the carpeting cut out, generator cranked up and air conditioning running to dehumidify her house. While mopping up mud and using PineSol and following up with Scott's Liquid Gold Mold control everywhere, we found that the flooring consisted of two types. One, old full dressed lumber 1x6 decking that "had" a foam cushion with carpet over it. The other is 1x6 full dress lumber with linoleum over it. The house was built in the 1930's and has full dress 4x6 sill beams that sit on concrete blocks 16 inches above the ground. There is full ventilation under the house (ie no crawl space) and partial skirting. There is no vapor barrier above or below the wood flooring where the carpet was. I assume the adhesive for the linoleum acts as a vapor barrier in the rooms with linoleum (kitchen, bath, & laundry room). The floor gets pretty chilly in the winter time too. I would like to hear from the experts on how to provide a vapor barrier and insulate this wood floor that is totally open underneath.
Thanks,
Neil

pb808
Re: Insulating old home with no vapor barrier
pb808

I am exploring foam insulation options for an 1890 home. So far I have found a few closed cell pour foam insulation companies. usa insulation http://www.usainsulation.net/about-us/
tripolymer
http://www.tripolymer.com/tripolymer/index.html
airtight insulation http://www.airtightinsulation.com

I am in process of getting prices now. closed cell seems like the correct way to go.

foammaster
Re: Insulating old home with no vapor barrier
foammaster

yes!!! you can have a "pour in" or "injection foam" installed that will insulate and stop your moisture problem. there is no need for a vapor barrier if you use Tripolmer foam. with the insulation in will stop the condensation problem. to really help you can have someone spray polyurathane on the underside and keep your floor warm or cool. i can get you in contact with a dealer in your area.
justin
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Gi
Re: Insulating old home with no vapor barrier
Gi

Lessons learned by a novice after hours of googling:

1. "Closed cell" relates to foam made from polyurethane, which is made from petroluem, so manufacturing the stuff is not enviromentally friendly.  It can be toxic, give off gases, and is subject to shrinkage. Hard pass from me.

2. Fiberglass has a lower R-value (see #4) than cellulose, which is cheaper than fiberglass.  Pass.

3. Cellulose is recycled, non-toxic, economical, resistant to: fire, insects, rodents, and most importantly DOESN'T REQUIRE A VAPOR BARRIER! wHOOOhOOO [1]! Cellulose options: blow/spray(if wall cavity is open), pourable (to fill tops of wall cavity), or batt (for hard-to-reach areas that can't be accessed with the blow-in product).  The bummer with pourable is that it comes out of the pack compact, so it needs to be fluffed [2].   The process isn't as terrible as I thought if you have a small area to insullate...see YouTube reference [3].

4. "R-value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another. As a benchmark...an inch of blown cellulose in an attic has an R-value of 3.2 - 3.7". This site has really helpful charts to determine what R-value you need depending on your climate and what part of the house you're insullating [4].

5. According to the first table of [4], I need an R-13 to top off my walls in my 1905 Minnesota home.  

     FOR BATTING: The second table in [4] shows that cellulose (wall) R-value per inch is 3.8, so a 3.5" insullation product depth will get me to 13.3 (3.8 R * 3.5" = 13.3 R-value result, which is what I needed...R-13).

     FOR POURABLE: "INSULMAX® insulation can achieve any R-Value a - from R-13 to R-60" [5]. The "Coverage Area" tells us that if I'm after an R13, I can spread one product bag across 85 sq ft.  

I hope this post saves someone a few hours of "fun" insulation research ;) .

[1] https://www.cellulose.org/HomeOwners/AirVaporBarriers.php

[2] https://www.homeownershub.com/maintenance/cellulose-insulation-without-m...

[3] https://youtu.be/S89qGnhd2m4?t=43

[4] https://www.greatdayimprovements.com/insulation-r-value-chart.aspx

[5] https://www.menards.com/main/building-materials/insulation/loose-fill-in...

John
Re: Insulating old home with no vapor barrier
John

From my research, you need to have an air gap between the exterior walls and the insultion, otherwise the moisture will cause the exterior paint to peel over time due to an inability for the siding to dry.

For spray foam (always closed cell), you should first put a layer of Dorken Delta Dry in the stud bay, with Dorken Delta Vent over it.  The Delta Dry creates the air gap, and the Delta Vent prevents the spray foam from filling that air space.  See the video by Matt Risinger titled "How to Insulate When The Back of The Siding is Exposed".

For 1.5" to 2" XPS foam board, you can repeat the Dorken Delta Dry & Delta Vent layer, or put 1x1 vertical (floor to ceiling) strips of wood in the corners of the stud bay against the outside wall.  When you place the foam in the bay the Dorken (or 1x1s) will prevent the board from pressing against the outside wall, thus creating a 1" air gap (hint: using the Dorken method will allow you to use thinner foam board because it will prevent the board from flexing).  Then use closed cell foam spray (in the can) to seal around the edges of the foam board.  It's also recommended that you "extend" the studs by attaching 2x2s to them (vertically), which will allow you to place rockwool over the foam board.  See the following article (and attached image) for details: Insulating Walls with No Sheathing.

At least that's what I've learned so far.  Neither of these methods address if this is the method to use if your exterior is stucco, which is my only question.  I've also read that an air gap is no longer needed, but I can't find that reference.

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