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-   -   Exterior walls need upgrade in insulation (http://www.diychatroom.com/f103/exterior-walls-need-upgrade-insulation-107448/)

xjsparky 06-12-2011 01:13 PM

Exterior walls need upgrade in insulation
 
I know this topic has been reviewed what seems like a thousand times, feels like I've read them all too. Anyways, I'm replacing the aluminum siding on our 50 year old house with vinyl siding. I've been trying to get our home up to snuff on insulation for a few years now. It is a 1500sqft ranch on a crawl space. Two exterior sides are brick and the other two, siding. Currently there is only a thin batting in the walls, seems to be a 1"-1 1/2" batting with tar paper face, maybe something they used in that era. The walls are extremely cold in the winter months, we live in Northeast Indiana, I believe it is a zone 5. By this table on the energy star website, http://www.energystar.gov/index.cfm?...sulation_table , I should blow in insulation and add foam sheathing. My thoughts on this are how well would the blown in work with the old sheathing in there, I don't know if it would be able to fill voids well enough, and the other is that I would like to avoid adding 1" sheathing and having to frame out windows, doors, etc. I keep coming back to the idea of removing all exterior sheathing and using expanding foam insulation only and new sheathing, wrap, siding. Any ideas, personal experiences, professional tips, would be GREATLY appreciated on the best way to continue.

Gary in WA 06-13-2011 10:57 PM

There is a video I saw on blown-in cellulose of a test wall in a garage online. A professional installer dense packed a wall with remnants of fiberglass faced batts and did a good job. The key is "professional" install, not with the limited box store (weaker) blowers. Then add your rigid foam outside to raise the dew point temperature for no sheathing face condensation: http://www.greenbuildingadvisor.com/...ally-necessary

http://www.buildingscience.com/docum...bout-diffusion

Gary

HomeInsulation 06-14-2011 06:13 PM

Hey xjsparky,

I've insulated exterior walls in a home by tearing off the sheathing and replacing it. It's possible for the walls of your home that are covered with vinyl siding, but the brick sides are really going to make it hard to get in there.

I only tore the sheathing off because of rot and water damage, not just to insulate. But I did insulate the wall cavities with foam insulation and air sealed everything off while I was at it. It's not that hard to do, especially on a ranch, but it's definitely a little crazy.

If you decide to do it, remember how much structural stability the plywood adds to your home. Without the sheathing, a strong windstorm can really do some damage. I'd remove and replace it in sections to maintain structural stability.

Personally, I'd trust the expertise of a professional cellulose contractor. GBR in WA, is right to say they can do a great job. And the dense packed cellulose insulation will increase your walls R-value and reduce air leakage.

They would be able to blow all of your exterior walls in one day. And you could spend your time and energy on the finer details of your exterior upgrade.

Good luck,
Corey

xjsparky 06-19-2011 10:48 AM

thanks for a couple of the tips. im still unsure of what i want to do. im not sure if professional quality insulation blowers are readily available for rent. if so i may take a shot at dense packed insulation and then foam on the exterior. is 1/4" accordian style foam board even worth the hasssle or should i just do 1/2". i've gotten quotes for professional dense packed cellulose at around $1.15/sqft. i might shop around a little more though. i'd love to save myself the hassle of doing it.

Gary in WA 06-19-2011 09:38 PM

I doubt you will find the professional blowers for rent that can handle the density required for dense pack cellulose, notice the prices here: http://www.karg.com/pdf/Presentation...Insulation.pdf

The 1/4" foam is added to help "level" the installation, not for R-value. Even 1/2" is a waste of money: http://hubpages.com/hub/Does-Foam-Bo...lp-Save-Energy

Minimum thickness of foam board: http://www.greenbuildingadvisor.com/...foam-sheathing

You want the sheathing warmer with more exterior insulation rather than colder (with more cavity insulation) for the dew point temperature rise, and follow the links here: http://www.greenbuildingadvisor.com/...ally-necessary

Gary

Perry525 06-22-2011 03:43 PM

Insulation.
 
The logic of insulation is that you want it as close to your comfort zone as possible.
This means on the inside of the walls, floors and ceilings!
Putting it on the inside saves:
Wasting heat on heating the buildings frame and solid walls.
Wasting heat on heating the spaces between the frame.
It uses less material and saves money.

The best way forward is to fill the spaces between the frame with sheets of polystyrene carefully cut to a tight fit.
Then to cover the whole of the inside with at least 3 inch thick sheets of polystyrene, tightly butted to keep the heat and the water vapor out of the walls.

Water vapor always moves from hot to cold, but three inch thick polystyrene provides enough insulation, to stop the "dew point" effect and keep the walls dry.

Do this and you will have a warm draft free home, that is very cheap to heat.

It also saves a lot of work and keeps the outside looking the same, no doors and windows to reposition.

HomeSealed 06-22-2011 09:35 PM

:eek:
Quote:

Originally Posted by Perry525 (Post 672114)
The logic of insulation is that you want it as close to your comfort zone as possible.
This means on the inside of the walls, floors and ceilings!
Putting it on the inside saves:
Wasting heat on heating the buildings frame and solid walls.
Wasting heat on heating the spaces between the frame.
It uses less material and saves money.

The best way forward is to fill the spaces between the frame with sheets of polystyrene carefully cut to a tight fit.
Then to cover the whole of the inside with at least 3 inch thick sheets of polystyrene, tightly butted to keep the heat and the water vapor out of the walls.

Water vapor always moves from hot to cold, but three inch thick polystyrene provides enough insulation, to stop the "dew point" effect and keep the walls dry.

Do this and you will have a warm draft free home, that is very cheap to heat.

It also saves a lot of work and keeps the outside looking the same, no doors and windows to reposition.


HomeSealed 06-22-2011 09:43 PM

Quote:

Originally Posted by xjsparky (Post 669944)
thanks for a couple of the tips. im still unsure of what i want to do. im not sure if professional quality insulation blowers are readily available for rent. if so i may take a shot at dense packed insulation and then foam on the exterior. is 1/4" accordian style foam board even worth the hasssle or should i just do 1/2". i've gotten quotes for professional dense packed cellulose at around $1.15/sqft. i might shop around a little more though. i'd love to save myself the hassle of doing it.

Dense packing really is not a DIY job imo for the reasons mentioned, however it can be done very effectively. There are a lot of variables involved, but in my area, the price that you were quoted is really good.. The "accordian style board" (fanfold) will do very little to insulate. It can be helpful, however, in preventing air leakage if installed properly (tight, taped seams, etc)... All of the recommendations by GBR and HI have been on point.


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