Insulating a concrete block wall?

[jforbes]

Hi! We're in the middle of a kitchen remodel. After removing the drywall over an exterior wall, be discovered that the wall is made of concrete blocks. My question is, there was no insulation between the exterior wall and the drywall - is this normal? There was no "framing", only 1x3 furring strips which the cabinets and drywall attached to. We are replacing the old furring strips with new 1x3's (and the cabinets have already been ordered so we have to stick with 1 inch thick furring strips or it will mess everything up). My question is - is it common to NOT insulated a block wall? Can we insulate it or is it not necessary? Is there such a thing as 1 inch thick insulation (since that's all the room we'd have to work with)?

FYI - we just bought this house 1 month ago, so we haven't really had a chance to learn how well/poorly insulated the house is. We live in the Philadelphia area so we get a pretty good mixture of hot summers and cold winters.

[giddonah]

more insulation can't hurt. (unless it really messes up the load calculations for an AC unit and causes the unit to then be oversized for the house). Barring central air though, adding insulation is a good idea. I'd check out foam boards. You can cut them to fit the spaces fairly well, and will be much easier to work with than fiberglass. Blown in cellulose is probably overkill for a small project.

[bkrahmer]

The best sheet insulation is polyisocyanurate. It's the yellow stuff that usually has aluminum foil on one or both sides. An inch of that will help quite a bit.

[jreid]

I'm no expert on insulation and I bow to most (well I haven't disagreed with any of them yet) of the experienced guys on this forum. I would check out buildingscience.com. I followed their recommendation on insulating my basement before finishing and the space is very habitable in the summer. It does not feel like a basement anymore.

The pink foam board found at HD is good stuff. Pricy, but 1" will get you R-6 I think. You can just glue it to the wall with liquid nails foam adheseive. You'll want to seal the joints with Tyvek style tape and also tape over your furring strips. This approach will provide a thermal barrier and an air barrier. Use the spray foam at the top and bottom to get a good seal too.

An important question to ask is what's on the other side of the concrete block? It needs to be sealed with Tyvek or something to keep the water out. Concrete block will leech a lot of moisture and condensation in the middle of the block (assuming the hollow kind) will drain out at the bottom unless properly installed with weep holes. You don't want that getting into the house or behind the wall. If you saw any eflouresence (white chalky stuff) on the block, I would dry-lok the wall before insulating.

I learned a lot of this at buildingscience.com. Check them out.

[rbisys]

Greetings,

Ck the "NT" radiant barrier material (RB) from fifoil.com.

I have done basement walls with this material and it is easy to install and is a excellent VB too.

Although RB do not have a "R" value, they reflect not resist, they will give you a much higher insulation value and you will not have condensation as you can with foam or other insulations in this type of application.

RB are about 97% eff, as to about 20% for foam.

[gamel]

Insulated concrete blocks can accommodate many walls in a home. Their cores are filled with insulation (except for those cells requiring structural steel reinforcing and concrete infill), which raises the average wall R-value. The better concrete masonry units reduce the area of connecting webs as much as possible.Some block makers coat polystyrene beads with a thin film of concrete. The concrete serves to bond the polystyrene while providing limited structural integrity. The most common group of ingredients are expanded polystyrene mixed with Portland cement, sand, and chemical additives. These make surface-bonded wall assemblies with a wall R-value of R-1 per inch thickness. Polystyrene inserts placed in the block cores increase the unit thermal resistance to about R-2 per inch.

[onerenohome]

You should insulate your concrete wall... polyisocyanurate is a good choice to go with, like bkrahmer suggested.

[biglumber35]

If you use XPS (extruded polystyrene) that is atleast 1-1/2" (blue or pink colour) and you don't need vapour barrier. Glue the XPS to concrete wall tuck tape all joints and use spray foam at the top and bottom of wall and in the corners will creat an air tight seal. the 1-1/2" product is shipped lapped to accept 1x4 strapping and then drywall can be hung

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[torontob]

Hi Guys,

First post here. I have a stupid question I guess. We have a newer house (5 years old) and the basement is unfinished. I am looking to put up few drywalls to make a small room inside the basement. I have bought some Baily metal studs and tracks for the purpose. I have also put some non-flamable insulation between the wooden joists on the ceiling. However, there is some poink insulation material that is already on the top half of the walls around the basement. The insulation is held in place by a vinyl that says, "Polytarp" on it. So, should take off the vinly and the pink insulation, do the Baily studs and tracks and then put the insulation inside the 16" studs? or do I just lean the stud against the basement walls against the insulation that is already in place on top half of the walls?

Here is a picture of the material that I am talking about:

a2billing2asterisk.googlepages.com/IMAG0048.jpg

Your input is much appreciated.

[roklin]

Concrete block walls for houses and other buildings were insulated with foamed resin paneling around their exteriors below ground level. Such insulation paneling was not extended above ground level, because the paneling could not withstand the harsh environment ground.

[bighammer]

i would like to see a foam material used directly applied to the concrete block leaving a 1" gap frame a 2"x4" wall and insulate with a vapor barrier. using just foam I have ran across problems with moisture/condensation, due to heat and cold transfer.

[Stretch5]

I have a very similar situation so i figured i would throw up a post instead of a new thread. My question is my house is brick with block walls and do i still have to be worried about condensation as much. I know that in a basement i do but wasn't sure about above ground.

[Steve Gordan]

Concrete block insulation is typically installed for new home construction or in homes undergoing major renovation. Since installation involves masonry skills, it's best to have a certified cement mason do it.When using masonry blocks for a foundation wall, filling the block cores with high-pressure foam works better than most poured-in insulations, like polystyrene beads or vermiculite or perlite pellets. For more ideas have a look on it.

[AaronB.]

Is tis block wall underground?

Is this an insulated block?

[ICF Construction]

Use InSoFast to insulate your concrete walls. I use it every chance I get.

[milhome1]

Use polyisocyanurate - one inch sheet - it will make a significant difference given the limits you are under.

[carlton]

i have a problem i bought a house that has concret block walls there is no insulation between the exterior wall and the drywall. i wanna the put 2x4 and put insulation but someone told me that may cause condensation. can that b posible?
Another thing is that the humidity in my house is too high thats why i want to have the insulaton put on cuz my exterior wall sweats a little bit and i growing mold .. can anybody please help me with that..please if anybody have an idea mail me to artogdl@gmail.com thanx..

[darcym23]

Hi Guys,

First post here. I have a stupid question I guess. We have a newer house (5 years old) and the basement is unfinished. I am looking to put up few drywalls to make a small room inside the basement. I have bought some Baily metal studs and tracks for the purpose. I have also put some non-flamable insulation between the wooden joists on the ceiling. However, there is some poink insulation material that is already on the top half of the walls around the basement. The insulation is held in place by a vinyl that says, "Polytarp" on it. So, should take off the vinly and the pink insulation, do the Baily studs and tracks and then put the insulation inside the 16" studs? or do I just lean the stud against the basement walls against the insulation that is already in place on top half of the walls?

Here is a picture of the material that I am talking about:

a2billing2asterisk.googlepages.com/IMAG0048.jpg

Your input is much appreciated.

i would suggest not using metal studs in your basement as they will rust over time, i suggest using a product called bluewood, it is treated and is mold and termite resistant , if you do decide to use it make sure you paint the cut ends with the same treatment to retain the product properties and for your subfloor use drycore, it creates a barrier between your flooring and the concrete and allowes air between, also keeps moisture away from your flooring, not sure what you have in mind. Also get rid of the old insulation and what ever is holding it up there, there is no sence wasting the space. I suggest using a spray foam insulation, it is much better, it doesn't settle over time and in most cases you don't need a vapor barrier. Before finishing any basement you should make sure it is water proof. There are products available for application on your walls but hopefully in your house, being fairly new it should have a good weeping tile and membrane system in place. Also go with a mold resistant drywall, more expensive but worth it. I hope this information is helpfull and good luck. ps no such thing as a stupid question, make sure you use a foam gasket material under your walls to create a seperation between the wood and concrete, also keep your studs about half an inch away from the exterior walls to allow the spray foam to penetrate. had to edit, kinda had a brain fart, thought you might already know that, but just in case. thanks.

[Laserlad]

I had an issue with the previous homeowner's insulation efforts in my 'finished' basement. He had just slapped some fiberglass insulation up against the concrete. We seem to have pretty good drainage without moisture issues, but it seems to me they let their gutters clog for while, causing water to pour off the sides on one corner of the house - there was evidence of moisture damage. Ripped all the old crap down, cleaned it up and used some drylok, quick install foam panels etc