[bkimbark1]

Hi everyone,

I just bought a house and am making some initial plans for finishing my basement and I figured a good place to start would be with adding some insulation. Along the top of the concrete foundation walls there is a gap where some plumbing pipes (which I need to secure) run parallel to the joists, and on the walls perpendicular with the joists, are pretty much empty gaps. Can/should I add insulation into these areas before finishing? What options do I have as far as insulation choices?

Also, I've been doing some reading about adding insulation to concrete walls. Most articles I have read have said to first check for any moisture first. The concrete walls are painted white but I'm not sure if they are a waterproofing product or not. Either way, there is not any signs of moisture, so I think I am OK to insulate.

What is the best approach for insulating along my concrete wall? Foam insulation, and frame on top of the foam? Frame directly on the concrete and add insulation between studs?

I am attaching some pictures of the space. I appreciate any guidance you all can offer.

Thanks,

Brian

 

[Nealtw]

Nothing painted on the walls will stop water from coming in so if the paint is not blistered or pealing, that would be a good indication that you don't have leaks unless the paint is so new it is too early to tell.

I would move the water pipes in to inside the next joist space, any repairs above the new wall would be a nightmare and the further away from the cold the better.



There are a few ways you can finish the wall.
Depending on where you are and how much insulation is needed.

Some people just do foam board and drywall
Some people do a foam board and a 2x4 wall
We build a wall 1" away from the concrete wall and insulate that.

yes the rim joist on top of the wall should be insulated if nothing else is, that effects the floor upstairs. A tight fitting rock wool would be best for that.

You can use foam board but it needs to sealed behind drywall unless you are going to drywall the ceiling soon.

Any time you add insulation, you are leaving the other side cold so blocking house air from getting to that cold surface is imperative.



How much room do you have under that beam, you would like to have 80" or more.

 

[Bud9051]

Hi Brian. Add a nearby big city to your profile so we will better know your climate.

Painting a basement does little to improve moisture issues other than hiding any evidence of the problem. The consequences of discovering a moisture problem after a nice renovation can be expensive and moisture is always there, it is what makes your grass grow.

Here is a link on basements to get you started.

Bud

 

[bkimbark1]

Nothing painted on the walls will stop water from coming in so if the paint is not blistered or pealing, that would be a good indication that you don't have leaks unless the paint is so new it is too early to tell.

I would move the water pipes in to inside the next joist space, any repairs above the new wall would be a nightmare and the further away from the cold the better.



There are a few ways you can finish the wall.
Depending on where you are and how much insulation is needed.

Some people just do foam board and drywall
Some people do a foam board and a 2x4 wall
We build a wall 1" away from the concrete wall and insulate that.

yes the rim joist on top of the wall should be insulated if nothing else is, that effects the floor upstairs. A tight fitting rock wool would be best for that.

You can use foam board but it needs to sealed behind drywall unless you are going to drywall the ceiling soon.

Any time you add insulation, you are leaving the other side cold so blocking house air from getting to that cold surface is imperative.



How much room do you have under that beam, you would like to have 80" or more.

Thanks for the information. I’m unsure about how I’m going to finish the ceiling so I’ll probably just stick with the rock wool.

The central beam you see with the lally columns comes down to 6’2” clearance. (I made another post recently about that) the ceiling height to the joists in the rest of the basement is about 7’.

 

[Nealtw]

Thanks for the information. I’m unsure about how I’m going to finish the ceiling so I’ll probably just stick with the rock wool.

The central beam you see with the lally columns comes down to 6’2” clearance. (I made another post recently about that) the ceiling height to the joists in the rest of the basement is about 7’.

I thought that might be the same basement. I had suggested raising the beam but you could just raise one section so you have height in an access area.

 

[bkimbark1]

Hi Brian. Add a nearby big city to your profile so we will better know your climate.

Painting a basement does little to improve moisture issues other than hiding any evidence of the problem. The consequences of discovering a moisture problem after a nice renovation can be expensive and moisture is always there, it is what makes your grass grow.

Here is a link on basements to get you started.

Bud

Thanks for the link and information. So if I’m reading this right, based on this post, one viable option is to use rigid insulation (still unsure if there’s a difference between using semi-permeable vs semi-impermeable) with wood framing on top of it and unfaced fiberglass in the area between studs.

Should I look into additional vapor control outside of this, or maybe just tape the joints in the rigid insulation to prevent moisture? If I do go for more moisture protection, what options do I have?

Also, I live about an hour North of NYC. So winters are pretty cold.

Thanks,

Brian

 

[EMRYS]

The rim on top of the foundation is a good place to start. For one house I worked on I cut 2" thick extruded foam to fit tightly in each bay (beware - some size differences). I applied acoustical sealant around the joist/rim board edges then 2 slabs of foam; more sealant and then a tight fitting piece of gyproc for fire-proofing. Note: some roofing companies sell 2nd hand slabs of this foam - not pretty but it does the job.

Recently Habitat for Humanity were selling foam in a can for $1 Cdn !! Bought 40 for my next rim joist job. It will be faster and I've got HEATING DUCTS to insulate !

In cold climates insulating basement walls to the floor is essential but the US & Canada differ on the use of vapour barriers. The CMHC website offers well researched advice but check you local codes.

 

[mzgloves20]

The rim on top of the foundation is a good place to start. For one house I worked on I cut 2" thick extruded foam to fit tightly in each bay (beware - some size differences). I applied acoustical sealant around the joist/rim board edges then 2 slabs of foam; more sealant and then a tight fitting piece of gyproc for fire-proofing. Note: some roofing companies sell 2nd hand slabs of this foam - not pretty but it does the job.

Recently Habitat for Humanity were selling foam in a can for $1 Cdn !! Bought 40 for my next rim joist job. It will be faster and I've got HEATING DUCTS to insulate !

In cold climates insulating basement walls to the floor is essential but the US & Canada differ on the use of vapour barriers. The CMHC website offers well researched advice but check you local codes.

This is the standard where we are. Just did a 2700 sq ft basement seal rims as you stated and foam panel on walls. Maintains 65 degrees with no help form hvac system needed.