Often asked: How To Insulate A Basement Wall With Rigid Foam?

Do you need a vapor barrier with rigid foam insulation?

Rigid foam insulation is it’s own vapour barrier in this application, so you don’t need to use the poly. Just make sure you tuck tape all the joints. Yes, you can go right over your existing blown in insulation with batt insulation, just make sure you butt the batts up tight against one another so there are no gaps.

What rigid foam insulation is best for basement walls?

When used for the interior or exterior of foundation walls or below-grade basements, this type of insulation can also improve insulation while also avoiding issues with moisture buildup or leaks. Foam board made from polyisocyanurate (polyiso) generally offers the best insulation capacity and 6.5 per inch.

How do you cover rigid insulation on a foundation wall?

Insulation Protection



The most common approach is to apply a stucco-like “parged” finish with a surface-bonding cement. These finishes range from a thin paint-on coating to a thick acrylic-modified mortar applied over hardware cloth or metal or fiberglass lath.

You might be interested:  How To Make Moss Wall Art?

What is the best insulation for basement walls?

Spray foam is probably the best possible insulation material for basements and damp areas. Closed cell spray foam is perfect for locking “out” the water vapor that inherintely wants to migrate from your damp basement walls to your finished basement rooms.

Which side of foam board insulation faces out?

If you’re wondering whether to put the foil side of foam insulation board shiny side in or out, consider whether you want to make the space inside warmer or cooler. If you want to make the space warmer, the foil should face inside so it can reflect radiant heat back into the room.

Should I use faced or unfaced insulation for basement walls?

Place faced insulation between the studs with the vapor retarder facing the interior of the room. For the band joist, use unfaced cut-to-fit pieces of insulation and place them snugly into the space. Cover with an interior finish material, such as drywall, as soon as the insulation is in place.

Can rigid foam insulation be left exposed?

Q: Can FOAMULAR® be left exposed in interior applications? A: No. To comply with building codes, all foam plastics must be covered with a 15 minute thermal barrier.

What is the cheapest way to insulate basement walls?

  1. Now that I think about it, the cheapest way to do this might be to spray the walls in one inch of either closed-cell spray foam or XPS (depending on your wall’s smoothness), and then cover that in rigid mineral wool boards.
  2. Actually, some of this goes against modern building science recommendations.
You might be interested:  Readers ask: How To Make A Jo Aikido?

What is a 15 minute thermal barrier?

Occupied and Unoccupied Spaces



The 15minute period is thought to typically be a sufficient time for occupants to escape from a building before they can be trapped, or overcome by smoke from burning wood, plastic or other construction and finish materials.

Can you put rigid foam insulation between studs?

Even with its flaws—namely, its inability to perfectly mold to the bays between the studsrigid foam insulation will be a better bet than no insulation. Using low-expanding spray foam sealant to seal those gaps further increases rigid foam’s insulating properties between studs.

Is it OK to not insulate basement walls?

Impervious insulation is always an excellent idea for basement walls, but it’s absolutely essential where the floor joists of the level above meets outside walls along the edges of a basement ceiling. But this barrier can never work because it can’t be properly sealed around all those joists.

Do I need a vapor barrier on my basement walls?

It provides the best coverage and R-value and and functions as a moisture barrier in and of itself. But if you use fiberglass insulation batts, then a moisture barrier will prevent water and moisture from entering your walls and creating mold and mildew.

How do you insulate basement walls after framing?

Install two inches of rigid insulation board directly against concrete. It is easiest to attach it to the wall with a couple of concrete nails or even some adhesive while you frame walls. Frame an interior 2×4 stud wall at 24 inch centres, pressed tightly against the foam panels.

Written by

Leave a Reply