Do I need to insulate below grade? (2024)

Table of Contents

Do I need to insulate below grade?

Below-grade walls require continuous insulation (CI) with the correct R-value for basem*nt walls. Typically, builders install insulation (sprayed foam, foam board, and/or fiberglass) on the exterior of the wall, which helps insulate the whole house.

(Video) How to Properly Insulate a Basem*nt Wall: NO MOISTURE!
(Home RenoVision DIY)
Should I insulate below grade basem*nt walls?

Because of the risk of mold and other moisture problems, the insulation of interior basem*nt walls is very challeng- ing to do properly. Unless basem*nts have a very low risk of moisture potential, it is better to leave the walls unin- sulated on the interior to allow drying and reduce mold and mildew issues.

(Video) How to Insulate a Basem*nt | This Old House
(This Old House)
Do underground walls need insulation?

Underground spaces with a soil-facing wall require basem*nt wall insulation to protect the room from heat loss and moisture build-up.

(Video) How to Insulate Your Basem*nt: Part 3
(finehomebuilding)
What insulation to use for below grade walls?

Rigid foam insulations commonly used below grade include expanded polystyrene (EPS) and extruded polystyrene. EPS performs significantly different from XPS in terms of moisture, and much confusion exists about which one is better. Ultimately, it depends on how you measure it.

(Video) Vapor Barriers: Need one or not?
(Matt Risinger)
Does an underground basem*nt need insulation?

The Importance of Insulating Basem*nt Walls. There are a few reasons that basem*nt wall insulation is important and necessary. These range from energy conservation, to code requirements in certain areas. Regardless, having a properly insulated basem*nt should be a priority for homeowners.

(Video) Foundation Insulation Effectiveness: Basem*nt building science
(NDSUExtension)
Should I insulate unfinished basem*nt walls?

The fact is, an unfinished, uninsulated basem*nt can significantly decrease your home's efficiency and value. Just investing in basem*nt insulation can increase your home's efficiency, reduce stress on your HVAC system, and make your home more comfortable throughout the year.

(Video) Why Use RIGID Insulation board On basem*nt walls
(A Concord Carpenter / ToolBoxBuzz)
Do concrete basem*nt walls need insulation?

Your basem*nt needs wall insulation. Eight inches of uninsulated concrete has an R-value of 1.35ea, meaning a tremendous amount of heat is lost through uninsulated concrete walls. Any basem*nt used as a living space–or at least more than a large storage room–should be well insulated for comfort and energy savings.

(Video) Insulating a Floor Over an Unheated Space
(ROCKWOOL North America)
Do basem*nt walls need to breathe?

There is no need for concrete to breath from the point of view of the strength of the material. There will be moisture retained from the original mix and it is possible some are confused about the chemistry of concrete and think it needs to dry, but the truth is the complete opposite of that.

(Video) Slab-on-Grade Foundation With Concrete Stem Wall and Under Slab Insulation
(International Association of Certified Home Inspectors (InterNACHI))
What happens if no insulation in walls?

A lack of exterior wall insulation can lead to cold drafts coming through electrical outlets and light switches. These cold drafts contribute to high energy bills, as the furnace is constantly running. Filling the external wall cavity with insulation will help reduce the drafts depending on the material used.

(Video) Slab-On-Grade INSULATED Foundation - Part 1
(Matt Risinger)
Will insulating basem*nt make house warmer?

By insulating your basem*nt with spray foam, you're making it incredibly easy and efficient to heat not just the basem*nt, but your whole home. Spray foam does this by sealing up air leaks in the rim joists, and locking out the moisture in the foundation.

(Video) Insulated Slab Foundation
(Matt Risinger)

What is the best insulation for below grade basem*nt walls?

Often, the best insulation for basem*nt walls in terms of moisture resistance, cost, quality, and ease of installation is rigid foam board insulation. It comes in sheets that are easy to measure, cut, and install. The material is also water-resistant, so it's less likely to retain moisture.

(Video) I’m recommending we NOT INSULATE This Old House
(Matt Risinger)
What is the best insulation for below grade basem*nt?

Fiberglass insulation is coated in a vapor barrier that is ideal for locking out the moisture that is common in a basem*nt space. This material — which is known for its ability to last for years — can be easily installed with nails or an adhesive.

Do I need to insulate below grade? (2024)
How do you insulate below grade basem*nt walls?

The best way to insulate the interior side of a basem*nt wall is with foam insulation that is adhered to or sprayed directly on the concrete. Any of the following insulation materials are acceptable for this purpose: closed-cell spray polyurethane foam or either XPS, EPS, or polyisocyanurate rigid foam.

What type of insulation is needed underground?

The leading product for underground use is Armaflex Tuffcoat. This industry leading underground insulation is based on Armaflex Class O Nitrile Foam insulation which has an additional wrap-around self-seal plastic coating. This makes the product very easy to install.

Does underground pipe need to be insulated?

Underground piping systems should be protected with an insulation system that can meet the moisture and corrosion resistance requirements of direct burial to be able to provide long-term insulation efficiency.

Do you need vapor barrier in basem*nt with insulation?

After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Not every wall does. A vapor retarder is a material used to prevent water vapor from diffusing into the wall, ceiling or floor during the cold winter.

Do unfinished basem*nts get cold?

Unfinished basem*nts can often be quite cold spaces during the winter. A lack of insulation means heat escapes through the walls and floor.

Is it better to insulate basem*nt from inside or outside?

Exterior wall insulation is considered the best choice for optimum energy efficiency, too. However, interior insulation is easier and more cost-effective for many homeowners. If your basem*nt has already been constructed but is still unfinished, it's a more practical choice to insulate the interior.

Is it OK to have exposed insulation in basem*nt?

"Fiberglass insulation should never be left exposed in an occupied area, according to the American Lung Association," says ALA's Godfrey. "Exposed fiberglass insulation, once in the air, does cause respiratory reactions, such as dry, scratchy throat and coughing, as well as acting as a skin and eye irritant.

What is the best way to insulate an unfinished basem*nt?

Experts agree the best type of insulation for a basem*nt is spray foam. It provides a high degree of insulation and the closed-cell spray polyurethane foam locks out moisture. No matter what option you pick, make sure it's R-10 or higher. That will reduce heat loss by 93% or more if the R-value is higher.

What is the cheapest way to insulate basem*nt walls?

Fiberglass batt is one of the more inexpensive insulation materials available. Anyone who works with fiberglass batt will need to protect themselves with a mask and protective clothing because fiberglass is a skin and lung irritant. Fiberglass batt is more DIY-friendly than other insulation materials.

Should you insulate under basem*nt slab?

Creating an insulation layer and a vapor barrier between the concrete slab and the ground beneath it is the best practice in insulating basem*nt floors. The insulation barrier will help keep warm air in, and the vapor barrier will keep unwanted moisture out.

Is Drylok a bad idea?

DC mentioned at worse waterproofing your walls from interior with paint like drylok can cause walls at worse to rupture or collapse because water pressure has no where to go.

Is it safe to breathe in an unfinished basem*nt?

For homes with basem*nts, indoor toxins are greater than for those homes without basem*nts. Unfinished and finished basem*nts both create risks for toxic exposure throughout the whole home.

Is it unhealthy to live in a basem*nt?

Hazards commonly found in basem*nts include toxic chemicals, pests, mold, indoor air quality issues (such as dangerous gases) and fire hazards that can affect all rooms of the home. Visit the kitchen to learn more about chemicals and pests; visit the bathroom to learn more about mold.

Why don t builders insulate interior walls?

In most cases, interior walls are not insulated during construction. Unlike exterior walls, which must meet local and state codes for insulation, interior wall insulation is rarely required. This is because interior insulation has much less impact on your home's energy efficiency – but it can still play a role.

Where should you not put insulation?

Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.

How do I know if my walls need insulation?

Do the touch test. The interior ceilings, walls and floors in your home should feel warm and dry. When drywall and paneling inside a home feels damp or cold, there is not enough insulation. Alternatively, when touching an exterior wall, it should feel cold because insulation is keeping warm air inside a home.

What are 3 ways to insulate a basem*nt?

Three types of insulation are used on the exterior of basem*nt walls: rigid mineral wool boards, high-density polystyrene (Type IV) and polyurethane/polyisocyanurate boards.

Is it better to insulate basem*nt walls or ceiling?

In most cases, a basem*nt with insulation installed on its exterior walls should be considered a conditioned space. Even in a house with an unconditioned basem*nt, the basem*nt is more connected to other living spaces than to the outside, which makes basem*nt wall insulation preferable to ceiling insulation.

Do you insulate basem*nt walls before framing?

While traditional methods require building a frame before insulating a basem*nt wall, InSoFast insulation panels provide a way to accomplish both steps at once without sacrificing any insulation power.

Does basem*nt insulation need vapor barrier?

Even with proper ground water control, you will still need a vapor barrier to keep your basem*nt dry and comfortable. In addition to keeping your basem*nt more comfortable, vapor barriers and waterproofing systems can: Prevent mold and mildew growth.

What is the R-value for basem*nt walls?

The Model Energy Code recommends R-11 insulating values for basem*nt walls in most of the country and R-15 for the northernmost states.

Can you over insulate a basem*nt?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

How do you insulate bare concrete basem*nt walls?

How to Insulate Basem*nt With Foam and Stud Wall
  1. Apply Adhesive to Rigid Foam. Apply a continuous bead of foam adhesive to the back of the first insulation board.
  2. Attach Boards to the Wall. ...
  3. Frame the Wall. ...
  4. Add Fiberglass Insulation. ...
  5. Install and Finish Drywall. ...
  6. Prime and Paint the Drywall.
Jan 17, 2023

What insulation between floor and basem*nt?

Spray foam insulation can be used to insulate the floor above a crawlspace or basem*nt as well as the band joist. Spray foam provides high R-value and a continuous air barrier in one labor-saving application.

How thick of insulation do I need for basem*nt?

For basem*nts, the recommended amount is R-10 (2 inches) or better. Compared to an uninsulated concrete wall, this amount can reduce the amount of heat loss by 93%. However, more is better. Basem*nts with walls insulated to R-20 (4 inches) saw annual savings ranging from $88 to $308.

Is it OK to use fiberglass insulation in basem*nt?

Remember, fiberglass does NOT resist moisture, so it's generally a no-no when insulating basem*nts. You can reduce the risk of moisture issues if you first cover the concrete with a continuous layer of rigid foam or closed-cell spray foam.

Should you put plastic over insulation in basem*nt walls?

It is best to place vapor barriers on foundation walls in basem*nts before installing posts and doing primary insulation. Installing a moisture barrier will help keep moisture in the basem*nt and prevent it from seeping into the walls and floors, leaving no room for mold.

Is faced or unfaced insulation better for basem*nt walls?

Unfaced insulation is great for new construction, remodels, walls, floors, ceilings, basem*nts, attics and crawlspaces. It's best used for interior wall applications that do not face the outside and also in rooms that don't need moisture control, like living rooms, dining rooms and studies.

Should the ceiling of a finished basem*nt be insulated?

It is important to note that most experts agree ceiling insulation is only a consideration when a basem*nt will remain unfinished. If the basem*nt will be a finished living space, then wall insulation will provide sufficient coverage.

You might also like
Popular posts
Latest Posts
Article information

Author: Twana Towne Ret

Last Updated: 10/05/2024

Views: 6062

Rating: 4.3 / 5 (44 voted)

Reviews: 91% of readers found this page helpful

Author information

Name: Twana Towne Ret

Birthday: 1994-03-19

Address: Apt. 990 97439 Corwin Motorway, Port Eliseoburgh, NM 99144-2618

Phone: +5958753152963

Job: National Specialist

Hobby: Kayaking, Photography, Skydiving, Embroidery, Leather crafting, Orienteering, Cooking

Introduction: My name is Twana Towne Ret, I am a famous, talented, joyous, perfect, powerful, inquisitive, lovely person who loves writing and wants to share my knowledge and understanding with you.