How To Insulate External Walls Above Ground With Styrofoam?

To install foam board insulation on exterior walls, follow these steps: 1) Prepare the walls, 2) Measure and cut the foam board insulation, 3) Apply adhesive to the foam board insulation, 4) Attach the insulation to the exterior walls, 5) Secure the insulation in place, 6) Seal the gaps and edges, and 7) Finish the wall surface.

The best time to insulate on the exterior of basement walls is before backfilling around the basement. Exterior foam insulation reduces thermal bridging across the wall through framing members and keeps the sheathing warmer, reducing the risk of condensation and mold growth. Polyisocyanurate (polyiso) foam board has R-values ranging from R-6.5 if 1-inch thick. Kraft-faced fiberglass insulation helps control temperature and humidity inside the structure.

To increase insulation level in existing homes, remove the exterior cladding and install rigid foam insulation, possibly new. Use construction adhesive or silicone sealant where the foam laps wall plates and outside corners, and housewrap tape over all seams. Fill stud cavities with a minimum of 100mm rigid foam insulation and cover the entire face of the wall with 25mm rigid foil-faced insulation.

Epoxy-coated steel screws up to 30cm can be used to attach the foam to the sheathing, then use longer screws to fix furring. The foam can be attached to the foundation wall with tap-cons and caps, foam glue, or mechanical attachment with screws or nails.

Do I need a vapor barrier on exterior wall insulation?

Building codes mandate the use of vapor barriers with insulation to improve indoor environmental quality and energy efficiency. Building scientists recommend this method, as it protects against diffusion. Polyguard recommends a quality air barrier system to limit infiltration, exfiltration, and moisture accumulation in the building envelope. Contact Polyguard professionals for more information on when to use a vapor barrier with insulation.

How do you insulate exterior walls from the outside?

To insulate old houses, focus on the exterior walls by applying a house wrap/vapor barrier, attaching foam board insulation, installing siding, replacing old windows with energy-efficient units, caulking window trim, and using weatherstripping to reduce air leaks. Before insulating, learn how to safely insulate different parts of an old home, such as the attic and roof. The average home loses about a quarter of its heat through the roof, so sealing the attic is a safe first step to retaining heat and saving energy. This will help keep old houses warm and toasty.

Can I put foam insulation on exterior walls?

Extruded polystyrene (XPS) and foil-faced polyisocyanurate (polyiso) are high-density rigid-foam insulations approved for exterior use as drainage planes by Building America. They require sealed joints for effective water-resistivity. Insulation sheathing membranes use tape to complete the air barrier, which should be applied on a clean, dry, warm surface. The vertical plane of the exterior face must be smooth and continuous for water-resistance.

Rigid polymeric foam sheathing with sealed joints is the lowest cost and highest performing rainwater management strategy. However, sealing joints in this method is a challenge. Building America Solution Center provides best practices for taping rigid foam.

Which side of styrofoam insulation faces out?

It is recommended that the reflective side of a board be oriented towards the exterior, while the non-reflective white side should be oriented towards the interior. Nevertheless, in the event that vinyl siding is installed over AP™ Foil-Faced sheathing, foam boards must be installed with the white non-reflective side facing the vinyl siding.

What is the disadvantage to using rigid foam sheathing on exterior walls?

Rigid foam insulation, also known as foam board or board-stock, is a popular choice for insulating foundations and building exteriors in residential and commercial buildings. It is made from foam plastics and can be used inside wall cavities. Rigid foam offers high R-values compared to loose-fill insulation, with ratings ranging from R-4 to R-6. 5 per inch. Some rigid foam products are water resistant and can be buried to insulate foundation exteriors.

Expanded polystyrene board (EPS) is the greenest choice, as it does not use HCFCs in its production. It can be water-resistant and used underground. Extruded polystyrene board (XPS) has a slightly higher R-value than EPS and is more resistant to moisture. Polyisocyanurate board (polyiso) offers even better insulating value, reaching from R-6. 5 to R-8 per inch, but is the least ecological option. Polyiso board is manufactured with various facings to further improve its R-value.

How do you attach Styrofoam to an exterior concrete wall?

In order to install wall finishing, it is necessary to use masonry nails or screws to secure “furring strips” on block walls. This is followed by the application of a tightly fitting Styrofoam or “ISO” board with a foil or plastic backer for a moisture barrier, and then the wall finish is fastened.

What happens if insulation is installed backwards?

Incorrect insulation installation can lead to condensation buildup, musty smells, wood rot, and mold issues, negatively impacting indoor air quality. The vapor barrier on the wrong side prevents moisture from escaping, causing constant dampness that rots structural materials like wood and drywall. Mold spores thrive in moist environments and can trigger allergic reactions or respiratory problems when inhaled.

To fix this issue, remove insulation and inspect for moisture or mold before reinstalling or replacing it. Look for dark or discolored areas and musty odors, and use a moisture meter to check moisture content. If mold exists, have a professional perform mold remediation before adding new insulation.

Does foam board insulation need a vapor barrier?

The necessity of a vapor barrier in foam rigid insulation depends on the specific situation. In colder climates, an extra vapour barrier is often recommended to prevent moisture from penetrating the insulation layer, which can lead to condensation and damage. In high humidity areas like bathrooms, laundry rooms, or kitchens, a vapour barrier is typically recommended to prevent moisture buildup and damage.

This is especially important for PIR foam insulation, as the foam material can absorb moisture and potentially degrade over time, especially at joints or gaps where moisture can infiltrate. In summary, the necessity of a vapor barrier depends on the specific situation and the specific needs of the insulation.

What is the best foam insulation for exterior walls?

In cold climates, closed-cell spray foam is the best insulation for exterior walls due to its high R-value per inch, which effectively resists heat flow and serves as an air and moisture barrier. Insulating exterior walls from the inside is possible, often done in existing homes where exterior modifications are impractical. Options include blown-in cellulose for filling existing wall cavities and spray foam insulation for excellent air sealing. The R-value of the best insulation for exterior walls varies by insulation type and wall structure, and it’s beneficial to choose an R-value that meets or exceeds local building codes.

Typical R-values include fiberglass insulation (R-13 to R-15 for 2×4 walls, R-19 to R-21 for 2×6 walls), foam board insulation (R-4 to R-6 per inch), spray foam insulation (R-6. 5 to R-7 per inch), andcellulose insulation (R-3. 5 to R-4 per inch).

How thick should exterior foam insulation be?

The Energy STAR Single-Family New Homes program requires that ceiling, wall, floor, and slab insulation levels meet or exceed those specified in the 2009 International Energy Conservation Code (IECC) with some alternatives and exceptions. The exterior foam layer should be foil-faced polyisocyanurate or XPS, and the layer should be at least 1 inch thick. The compliance tab contains program and code information, with code language excerpted and summarized below.

If the state or local residential building energy code requires higher insulation levels than those specified in the 2009 IECC, the building must meet or exceed the locally mandated requirements. Some states have adopted the 2012 or 2015 IECC, and the U. S. DOE Building Energy Codes Program can be used to see which code has been adopted in each state.

Which way should insulation face on exterior wall?

When faced insulation is installed correctly, it prevents condensation by pointing towards the interior. However, a facing that traps moisture inside the insulation can cause issues. Both vapor barrier and faced insulation should be used together for optimal protection. Adding a dedicated vapor barrier on the interior can provide additional moisture protection. If the facing is installed backward, it is crucial to reinstall the insulation properly to avoid mold, rotting, and reduced performance.