Insulating Exposed Enclosed Porch Roof Rafters

You can prevent this by installing foam insulation board against the underside of the roof between the rafters.

Insulating exposed enclosed porch roof rafters.

The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow. Large foam insulation sheets can be nailed directly against the floor above or held in place by chicken wire or other metal elements with the facing against the underfloor. Use a vapor barrier to keep your floor above free from condensation caused by the new insulated area. Make sure that you wear gloves and a mask for protection.

In essence the boards are laid horizontally over the timber across the roof area beginning and ending on a rafter or top chord. The boards are secured by a screw fixed counter purlin running from eave to roof ridge above each rafter or top chord. You can install a combination of r 20 rigid foam above the roof sheathing and r 29 or more of air permeable insulation fiberglass batts or cellulose for example between the rafters and in direct contact with the roof sheathing above. This is often a layer of tongue and groove boards nailed to the exterior side of the exposed rafters.

The insulation should fit snugly to prevent air from getting through. One drawback to this is that the layer of insulation placed above the ceiling is missing which can subject the area of the house with the exposed rafters to extreme temperature changes. This can be stapled up between the floor joists. An open ceiling is another option where the rafters that support the roof are left exposed.

Covering up the soffit vents with loose fill or batts which can happen if you stuff insulation along the eaves is a huge no no. For the same reason insulation shouldn t touch the roof s underside. This is a more rustic choice and you can use contrasting planks with the exposed rafters to add dimension and visual interest to your porch. The screws secure the counter purlin to each rafter or top chord.

Many homeowners like a classic drop ceiling with painted or stained beadboard for a traditional look. To create a warm pitched roof insulation such as kingspan kooltherm k7 pitched roof board should be fitted between and over the rafters. The insulation for exposed rafters is installed on the exterior side of the finish ceiling. If you can crawl under your porch insulate from below by nailing plywood boards to cover any openings.