Warm Roof Venting And Insulation

Our original design actually called for a hybrid with a vapor membrane beneath the rafters then 5 5 of roxul batts in the rafters below the sheathing and then roxul insulation boards atop.

Warm roof venting and insulation.

To provide adequate ventilation and to avoid condensation in roof voids pitched roofs that have insulation at ceiling level should be ventilated to the outside air. Beyond the decreased capacity for insulation when venting the roof deck venting the roof deck or the attic has some other drawbacks worth considering. Ventilation openings should prevent the entry of birds etc. In pitched roof construction thermal insulation can be placed horizontally at ceiling level cold roof.

Ventilated cold roof or warm roof with insulation boards atop sheathing which serves to raise the dew point above the structural members of the roof. Inclined along the line of rafters warm roof or positioned within the roof. The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow. A warm deck roof is where the insulation is placed on top of the rafters joists and the roof covering is then placed over the insulation.

And current best practice. Where the insulation is placed above the structural deck warm deck and either above or below the waterproofing. 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.

You only need ventilation in a cold roof. No ventilation is required for these types of roofs. Jonathan taylor s article unpacks the key issues including the role of moisture ventilation and buffering. A cold roof is where all of the insulation is placed either between and under or completely under the joists or deck.

No insulation is on top. Ventilated roofs remove moisture from roof cavities structural members sheathing and insulation. The term cold roof refers to traditional roofs in which insulation is placed in the ceiling of the home so it is underneath the attic space which is not conditioned. These roofs include a.

There is no need for additional ventilation. In cold climates snow can enter the soffit and ridge vents melt and potentially cause rot. Fabrications with 3mm 10mm openings are acceptable. Cold roofs versus warm roofs.

To be sure your roof is getting enough ventilation there are simple calculations that you can follow. The roof will need to be checked to see if there is any insulation either within the joists or on top of the joists as a warm roof construction. In this way the roof itself is kept cold.