Building Science Attic Access

Otherwise the insu lation gets compressed or kicked around which diminishes its r value.

Building science attic access.

Attics should be air sealed prior to adding insulation. These are significant challenges. A well ventilated attic has almost no impact on radiant transfer of heat between the underside of the roof deck and the top of the insulation. In the world of building science we call them attic kneewalls walls that separate conditioned space from an unconditioned attic.

A 10 square foot hatch in a 100sf attic can halve the effective value of the attic insulation. Attic space can be used for storage but only if you build an elevated platform above the insulation. The intent of this guide is to provide information for the preparation work necessary prior to adding attic insulation. Specific topics covered include the three types of heat transfer.

Traditionally building codes have required attic ventilation. The intended purpose was to allow warm air and moisture to escape. People who have a bonus room find that it s often the least comfortable room in the house. They re also the cause of many comfort problems especially in bonus rooms.

Adding insulation alone does not save much energy and can lead to health and durability problems. An understanding of heat transfer can guide informed investments and best practices for improving home energy efficiency. You can build an airtight entry to the. Attics or roofs can be designed and constructed to be either vented or unvented in any hygro thermal zone map 1.

As such there is no energy benefit to vent an attic in a hot humid climate but there is alarge moisture penalty due to the moisture being brought into the attic by venting the attic. What s wrong with attic kneewalls. Vented attics can be effective as long as hvac ducts are not located in them and the ceiling deck is well air sealed and insulated. This means if you ve installed r 38 insulation in your entire attic and forgot the hatch the result is the same as if you insulated the attic and the hatch with just r 17.

The choice of venting or not venting is a design and construction choice not a requirement determined by the physics or by the building code. Upcoming events renovation and rehabilitation. The model building codes allow both vented and unvented roof assemblies. A building science consulting and full service architecture firm specializing in building technology for all types of buildings including commercial institutional and residential.