Building Science Attic Access

A vented attic where insulation is placed on an air sealed attic floor is one of the most underappreciated building assemblies that we have in the history of building science.

Building science attic access.

So much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus. These openings not only allow mechanical and electrical contractors to. The general rule of thumb suggests installing at least 1 sq. 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.

A vented attic works in hot cli mates mixed climates and cold climates. The intent of this guide is to provide information for the preparation work necessary prior to adding attic insulation. Attics should be air sealed prior to adding insulation. Building science fundamentals see all events a building science consulting and full service architecture firm specializing in building technology for all types of buildings including commercial institutional and residential.

It works in the arctic and in the. A 10 square foot hatch in a 100sf attic can halve the effective value of the attic insulation. Adding insulation alone does not save much energy and can lead to health and durability problems. A vented attic where insulation is placed on an air sealed attic floor is one of the most underappreciated building assemblies that we have in the history of building science.

In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof. Attic access panels serve as an important safety and convenience feature in the home. The minimum size for an attic s access. For over 20 years rdh has continued to lead change in making buildings better through the integration of science design and construction expertise.

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. So i ll start by saying something that might sound controversial but really isn t. Of vent for every 300 sq. The rdh difference for us building science underpins everything that we do.

Throughout the balance of this digest the terms attic and roof will and can be used interchangeably. Even attic hatches that are insulated can still be problem areas in the attic. It s hard to screw up this approach. The science behind attic ventilation however is sound.