Attic Insulation Rafters Or Joists

If you decide on mineral wool such as glass wool or rock wool you will need to put down a damp proof membrane.

Attic insulation rafters or joists.

Unless expressly built so an attic s joists are meant for carrying the load of the ceiling below and related elements collectively known as the dead load. Joists are traditionally made from timber. The batting material must be faced and. Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly.

If you re considering turning your attic into conditioned storage or living space it s worth changing tactics to insulate between the rafters and wall joists instead of the floor. Hire a pro to install spray foam insulation. You can use rigid foam panels or do as tom silva does with nearly all houses these days. In practical terms you can choose between mineral wool or insulation boards.

They are nominally 2 inches thick actual width usually 1 1 2 inches and come in a variety of widths from 8 to 12 inches. The ceiling joist system is typically constructed from substantial two by tens or larger dimension boards but some older homes have smaller joists. 2d extend insulation into joist space to reduce air flows. Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches.

Insulating attic floors unfinished or uninsulated attics need a layer of protection against air migration. If you want to install standard r 38 insulation. Even rafter insulation can encourage damp as it stops draughts and reduces natural ventilation. The ceiling load may include items like drywall ducts recessed lights bathroom fans and attic insulation.

Polyurethane or polystyrene spray foams can provide thorough coverage to roof rafters and attic walls in much less time than is needed for other materials. Install batting between the attic s floor joists. Joists are the parallel horizontal beams that run across an open space joining opposite walls in a building to support both the ceiling below and the floor above.