Attic Insulation Rafters Or Joists

The batting material must be faced and.

Attic insulation rafters or joists. Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly. Joists are traditionally made from timber. Install batting between the attic s floor joists. If you want to install standard r 38 insulation.

The ceiling joist system is typically constructed from substantial two by tens or larger dimension boards but some older homes have smaller joists. Even rafter insulation can encourage damp as it stops draughts and reduces natural ventilation. 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. 2d extend insulation into joist space to reduce air flows.

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. 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. 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. 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.

So insulating the floor of the attic is not only the best solution but it is also the simplest and cheapest. If you decide on mineral wool such as glass wool or rock wool you will need to put down a damp proof membrane. Insulation between the joists will make your attic much colder so this could worsen your damp problem. The ceiling load may include items like drywall ducts recessed lights bathroom fans and attic insulation.

Insulating attic floors unfinished or uninsulated attics need a layer of protection against air migration. In finished attic rooms with or without dormer insulate 2a between the studs of knee walls 2b between the studs and rafters of exterior walls and roof 2c and ceilings with cold spaces above. Hire a pro to install spray foam insulation.