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.

Attic insulation rafters or joists.

If you want to install standard r 38 insulation. Even rafter insulation can encourage damp as it stops draughts and reduces natural ventilation. 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. 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.

If you decide on mineral wool such as glass wool or rock wool you will need to put down a damp proof membrane. 2d extend insulation into joist space to reduce air flows. The ceiling joist system is typically constructed from substantial two by tens or larger dimension boards but some older homes have smaller joists. Insulation between the joists will make your attic much colder so this could worsen your damp problem.

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. 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. 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.

The batting material must be faced and. You can use rigid foam panels or do as tom silva does with nearly all houses these days. 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. So insulating the floor of the attic is not only the best solution but it is also the simplest and cheapest.

Install batting between the attic s floor joists. 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.