Attic Insulation Rafters Or Joists

Insulation between the joists will make your attic much colder so this could worsen your damp problem.

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. If you want to install standard r 38 insulation. 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. The ceiling load may include items like drywall ducts recessed lights bathroom fans and attic insulation.

You can use rigid foam panels or do as tom silva does with nearly all houses these days. 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 batting material must be faced and. 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.

Install batting between the attic s floor joists. Even rafter insulation can encourage damp as it stops draughts and reduces natural ventilation. 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. If you decide on mineral wool such as glass wool or rock wool you will need to put down a damp proof membrane.

In practical terms you can choose between mineral wool or insulation boards. Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly. 2d extend insulation into joist space to reduce air flows. 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.

So insulating the floor of the attic is not only the best solution but it is also the simplest and cheapest. Hire a pro to install spray foam insulation. 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.