While ceiling insulation is a simple job for a diy er s new or existing build roof insulation can only be installed during the construction of a new roof.
Roof vs ceiling insulation.
It s more effective and easier to install insulation on the attic floor than in the roof assembly.
Roof is the top most part of the structure of a part while ceiling is what you look at when inside a room roof protects the inside of the building from heat cold and rains while a ceiling is mostly for aesthetic purposes.
Looking upward through the open ceiling if the exterior wall and roof deck assemblies both contain spray foam then a continuous insulation and airtight layer is established from the base of the walls to the peak of the roof.
Box out light fixtures.
Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be.
Wall insulation is not suited for use in a ceiling cavity space and wall insulation r values would not be adequate for your ceiling area.
If you do need to install insulation in the roof assembly take into account some rules.
Check garage walls and ceilings that are adjacent to conditioned spaces.
Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces.
Insulating in and around your roof attic space also prevents long term damage from moisture build up or ice damming which results from the warm air trying to escape through the apex of the roof but instead heating up the snow.
Turn off the electricity then remove an electrical outlet cover for a view of exterior insulation.
Unless in air conditioned attics insulation is typically installed on the ceiling plane not on the sloped roof assembly.
Exterior walls and floors.
See the department of energy s doe ranges for recommended levels of insulation below.
Ceiling insulation sits on top of your ceiling plasterboard whereas roof insulation also known as roofing blanket sits directly against the underside of your metal roof.
For example cathedral ceilings built with 2x12 rafters have space for standard 10 inch batts r 30 and ventilation.
The highest r value that wall insulation reaches is an r2 7hd however we recommend a minimum of r4 0 for ceiling insulation.
A very energy efficient enclosure results.
It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.
Check behind knee walls which are walls between living spaces and the garage or attic.
Additionally insulation serves as a way to enhance sound proofing on the uppermost envelop of your house.
Image courtesy of d7 spray foam insulation houston tx.