When installing faced insulation, the facing should always point toward the interior, heated, or air-conditioned space. For example: On exterior walls, the facing should touch the drywall. In attics, the facing should point down toward the ceiling below.
If using faced insulation, keep the paper vapor retarder facing up and against the subfloor. The insulation should fit snugly against the subfloor and between the joists.
Unlike faced insulation, unfaced insulation is non-combustible since it does not contain any combustible materials such as paper or plastic. Also, as mentioned above, unfaced insulation is much cheaper than its faced counterpart. Additionally, unfaced insulation is a great way to soundproof your interior walls.
Therefore, when installing foil faced insulation always fit the foil side where the temperature difference is greatest. So, any time you use a single side foil insulation, the foil needs to be facing toward the living space.
Our view is that for mixed climates (aka heating dominated climate zones) the best place for a smart vapor barrier is inboard of the insulation because it will prevent conditioned air from entering the insulation layer and really help minimize or eliminate condensation.
Vapor Barriers
The facing of the insulation serves as a vapor barrier. Vapor barriers resist moisture penetration, keeping humid interior air from reaching cold surfaces where it could condense. In cold climates, vapor barriers go on the warm side of insulation. In hot, humid climates, they go on the exterior side.
Begin at one side of the crawl space and lay down 6-mil or thicker polyethylene plastic over the entire crawl space. Cut the sheets to size, allowing 6 inches or more along walls. Overlap the seams by no less than 12 inches and secure them together with the poly PVC tape.
To fix insulation boards to a wall using this method, start by ensuring the wall is clean and dry. Fix battens around the top and bottom of each wall. Be sure to apply a batten to each corner and around window and door frames. Then, fix the battens vertically around the room at a minimum of 600mm centres.
Which direction does the paper go? A: The paper should always be placed towards the living space according to the manufacturers we are familiar with.
It is important to leave a small air gap between boards and the mineral wool in order to stop damp forming. Remember that insulating between the joists will create a cold roof space as the heat is kept underneath the insulation like a blanket.
R13 insulation is generally more affordable, which makes it an attractive option for budget-conscious projects. However, R19 insulation offers better long-term advantages because of its higher R-value.
The most important part is determining where the dewpoint is. If the dewpoint is towards the inside, closest to the new drywall, then a plastic barrier will cause issues as it will not allow the cavity to properly dry. A permeable barrier is your safest bet, and the paper on the batts is already acting as such.
For example, if you need extra soundproofing or don't want to spend time installing a separate vapor barrier, then face may be the best option for you. However, if cost savings are more important than convenience, then unfaced may be the better choice in this case.
In finished attic rooms with or without dormers, insulate (2A) between the studs of "knee" walls, (2B) between the studs and rafters of the exterior walls and the roof, (2C) and ceilings with unconditioned spaces above. (2D) Extend insulation into joist space to reduce air flows.
If the insulation is in an unfinished basement, a crawlspace or a drive-under garage, the brown should be facing upward and not visible when you're inside and looking up. If it's in an unfinished attic, the brown should be facing down and, again, not visible if you are looking at it from within the attic.
Kraft-faced insulation includes a paper vapor retarder, which helps prevent mold and mildew. Kraft-faced insulation should be installed in exterior walls, exterior basement walls, and attic ceilings by pressing the product into the wall cavity with the paper side facing outward, towards the installer.
Faced insulation refers to batt material that has a thin outer layer of paper or plastic, known as a "face". This is used to protect the material, typically fiberglass or mineral wool batts, from humidity, bacteria, and other moisture damages.
The rule is that the insulation should always face the warm-in-winter side of the space.
Yes, House Wrap Does Come First!
Often, those installing foam insulation ask, “Do I put house wrap on first or second?” Whether you're installing James Hardie siding or not, house wrap is always applied first. The experts place the material in the proper orientation to achieve maximum insulation.
Position the start of the roll at the ridge batten with the foil facing down into the roof cavity below and roll towards the fascia/gutter. Allow the blanket to sag in between the batterns to recover to it nominal thickness. The insulation should always maintain continuous contact with the roof sheets once laid.
If the vapor barrier is facing the living space the moisture is stopped before it gets to the insulation. If the vapor barrier is installed upside down (not towards the living area) often it deteriorates the insulation and the vapor barrier and makes the insulation less efficient.
Generally, if the crawl space is going to be entered regularly for maintenance, or if items are going to be stored in the crawl space, it is a good idea to get a thicker poly starting at 12 mils. The minimum 6 mil is inadequate if the floor of the crawl space has rocks, roots or concrete chunks.