if it is hot outside, the reflective part of your foil insulation must face outside. if it is freezing outside, the best orientation of the reflective part is inside. if you press the foil side of the insulation tight up against the wall (foil facing outward), the radiant barrier will not work.
The fibre side is laid in contact with the ceiling. If you were creating a warm attic by insulating between rafters, then you would want little temperature difference between the inside insulation surface and the room. So the foil side should face the slates and the fibre side the attic space.
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.
(The general rule for insulation is that the facing always goes toward the conditioned space.) The second layer of insulation should be unfaced so that moisture doesn't collect between the layers.
Start laying the insulation furthest away from the access hole then work your way back from the outside edges in. Install the insulation between the ceiling joists and butt pieces together at all joins.
if it is hot outside, the reflective part of your foil insulation must face outside. if it is freezing outside, the best orientation of the reflective part is inside. if you press the foil side of the insulation tight up against the wall (foil facing outward), the radiant barrier will not work.
Installing it
The reflective side must be facing downwards when in roofs, upwards when installed underneath a floor and inwards when installed in walls.
Faced insulation is better at preventing moisture damage; however, it can't be layered like unfaced insulation. For this reason, unfaced insulation is better for keeping your house warm in the winter.
When installing fiberglass insulation in your home, be sure to put the paper or foil vapor barrier facing toward the heated and cooled living area of the home (down in attics, up under floors, in on walls) to prevent condensation from occurring.
It has to go rougher side up, but there is no specific top or bottom. Make sure the felt placed higher up overlaps the lower piece. Do I need to spread a layer of tar on the roof before laying the felt? You don't need to apply any tar before laying the felt, however it depends on your needs.
Remember: When installing during cold climates, the vapor barrier should face the home's interior. Conversely, the vapor barrier should face the house's exterior during hot weather climates.
(Source: NRCA.) In the event you are erecting a “cold building” (such as a refrigeration building) that stays at 32 F (0 C) degrees or less inside, you will need a vapour barrier on the outside of the insultation to prevent warm exterior air from entering and potentially damaging the roof's insulation. (Source: NRCA.)
With most brands of membrane, the printed side will be facing outwards. However, always ensure to double-check any installation instructions provided by the manufacturer. Draping the breathable roof membrane instead of laying it taught ensures that the moisture does not run off quickly.
It's important to leave a ventilated air gap between the insulation and the boards to prevent condensation on the underside of the boards.
Do you have any plans for furnishing/fitting out your attic in the future? Then you could simply insulate the pitched roof. But the best solution is actually to insulate both the attic floor and the underside of the roof.
Pink towards the heat! For most insulation, the paper acts like a vapor barrier. Inside your house, that goes towards the warm side (usually the walls). Think of it like a cozy sweater facing inwards.
Yes, too much loft insulation can cause dampness in some situations. Loft insulation works by trapping warm air inside a building, preventing it from escaping through the roof. This helps to keep the interior of the building warmer in cold weather, reducing the need for heating and saving energy.
You can put all the insulation on top of the roof deck, all the insulation on the underside of the roof deck, or some on top and some below. You can put it all below the roof deck but use two different kinds. Your insulated roof can be a cathedral ceiling or it can be above a conditioned attic.
You can use faced or unfaced batting when installing between the roof rafters of finished attic spaces. When using paper or plastic batting insulation, that moisture barrier should face outward toward the attic space. Even if the attic space is unheated, it's typically warmer than the outside air in winter.
Leaving Too Many Gaps
One of the biggest problems DIY homeowners face is leaving too many gaps in their insulation. Gaps or insulation that isn't secured correctly can leave the building structure open to air and moisture leaks. Spray foam insulation is best for reaching into small cracks and any areas left open.
Still, certified attic specialists may also use them during a major remodeling project. In open-cell spray foam installations, the typical R-value ranges from 3.5 to 3.6; in closed-cell spray foam installations, the average ranges from 6.0 to 6.5.
If you have an even, full coating of snow: congrats, you, and your attic are well insulated. If there are melted patches or the entire upper half of the roof is clear of snow: you want to address the lack of insulation either in your attic or between your heated living spaces and the attic above.
Foil has a shiny side and a dull side because of how it is manufactured. Unless you are using foil that's labeled non-stick, which does have a non-stick side, it does not matter what side you use. Both the shiny and dull sides can be used the same way to cook, freeze, and store food.