The most correct option is to provide Insulation of the roof during the construction stage. However, many homeowners, having equipped a cold attic, subsequently cover it with insulation to reduce heat loss and gain additional living space. Often, flat roofs that do not have an attic are also insulated, through which cold air enters the room.
Why do you need to insulate your roof?
Insulation of the roof is necessary since heat loss through it is almost 45%. This is explained by the laws of physics, according to which warm air always rises to the top. In the absence of adequate insulation of the roof and roof, he, not seeing any obstacles, goes outside the house.
Instead of heat, cold air descends into the building through the uninsulated surface, which always tends downward. As a result, the cold spreads throughout all rooms, pushing out heat, and almost half of the energy resources are wasted.
Numerous companies in Sydney offer insulation installation services. You can choose a professional one based on your needs and budget.
Advantages of internal insulation
In a built house, the roof is insulated only from the inside, otherwise, the entire roof will have to be removed, violating its geometry. In addition, if it rains during external insulation work, the consequences will be disastrous. Internal insulation can be carried out all year round in any weather.
As a result, additional space is formed, which can always be used. Since the insulation is covered with finishing material, only minor repairs and heating will remain in the attic. The resulting room can be used as a library, gym, etc.
Cold or warm roof – which insulation option to choose
A cold roof is a roof that is not insulated and is a building envelope. It does not protect against changes in ambient temperature. Typically, there is an attic space under the roof.
When installing a cold roof, insulation is laid or sprayed only on the attic floor adjacent to the ceiling of the rooms, and the remaining surfaces remain uninsulated. In such an attic there is no need to organize a ventilation system since the air easily exits through the roof. Therefore, cold construction reduces construction costs.
However, uninsulated space is only suitable for storing garden tools. Due to temperature changes, other things will become moldy and become unusable.
When installing a warm roof, it is covered with insulation on all sides. After this, you can store things and supplies in the attic, and after heating, you can create an additional room.
Combined insulation
In this case, two insulating materials are used, for example, mineral wool and expanded polystyrene. It is possible to use two types of insulation, for example, closed- and open-cell polyurethane foam. This allows you to combine their positive qualities. For example, polyurethane foam with open cells has high noise insulation, and with closed cells, it retains heat well. By properly combining insulation materials, you can turn your attic into a warm and quiet room.
With combined insulation, one material is placed under the rafters, and the other in the space between the rafters. Closer to the roof, dense insulation with low vapor permeability is laid, and then less dense insulation with a higher vapor penetration rate. If you do the opposite, then the air coming from the room will rest against a dense layer and will not come into contact with the soft material that retains heat. Therefore, in construction there is a rule – when designing walls, insulating layers are placed with a decrease in vapor barrier ability from the inside to the outside.
When using polyurethane foam, insulation is applied in two layers – first closed-cell with a low vapor barrier, and then open-cell with a higher rating.
Hydro- and vapor barrier when insulating the roof from the inside
Improper installation of hydro- and vapor barriers leads to wet insulation and destruction of the rafter system. In such a house, mold stains appear on the ceiling and walls, and there is an unpleasant damp smell in the rooms. Sometimes wallpaper peels off due to high humidity.
Most often this happens when during installation the hydro- and vapor barrier film is confused or low-quality material is purchased.
The fact is that the materials for vapor and waterproofing are different. The purpose of a vapor barrier is to prevent water vapor generated in the house due to breathing, cooking, and ironing from being absorbed into the insulation. The same material will not allow moisture that gets inside the insulating material through the external waterproofing to penetrate the rooms. Therefore, the vapor barrier film is moisture-proof on both sides.
Waterproofing only keeps moisture out from the outside, preventing it from wetting the insulation. In the opposite direction, i.e. from the side of the room, there are no obstacles to the evaporation of water. This is necessary so that the insulating material can dry out when exposed to water. Therefore, both types of film are marked.
Vapor barrier
How to distinguish vapor barrier from waterproofing:
- The waterproofing film acts as a membrane, therefore it has minute perforations and is not transparent. There are two-layer models with a fleecy bottom layer. The material is laid directly under the roof with an overlap so that water does not flow into the resulting joints. When insulating the roof from the inside, the waterproofing layer plays the role of a windproofing layer.
- The vapor barrier is impenetrable to air in both directions. Outwardly, it looks like dense polyethylene. Films are available with a foil coating to protect against sunlight. This material is laid with a shiny layer in the direction away from the room.
- When insulating the roof from the inside, you need to remember that the waterproofing is placed between the insulation and the roof, and the vapor barrier covers the insulating material from the side of the house.
In order not to suffer with films and not take risks, it is better to choose insulation that does not absorb moisture and does not require insulation from moisture. One such material is sprayed polyurethane foam, which is applied directly to the roof between the rafters and does not allow moisture to pass in any direction.
Features of insulation of a pitched roof
A pitched roof is characterized by the presence of two or more planes located at an angle. Therefore, two-, four-three-slope and multi-gable roofs are distinguished, having several pitched surfaces. All of them are united by the possibility of arranging a residential or warm utility room in the attic. The main thing is to properly insulate the roof.
Materials used to insulate a pitched roof must have the following properties:
- low thermal conductivity, otherwise cold will spread from the roof, especially if it is covered with metal material;
- durability, since opening the insulating “pie” of a pitched roof is quite difficult. Ideally, the insulation should last 50 years;
- high noise absorption, especially if the attic space is planned to be residential. Otherwise, the owners will constantly hear the sound of drops on the roof.
- The classic option for insulating such a roof is a “pie” made of insulation, hydro- and vapor barriers. A simpler and more win-win option is spraying polyurethane foam. Both methods make it possible to completely transform the attic into a warm room.
Recently, management companies have begun to insulate the pitched roofs of multi-story buildings from the inside. This helped to significantly reduce heating costs and prevent cold air from entering the upper floors. In such buildings, polyurethane foam spraying is used, because… This method allows you to quickly insulate a large attic or technical floor.
Also Read: Best Waterproofing Services In Lahore
Insulating a flat roof from the inside
In constructed houses, the flat roof is insulated from the inside – from the side of the rooms, so as not to remove the existing roofing material.
Since such buildings do not have an attic, when insulating the roof from the inside, you have to sacrifice some of the height of the rooms. Another disadvantage is the need to dismantle wiring and lamps.
First, wooden guides are nailed to the ceiling, between which the insulation will be laid. The first bars are nailed along the perimeter of the room, and then gradually cover the remaining space. The height of the sheathing is selected according to the thickness of the insulating material.
If the insulation is soft enough, for example, basalt wool or mineral wool, the cells are made slightly narrower than the rolls. Then the material will be fixed and will not fall out.
After installing the sheathing, the insulation is placed between the guides, and attached with special adhesives or mastics. A vapor barrier film is placed on top to prevent water vapor from entering residential premises.
As a vapor barrier, thin wooden beams are attached crosswise to the sheathing, and plasterboard or other finishing material is placed on them. Air can circulate in the resulting space. Wires for connecting electrical appliances are also laid here.
