Build Daily

Winterizing Your Home

August 12, 2017 18:06

How to properly insulate the ceiling under the cold roof

According to the laws of physics, heated indoor air rises to the ceiling and the floor if the attic has insufficient insulation, the heat goes out - this process is called the heat loss.In order not to "heat" out and save as much of the heat in the house, it is necessary to carry out the thermal insulation of the ceiling.You should know that through the ceiling and the roof can go from 25 to 40% of the heat.It is especially important to take into account that if the house is "cool" roof.

How to properly insulate the ceiling under the cold roof

How to properly insulate the ceiling under the cold roof

How to properly insulate the ceiling under the cold roof - it is best to think through in advance, in the process of building a house, but sometimes we have to do and already constructed buildings.

Warming overlap carries not one, but three features required for a comfortable microclimate in the house:

  • Insulating material is an excellent sound insulator at the same time, so it will keep silence in the house during a heavy rain and wind.
  • In winter, the material retains heat in the rooms, as rising to the ceiling and finding no "bridges" for free release, it drops down again, remaining in the room.
  • In the summer heat insulation creates an obstacle hit the heated air into the room from the outside, so they will remain cool.

There are a lot of materials and methods of using them to make a ceiling thermally insulated home.To select the appropriate installation complexity and cost, you need to consider a few of them.

Types of thermal insulation materials for the ceiling of the house

Article Contents

  • 1 Types of thermal insulation materials for the ceiling of the house
    • 1.1 Mineral wool
    • 1.2 Keramzit
    • 1.3 Ecowool
    • 1.4 Styrofoam
    • 1.5 Polyurethane
    • 1.6 Video: review of modern insulating materials
    • 1.7 Sawdust
  • 2 How do I find the required thickness of the insulation ceiling - Calculator
  • 3 warming ceilingfrom the premises
    • 3.1 Preparation ceiling
    • 3.2 Installing insulation with glue
    • 3.3 installation of insulation between the guide battens
  • 4 ceiling Thermal insulation from the attic
    • 4.1 mounting plates orinsulation mats
    • 4.2 Spray insulation material
    • 4.3 warming of bulk materials
      • 4.3.1 Video: example of attic floor insulation sawdust

When selecting a heater you need to pay special attention to the following criteria:

  • thermal conductivity.The lower is the value, the better.
  • Moisture is particularly important for the heater to be mounted on the part of the attic.
  • Flammability material must be low, or the material must be completely noncombustible.
  • long-term operation of a heater.
  • ecological purity of raw materials and binders, which make up a thermal insulator.

There are individual parameters for each of the materials, which will be considered when considering the heaters in the future.

for insulation of the ceiling and the whole attic floor is usually used:

  • mineral wool (basalt and glass), are produced in rolls and mats.
  • Keramzit various factions.
  • sawdust and small chips.
  • Ecowool, which is produced from cellulose.
  • extruded polystyrene or foam.
  • Polyurethane or Penoizol.

addition to these heaters, ceiling insulation traditionally always used dry leaves and straw.I must say that even today some masters are in no hurry to give them up, but their installation requires knowledge of the technology, because in itself this is not a natural material and water resistance is not durable.

All heaters used for thermal insulation of the ceiling, are lightweight, so they should not burden the floor structure.

The following table shows some of the characteristics of popular heaters:

material parameters Materials Thickness
50 60 80 100 120 150 200 250
density kg / m³ Mineral wool 100-120
Styrofoam 25-35
Polyurethane 54-55
Thermal resistance, W / (m² × ° K) Mineral wool 1.19 1.43 1.9 2.38 2.86 3.57 4.76 5.95
Styrofoam 1.35 1.62 2.16 2.7 3.24 4.05 5.41 6.76
Polyurethane 1.85 2.22 2.96 3.7 4.44 5.56 7.41 9.26
Thermal conductivity, W / (m × ° K) Mineral wool 0,038-0,052
Styrofoam 0,036
Polyurethane 0,027

Mineral wool

mineral wool can be called the most popular material forceiling insulation.It is used for packing and by the attic rooms, as it is by its characteristics are well suited to these operations.

mineral wool made from different materials - a blast furnace slag, cullet and sand, as well as the basaltic rock.

  • Slag

Immediately it should be noted that a material made from blast furnace slag (slag) is ill-suited for thermal insulation of a house.In the attic can be increased humidity, especially in spring and autumn, and it is very hygroscopic, which significantly reduces its insulating qualities.Residual acidity of the material is very negative effect on other building materials, particularly ferrous metals.

Slag - in a residential building of little use

Slag - in a residential building of little

Slag has a caustic and brittle fibers, so it is not recommended to be used in residential areas, because of their smaller particles can get to be suspended in the air.

its only advantage - low price compared with other types.

  • Glass wool.

This insulation is made from molten glass mass from which fibers are stretched thin.Further, they are formed from webs, rolled into rolls or cut into individual mats.Glass wool has a lower thermal conductivity than the slag and basalt insulation and moisture absorption of the material is 0,55 ÷ 0,8 kg / m².

Glass wool for insulation is not desirable to use the inside of the ceiling

glass wool is undesirable to use for insulation of the ceiling inside

glass wool is used for thermal insulation of attic floors in buildings constructed of different materials, often - in combination with other heat insulators.However, it should only be used for laying from the attic, as its fiber as well as that of the slag wool, fragile and brittle, can cause irritation of the skin and mucous membranes, so desirable of their getting into the premises.

  • Basalt wool.

Basalt heat insulation material is made of gabbro, basalt and is the best option for ceiling insulation from the premises of all the "brothers".Fibers - more plastic, so less brittle.They are tightly pressed into mats, which have sufficiently good strength.The material is resistant to external factors, so is suitable for mounting on the part of the attic.Insulation can be sold in rolls or plates, having a different density.

The optimal choice among all mineral wools - Basalt

optimal choice among all mineral wools - Basalt

Basalt wool can have a foil layer, which, when properly installed will increase the Insulating effect by reflecting heat into space.

A common drawback for all types of mineral wools are of a binder consisting of phenol-formaldehyde resins, which are constantly released into the air, which is dangerous for the health of residents of the building.So consider this insulation is fully environmentally friendly can not.


Expanded clay - an environmentally friendly material because it is made from natural clay, so is perfect for insulation attic floor.It is non-flammable and does not emit harmful substances when heated.The mound of it may have a different density, as expanded clay made in various fractions, and the smaller size of the grains or granules, the greater insulation density lower quality.

Claydite various factions

Keramzit various factions

fraction mm Bulk density kg / m³ Bulk density kg / m³ Compressive strength, MPa
1-4 400 800-1200 2,0-3,0
4-10 335-350 550-800 1,2-1,4
10-30 200-250 450-650 0,9-1,1

to insulate the ceiling, the best choice would be a concrete block having a grain size of 4-10 mm.

Keramzit does not dust and do not cause allergic reactions.The heater has a long life and does not lose its original quality throughout the entire application period.

material has high heat resistance, so they are often separated from the chimney hardwood floor by filling it in a metal tube arranged around the entrance box.

The table below shows the comparative characteristics of two eco-friendly materials - expanded clay and ecowool, which now will be discussed.

material parameters clay gravel Ecowool (cellulose)
Thermal conductivity, W / (m × ° K) 0,11-0,16 0,038-0,041
density kg / m³ 200-400 42-75
density junction to design depending on the faction:
- 15-20 mm - the presence of voids;
- 5-10 mm - a snug fit.
close fit, good scores all the cracks and crevices
Water vapor permeability mg / Pa × m × h 0,30 0,67
chemical inertness neutral
Flammability nonflammable G1-G2 (weakly combustible material processed as flame retardants
Moisture absorption,% by weight 10-25 14-16


Thisinsulation is not as popular as rock wool or foam, but it is increasingly used for insulation of floors and walls of private homes. Ecowool consists of small cellulose fibers and laying it made a "wet" or "dry" method.

One of the most promising heaters - ecowool

One of the most promising heaters - ecowool

  • «dry» method involves spillage, distribution and compacting the insulation between the joists, or mounted on a lag them.
  • for mounting "wet" method require special equipment, where the fibers are mixed with an adhesive composition, and wet ecowool under pressure through a special tube is supplied and distributed over the surface.
Spray Cellulose Fibre with a special compressor equipment

ecowool Spray with a special compressor equipment

material Advantages:

  • Ecowool can be laid a layer of any thickness, as it has a very low weight, even in compacted form, and without weighing the attic floor.Thanks to the "lightness", it perfectly insulate the ceiling.
  • This insulation consists of environmentally friendly materials and does not emit toxic substances into the premises.
  • Ecowool has quality "preserve" of the surface, preventing mold or form other types of microorganisms.
  • heat insulator has a long life and does not lose throughout their quality time.
  • layer may be added and densified if necessary.Placement of the material is carried out quickly enough, especially if the special equipment used for it.
  • Ecowool is poorly flammable and self-extinguishing insulation, as in the production of fire-retardant treated.It is not much smoke and does not emit hazardous combustion products.
  • forming a seamless and airtight coating, insulation and protects against the cold and the heat.
  • Importantly, cellulose wadding - a "breathable" material, so it will not trap moisture.

payback period of such warming will be two - three years, depending on the method of installation and the thickness of the applied layer.


foam for thermal insulation work has been used for over half a century, and during that time showed how their positive qualities, as well as numerous shortcomings.But, despite the recent, it continues to be used because it is simple to install and has an affordable price.

foam is most often used in conjunction with the mounting foam that seals the insulation coating.

The foam probably has more disadvantages than advantages

foam, perhaps has more drawbacks than advantages

The advantages of this material can be considered a low thermal conductivity, but the specific setting depends on the density and thickness of the material.

The negative qualities of the foam flammability refers to its melting and lots of poisonous toxic fumes.Therefore, in some Western countries, the foam is completely banned for use in construction.It is replaced by an extruded polystyrene foam, since this material is made without disrupting processes is poorly flammable and self-extinguishing.However, and Epps has a high toxicity in case of fire, and to its use in a home should be treated with a certain bias.


polyurethane foam - this material is sprayed, so its application can not take place without special equipment.If necessary, it can be sprayed in several layers, so it is often used for thermal insulation of houses located under the harshest climates.

The sprayed polyurethane foam creates a tight seamless coverage

sprayed polyurethane foam creates a tight seamless coverage

foam when applied fills all, even the smallest, cracks, cracks and voids, and expanding, forms a seamless airtight cover.Frozen layer has a greater density - you can walk on it, and it will not dent or crack.The thermal conductivity of only 0.027 W / mK and a water absorption of not more than 0.2% of its volume - which means that its insulating quality for any stored ambient humidity.

After solidification the excess material that can rise above the ceiling beams, can be easily removed with a sharp knife, which makes the material easy to fit under the general plane of the surface of the attic floor.

Another advantage of polyurethane foam is that it does not require auxiliary hydro and steam insulating materials for him, as it was originally already has similar qualities.

Video: review of modern insulating materials


relatively inexpensive material for thermal insulation of the ceiling can be called sawdust and small chips.Typically, these boards are used in combination, as part of the chip produces a porous insulation, and a layer of sawdust makes it more dense.