It has been proven that up to 60% of precious heat is lost through the attic floor. However, not every type of material is suitable for its thermal insulation. We will tell you in detail how to properly insulate the ceiling at the stage of building construction.
Content:
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Material selection
Thermal conductivity of materials of different thicknesses, mm
The ideal option for the ceiling would be a heater that has a minimum thermal conductivity, while having a minimum weight so as not to create an additional load on foundation. Another important requirement is incombustibility. It is also desirable that it is not able to absorb moisture. Otherwise, you will have to spend money on additional waterproofing.
But, unfortunately, even modern types of heaters do not have a complete set of these requirements:
Mineral wool
Styrofoam
Expanded clay
Ecowool
coal slag
Chips mixed with cement mortar
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| insulation | Bulk density, kg/m3 | Unit | -15 C | -20 C | -25 C | -30 C | -35 C | -40 C | -45 C | -50 C |
|---|---|---|---|---|---|---|---|---|---|---|
| Styrofoam boards, polystyrene | 40....100 | mm | 40 | 40 | 50 | 60 | 60 | 70 | 70 | 80 |
Mineral wool slabs | 200 | mm | 60 | 70 | 80 | 90 | 90 | 100 | 110 | 110 |
sawdust with lime | 300 | mm | 70 | 90 | 110 | 120 | 140 | 160 | 180 | 200 |
Expanded clay gravel | 500 | mm | 90 | 120 | 140 | 160 | 180 | 200 | 220 | 240 |
granulated slag | 500 | mm | 140 | 160 | 190 | 210 | 240 | 260 | 280 | 300 |
Fuel slag | 700 | mm | 170 | 200 | 230 | 260 | 280 | 310 | - | - |
Pumice | 600 | mm | 170 | 200 | 230 | 240 | 260 | 280 | - | - |
How to properly insulate the roof ceiling? To protect the premises from the penetration of cold, all joints of the floor are checked for cracks before starting work. They should be filled with foam, gypsum or a mixture of lime and tow. Wooden structures are coated with antiseptic compounds and fire retardant mixtures. When replacing the old insulation, the beams should be inspected, and if rotten boards are found, replace them with new ones.
It is also worth checking the ventilation system - ridge and cornice air vents. Unlike attics, a cold attic must be well ventilated. Otherwise, the beams and rafters will quickly rot as a result of the accumulation of condensate.
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Thermal insulation of wooden ceilings
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How to properly insulate the ceiling in a private wooden house? The main requirements for materials in this case are increased fire resistance and low thermal conductivity. When choosing price-quality, the best option is non-combustible slag or glass wool. It makes little sense to purchase more expensive stone wool. According to the main parameters, it is not much different from other types of glass wool.
Variants of insulation methods
As for moisture absorption, basalt wool fusing is required to protect against it. The cost of work together with fasteners will be simply sky-high. At the slightest mistake and the departure of the material from the overlap, there will be no sense from such spraying.
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Warming with mineral wool
Thermal insulation of the ceiling should consist of several layers:
- vapor barrier
- actual insulation
- waterproofing layer
Roof insulation
We will describe in detail how to properly insulate the ceiling under a cold roof:
- To protect the mineral wool from moisture, a layer of substrate should be laid under the beams (!) It is overlapped so that 5-6 cm of the material goes onto the wall. The second layer is placed between the boards of the crate
- In order for the insulation to lie as tightly as possible, when cutting it, pieces should be made slightly wider than the width between the beams
- All seams must be glued. This can be done with ordinary construction tape. When using foil material, it is laid with a protective layer down. An additional layer of vapor barrier in this case is no longer required.
- Rolled mineral wool is laid in several layers so that the center of the previous layer falls exactly on the seam of the previous one. A similar method is called a run-up of seams.. This material is capable of caking, so the total thickness of the layers should slightly (15% percent) exceed the required
- The corners of the house always freeze more, so an additional layer of mineral wool is placed along the walls. Its width is about 1 m, and its thickness is half the thickness of the laid layer.
- Eaves ventilation openings are not allowed to be closed.. To do this, pieces of plywood should be attached between the beams of the slopes.
- Mineral wool is easy to wrinkle, and its thermal insulation properties are lost. In order not to step on it during work, the crate (its width should be equal to the width of the material) is fixed simultaneously with the laying of the heat insulator and waterproofing
- To protect against moisture, an ordinary film of sufficient thickness is most often used. A more expensive material that can "breathe", removing steam without letting in moisture, is a diffuse membrane.
- The attic must be accessible for inspection. In order not to wrinkle the mineral wool when walking, a floor of plywood or boards is laid on top of the crate. It is allowed to use only revision passages - separate decks sufficient for passage. The rest of the insulation remains open
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Bulk insulation
Expanded clay layer
How to properly insulate a wooden ceiling with expanded clay or slag? We describe the main stages of work:
- In order to prevent moisture from slag or expanded clay from penetrating the wooden beams, a layer of vapor barrier is laid first. You can use both film and foil, penofol or glassine
- The vapor barrier must be thoroughly smeared with wet clay or clay-sawdust mass so that a layer of 2-5 cm is formed. Next, a layer of sand is applied. With the help of it, cracks are closed, which inevitably occur when the clay dries.
- Clay is able to protect the heat insulator layer from moisture penetration. However, it is still not worth abandoning the vapor barrier. After all, clay can crack over time.
- The next layer is directly slag or expanded clay. The thickness of such backfill is 15-20 cm
- To reduce the weight of the insulation, the heat insulator layer can be combined - add expanded clay or slag with a layer of mineral wool
- After leveling the backfill, a thin layer of concrete screed of 2-3 cm is poured
- Boards are laid on top of it to protect concrete from damage. If the attic will not be used, it is enough to make several revision "tracks" from the boards, along which it will be easy to walk for inspection
The reasoning that mice do not favor expanded clay is not entirely true. They are capable of destroying, in principle, any insulation. Over time, a sad fate awaits both mineral wool and polystyrene. Revisions should be periodically subjected to any of the heaters. The mouse also makes moves in expanded clay, although to a lesser extent. But to take out the pebbles, advancing, these animals will still be. The only way to protect against them is to periodically poison them and set traps.
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Insulation of rooms from the inside due to a shift in the dew point is undesirable. Moisture will be constantly present in the rooms. But in the case of the attic, this is the only way out. In this case, the material should be selected vapor-permeable so that the resulting condensate can be freely removed from the room.
The scheme of insulation of the attic floor
Another condition is the ability of the heat insulator to keep well on inclined planes. It must also have good soundproofing properties - otherwise the sounds of rain will penetrate the room.
The best choice in this case is slab insulation - mineral wool.
Just like in the previous cases, the heat-insulating "pie" should consist of 3 layers:
- vapor barrier layer
- insulation
- waterproofing
That is, the heat insulator must be protected from moisture from two sides - from below from the penetration of moisture rising from the room, and from above - from atmospheric.
- To ventilate the under-roof space, it is forbidden to lay waterproofing close to the roofing material. Otherwise, wooden structures will begin to rot, and metal will rust.
- If there are no too large differences in width between the rafters, mineral wool can be laid immediately between them. Otherwise, a removable crate will be required.
- With a width of openings between the rafters of 550-600 mm, it is not necessary to cut the slabs, therefore, when erecting a roof, this fact should be immediately taken into account
- Slabs of mineral wool or basalt wool will be held between them due to elasticity. They are laid out in a checkerboard pattern - so they will hold on stronger. But over time, the material becomes denser, and its elasticity decreases. Therefore, the plates need to be additionally fixed
- The vapor barrier film is attached over the boards with a construction stapler
- The last layer is finishing. For him, you need to prepare a crate. It can consist of a layer of plywood or moisture-resistant drywall
When using foam or expanded polystyrene, which is not able to "breathe", good ventilation is required to remove condensate from the room. Plus, due to the shrinkage of wood, gaps will form between the foam. The heat insulator has to be replaced. It should also be taken into account that both of these materials are not capable of absorbing noise - in the rain, the sound of its drops on the roof will be heard in the room.
Details on how to properly insulate the roof of the house, tells the video channel "How to build a house":
VIDEO: HOW TO INSULATE THE ROOF
How to properly insulate the ceiling: in a wooden house, bathhouse, attic, under a cold roof (Photo & Video)
ecowool: one of the varieties of mineral wool made on the basis of waste paper, into which an antiseptic and fire-retardant additives are introduced; from our point of view, the prefix eco- is just a publicity stunt; no matter how the manufacturers assure, it, like mineral wool, easily gets wet and is capable of shrinkage, therefore it requires hydroprotection; in properties it differs from mineral wool, perhaps only in price
Worked with Ecowool - a lot of inaccuracies
one of the varieties of mineral wool - NO
made on the basis of waste paper - YES
antiseptic - Boric Acid (all in the public domain, safe)
fire fighting - BURA (everything is in the public domain, safe)
shrinkable - NO
therefore requires hydroprotection - NO
differs in properties from mineral wool, perhaps only at a price - NO
They insulated the attic with clay and loose sulfur-containing slag - the effect of thermal insulation was noticeable, the house began to keep warm better and the bugs left their holes, wasps, flies and light bulbs stopped burning, but new blocks and beams gave a terrible cold falling from above. I am happy that I insulated the house and I have no doubt at all that our house will serve for many, many more years. With thermal insulation, jokes are bad, as well as with “sloppy” ventilation. Mineral wool gives “needles” for 100 years and no one uses the attic, but “sits down” quickly. Styrofoam is generally scary to think about, except for a while? I like sawdust with cement, thanks for the great idea! Good luck!