Insulation of the attic roof of a private house

It is essential to insulate your private home’s attic roof in order to keep interior temperatures comfortable and lower energy expenses. The energy efficiency of your home can be significantly improved by using proper insulation, whether you’re building new or retrofitting an existing one.

In the winter, attic insulation helps to create a barrier that keeps heat inside, and in the summer, it helps to prevent excessive heat buildup. Over time, this helps to reduce your heating and cooling expenses while also improving the comfort of your living areas.

The design of your home, your budget, and your climate all play a role in selecting the best kind of insulation. Mineral wool, fiberglass, cellulose, and spray foam are examples of common insulation materials. Each provides varying degrees of thermal resistance (R-value) to meet various needs.

It’s critical to evaluate your attic space for possible air leaks, moisture problems, and existing insulation before beginning the insulation process. By taking care of these issues in advance, you can make sure that your insulation efforts are successful and durable.

Features of calculations

A complex formula is used to calculate the thermal resistance of a roof with single-layer insulation. This formula considers a number of factors, including the technical properties of the insulation, the building’s need for thermal protection, the location’s climate, standards for the microclimate indicators, and the purpose of the space. When creating a project, professional architects utilize the formula.

The foam-filled interior attic insulation

It is sufficient to apply the useful advice of the builders rather than performing such computations for regular developers:

  • For the southern regions of our country, the thickness of mineral wool or foam should be within 10 cm;
  • for moderate climatic regions, the thickness of the insulation is at least 15 cm;
  • for the northern regions, the thickness of the insulation is at least 20 cm.

It always indicates that a heater made of mineral wool or polystyrene is being used because these materials have the lowest thermal conductivity of any building materials.

The insulation plan for the loft

The calculator of the attic

The relationship between the insulation’s thickness and thermal conductivity

For every homeowner, having a properly insulated attic roof is essential to comfort and energy efficiency. This post discusses useful strategies and important factors to take into account when insulating your attic. It will also assist you in selecting the best insulation, navigating installation methods, and optimizing insulation to save energy expenses and keep your home comfortable all year round."

Which heat to choose

At the moment, mineral wool and foam heaters are the two most widely utilized types. Mineral wool can be rolled and pressed, either covered in foil or not. Foam can be regular or extruded, and it can have side locks or not. Furthermore, different companies produce products with slight variations, but these distinctions don’t have a major impact. The decision of which insulation to choose is a challenging one. Read the comparative operational characteristics of both materials to help you make the best choice possible.

Foam or mineral wool

Accurate comparisons are nearly impossible to make because there are too many variables influencing the indicators. The data in the table is average; small deviations have no discernible impact on the final characteristics.

Table: Comparing the properties of foam and mineral wool.

Ecological sustainability and fire safety

The answer is clear-cut: no, each insulation will provide high-quality insulation as long as it is installed using the suggested technologies. And vice versa—no insulation will perform its functions if serious mistakes were made during the work. Not only will the attic be frigid, but an increase in humidity could seriously harm wooden roofing structures.

There are two ways to insulate an attic roof: either from the inside after the roof has been installed, or from the outside before roofing materials are covered on the rafter system. The first scenario has serious drawbacks since there’s a good chance of wetting the insulation, which would have disastrous effects. Regarding this, we won’t take into account the option and will merely provide detailed instructions for insulating the attic roof from the inside out. For instance, think about using foam or mineral wool as the materials.

There are drawbacks to outdoor insulation.

Step -by -step instructions for insulation with mineral wool

Determine how much mineral wool is needed, then make the purchase. You’ll need measuring tools, an electric drill, a sharp knife, and a stapler for work. We will take into consideration the possibility of installing insulation using metal profiles, which allow for faster work and improve the functionalities of a warm roof.

We use mineral wool to warm the attic roof.

Step 1: Determine how far apart the rafters are from one another. A cut-off piece of mineral wool should be slightly wider than the measurements; this will ensure a more snug fit of the material to the rafters. Allow for a margin of about 2-3 cm.

The space between the rafters has frozen.

Roll out a roll of mineral wool and allow it to return to its factory thickness over a few minutes. Make tiny cuts with a sharp knife in the mineral wool using a roulette or a folding construction meter.

There are minor incisions made

Step 2: Cut a cotton piece to the appropriate size. If you don’t have a long ruler, you can use a correspondingly sized piece of the OSP plate.

A fragment of mineral wool is severed.

Step 3: Draw on the line’s rafters. The line’s thickness should match the distance between it and wind protection. Future brackets for fastening planks from a metal profile will be fixed in this line. Mark the rafters at intervals of approximately 40 centimeters. Special brackets are fastened to these locations to secure metal profiles.

The distance between each mark should be about 40 cm.

Step 4: Screw the components to the rafters, making sure they are all positioned on the same line so that the brackets’ adjusting holes line up. Use the second self-tapping screw to secure the components once the precise location has been determined.

Dragging the fastener component

The bracket is in an aligned position.

The second self-tapping screw secures the bracket.

Vital. The spacing between the ends of the brackets and the roof should be the same as the total of the two mineral wool layers’ thicknesses.

The bracket mounting procedure

Step 5: Use brackets to attach metal profiles. Verify that the metal profiles are positioned correctly by using a long rail or rules. There are issues; fix them by unscrewing the screws, moving the object, and tightening the marking once more.

Putting in a metal profile

Every rail is put in place.

Disassemble the rails after they have all been installed and examined. They get in the way of the mineral wool pieces being installed.

Step 6: Correct its position and insert a cut piece of mineral wool between the rafters. Pay close attention to ensure there are no gaps; Minvata did not distort her lies in any way. Heat the roof in the same manner over the whole attic. The highest point that can be reached from the ground without the aid of forests or ladders.

Between the rafters is inserted a piece of mineral wool.

The remaining mineral wool fragments are placed

Step 7: Install a 5-cm-thick roll of mineral wool across the rafters after rolling it up. This layer, which is 10 cm thick, will seal up all the cracks. Rub the canvas gently where the brackets are to be installed.

A roll of mineral wool is spread out over the rafters.

Where the bracket is installed is where the insulation leaks through.

Step 8: Install the metal profiles, which will support the two glass wool layers simultaneously. Remove the protective paper and apply bilateral tape.

Installing metal profiles repeatedly

Bleeding two-sided tape

Step 9: Get the membrane ready, stretch it carefully over profiles, and adhere it to the tape with glue. Be mindful that the membrane extends precisely through the whole surface when stretching.

A membrane bleeding on a double-sided tape

Step 10: Allow the membrane overlaps to cool. The overlaps should be about 10 centimeters wide.

With tape, the overlaps are sealed.

A tiny roller is used to roll wool.

Vital. Moisture will penetrate the insulation less deeply the tighter the membrane. As a result, there will be less thermal conductivity and warmth in the attic rooms.

It is also advised to use tape, staplers, and sealant on the premises’ corners. It is now time to finish the roof.

A stapler is used to seal the angle.

Additionally made use of tape

The attic space is prepared for completion.

Mineral wool prices

Mineral wool

Step -by -step instructions for insulation with foam

Foam heating offers benefits as well as drawbacks. Numerous factors impact the ultimate decision, which each developer must make for themselves. Two layers of foam are used for insulation, and the sheets are arranged in a checkerboard pattern to reduce heat losses. You’ll need mounting foam and a small-toothed manual saw or sharp knife for the task.

Step 1: Install the foam sheet between the rafters after cutting it to size. The sheet should be 0.5–1.0 cm larger than the rafters’ spacing apart. Use mounting foam to secure the sheet for wooden structures. She seals all the gaps hermetically in addition to tightly grasping the insulation. Install the first foam layer across the whole roof, following the same algorithm. Another benefit of using mounting foam is that it greatly speeds up and facilitates the laying of foam slabs.

Measured is the separation between the rafters.

Using a hacksaw to cut foam

Vital. If there is a steam shield between the rafter system and the roofing, then leave a space of two to three centimeters between the sheets and the membrane. This is essential for natural ventilation; otherwise, condensation builds up and the rotted wooden components of the rafter system occur.

When a vapor barrier is present, there is a tiny space between the foam layers.

Using a sharp mounting knife, carefully cut off any excess foam after it has solidified.

Step 2: Prepare the foam; it should be roughly the same size and quantity as the first layer. Place it in between the rafters, closing the joints and remembering to arrange the sheets in a checkerboard pattern. This is an extra precaution; mounting foam is already firmly inserted into the joints.

The second layer of foam (fitting) is being laid.

Vital. The polystyrene layers ought to fuse together as firmly as feasible. Due to air convection, thermal losses will greatly increase if there is a gap between them. And the comfort of attic rooms will unavoidably suffer as a result.

It is advised to apply foam to the edges and seams of the first layer’s sheets prior to installing the second layer. It is best to let the foam stand for approximately five minutes before adhering the top layer of foam. The foam completely loses its properties, does not gain volume, and cannot hold foam sheets together if you press it without providing excerpts.

Foam for installation is used.

Foam at the heater slab junction point

Prior to applying the second layer, the foam must be left for roughly five minutes.

Step 3: Place the second layer of foam in place and completely fill in all of the cracks around the perimeter with foam.

Sensible guidance. Dive the bulk of the sheets if you are unsure about how well the second layer of foam will adhere to the first.

There are spaces around the edges of the second layer’s sheet that are propen

Step 4: Install insulation between the rafters and the Mauerlat adjustment location. This crucial rafter system node can support the heaviest loads. One more feature, though, is that it alters in size and arrangement throughout the summer and winter. This indicates that while the oscillations’ amplitude is tiny, it is still enough to allow moisture to pass through because individual components are always in motion. Work very carefully in these areas, taking care not to miss any foam, as it perfectly seals the junction while allowing the elements to change linear dimensions.

Pay close attention to the location of the rafters adjacent to Mauerlat.

A very important step in the construction of attic spaces is the foam roof insulation; deviating from the advised technology can have disastrous results. Errors cause wet, warm air to condense beneath the roofing cake, soaking wet lumber. Two factors contribute to how slowly drying happens. The first is that water is absorbed by the tree far more easily than it evaporates. Second, the nearly total lack of natural ventilation causes the drying of wooden structures to proceed even more slowly.

Using polystyrene for roof insulation is an essential step in the building of attic rooms.

And the most important thing. The processes of decay occur in a closed space, they cannot be visually detected in the early stages. At best, over time, wet spots will appear on the finish wall decoration. At worst – problems will be found after deformation of the rafter system. During the repair, you will have to dismantle the exterior decoration of the attic rooms, remove the insulation and make an audit of the roofing system. If the rafters are not subject to repair, then their replacement is much more expensive than the construction of new. Keep this in mind and is very responsible for insulation of the attic roof of a private house.

Foam prices


Your home’s attic roof needs to be insulated if you want to keep your comfort level and energy efficiency year-round. You can create a barrier that keeps your house cool in the summer and warm in the winter by properly insulating this area.

Selecting the proper insulation material is essential. Take into account variables like the local climate, the R-value (a measurement of thermal resistance), and the amount of space that can be used for insulation. Common materials include rigid foam boards, fiberglass, cellulose, and spray foam; each has advantages and disadvantages with regard to performance, ease of installation, and cost.

For installation to be effective, care must be taken. To stop heat from escaping through uninsulated areas, or thermal bridging, insulation needs to be installed uniformly and without gaps. Sealing air leaks around vents, pipes, and chimneys increases the effectiveness of the insulation even more.

Long-term performance of your attic insulation depends on maintaining it. Frequent inspections can assist in identifying any problems, such as deteriorated insulation or moisture buildup. Furthermore, you can eventually save a lot of money on heating and cooling expenses by upgrading your insulation as necessary and making adjustments to meet changing energy efficiency requirements.

Video on the topic

Warming of the walls and ceiling of the attic floor!

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What do you think, which element is the most important for a reliable and durable roof?
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Alexandra Fedorova

Journalist, author of articles on construction and repair. I will help you understand the complex issues related to the choice and installation of the roof.

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