For a private home to remain comfortable and energy-efficient all year long, insulation of the roof is essential. Warmth in the winter and coolness in the summer are maintained in a home with a well-insulated roof. To get the best roof insulation, there are a few practical ways to do it.
Utilizing insulating materials like cellulose, mineral wool, or fiberglass is one of the most widely used techniques. These components are positioned in the space between the roof structure’s rafters and joists. They efficiently retain heat, keeping it from escaping through the roof and eventually lowering energy expenses.
Spray foam insulation is another method that is becoming more and more popular. Using this technique, a polyurethane foam is sprayed directly onto the roof deck’s underside. With its ability to expand to fill voids, the foam creates a continuous barrier that offers superior thermal insulation. Its high R-value per inch, a measure of thermal resistance, makes it well-known.
Another practical choice is reflective insulation, particularly in areas with hot climates. Underneath the roof rafters are reflective insulation boards or foil sheets used for this type of insulation. It functions by deflecting radiant heat from the home, lowering the temperature inside and lessening the strain on air conditioning units.
Sustainable options for individuals thinking about their impact on the environment include natural insulation materials like hemp, recycled denim, or sheep’s wool. These materials are environmentally friendly and renewable, and they offer good insulation.
The optimal insulation technique is determined by a number of variables, including the house’s unique roof structure, climate, and financial constraints. Homeowners can improve comfort, lower energy costs, and contribute to a more sustainable living environment by choosing the appropriate insulation approach.
- What is the best way to insulate a roof in a private house?
- Pitched roof
- Flat roof
- Summary comparative table of insulation
- What is the best way to insulate a roof?
- Installation technology
- Video on the topic
- Penoplex on the ceiling!!! Insulation of the ceiling with extruded polystyrene foam in a private house!
- ✅ HOW TO EASILY AND QUICKLY INSULATE A ROOF WITH YOUR OWN HANDS | INSULATION OF A ROOF WITH EPS | INSULATION OF THE ATTIC
What is the best way to insulate a roof in a private house?
The following materials are used to insulate the roof:
- expanded clay;
- Styrofoam;
- extruded polystyrene foam;
- rigid polyurethane foam;
- PPU slabs;
- linen;
- ecowool;
- glass wool;
- basalt wool.
Pitch and flat roof types must be considered in order to provide an unbiased evaluation of the insulation technologies and materials used. First of all, their approaches to performing thermal insulation work differ. Second, and this is crucial: only if an attic is built in the attic space is it recommended to insulate a pitched roof. If it is absent, even a kindergarten student will be able to comprehend that the costs are lower because the ceiling area is substantially smaller than the roof surface.
Thirdly, compared to a pitched roof, a flat roof can support tens of times more weight. After all, when insulating buildings with a flat roof, weight loads can be disregarded because the system is based on reinforced concrete floors rather than a system of wooden beam rafter systems.
Typically, ten or twelve criteria are used to select the type of insulation. Nevertheless, many of them are not very important for roofs. Take thermal conductivity, for instance. One of the most crucial indicators if you wish to keep the room’s volume intact while insulating (living room, bedroom, bathroom, balcony, etc.). and has no bearing on any kind of roof; the thickness of the thermal insulation layer increases without being noticeable. As a result, we employ the following minimal set of criteria in our analysis to decide how to insulate a house’s roof:
- the price of the issue (includes the cost of materials, and if it is not possible to do the work yourself, the cost of installation) is the most important indicator when carrying out any construction and repair work;
- durability – allows you to evaluate the effectiveness of financial investments;
- the complexity of the work is an important criterion for that category of the population who strives to carry out all construction and repair work independently in order to save the family budget.
Pitched roof
Articles about the technology used to insulate pitched roofs using nearly all readily available thermal insulation materials are available on our website. However, this does not imply that it ought to be done. We will therefore examine each insulation in turn.
Clay that has expanded. Expanded clay is thought to be a cheap way to insulate any part of a building. Is that right? Let’s investigate.
This is true if we use the price of one meter three of material as our base. And it’s this indication that deceives a lot of customers, giving ceramic pellets a respectable amount of sales.
The contrary is actually true: due to the granules’ high heat conductivity, the insulating layer must be at least three times thicker than it would be with the same basalt wool. This not only eats up any potential savings but also raises the estimated cost of construction and repair work. This is sufficient to forgo expanded clay when covering the roof. However, there are three other factors about which silence is impossible.
- Expanded clay should be poured onto the roof with a thickness of 35-40 cm. Average specific gravity of granules 400 kg/m 3 . This means that about 14 tons of insulation will be pressed on top of a house with an area of 55-65 m2.
- The roof can be insulated with expanded clay only over a solid wooden deck mounted on top of the rafter system (details can be found here). For this you need boards or OSB. Additional material will have to be purchased for 20.0-30.0 thousand. rub., which increases the cost of work by approximately 2.0-2.6 times.
- A counter-lattice needs to be installed on top of the insulating layer, which increases the cost of insulation.
In summary, expanded clay should not be considered a viable insulation material when it comes to pitched roofs.
Styrofoam. The Stockholm Convention forbids the use of expanded polystyrene in attic roof insulation. However, issues with a cold attic’s thermal insulation also exist. It is not possible to install foam boards in between rafters. The cause is a variation in the wood’s linear dimensions, which are used to make the rafter system.
The rafters swell during operation due to seasonal variations in temperature and humidity at the end of autumn, and by the end of summer, they have dried to a humidity of 8–12%. Variations in size can reach up to 3 cm (based on rafter thickness). Consequently, cracks appear that render any roof insulation work useless.
The instructions for using foam plastic to insulate the roof account for this issue; the material is installed over the rafters on a flooring composed of unedged boards (the detailed procedure cycle is provided here). However, because of the need to insulate the overhang—the space between the building’s wall and the roof’s finishing layer—and the cost of flooring materials, this method of work dramatically raises the cost of thermal insulation. For example, the cost of insulating a single meter of roofing increases from 140–185 rubles to 235–305 rubles (not including vapor barriers and installation work).
The material’s 30-year lifespan, which is extremely short for a roof, is a drawback. Many people also overlook the fact that polystyrene foam resonates, which makes it unlikely that you will be able to sleep under a roof made of corrugated sheets or metal tiles when it rains.
In conclusion, polystyrene foam should only be used as an insulation for pitched roofs if no other options are available.
Polystyrene foam extrusion. The same technology used for polystyrene foam installation is used to install insulation composed of extruded polystyrene foam. Due to the high cost of insulation work, the material is not considered a viable option for roof insulation because of its considerably higher price.
Polyurethane foam that is rigid. The only real drawback to PPU insulation is the high labor costs (between 1000 and 1200 rubles per square meter). Because of this, cutting the process’s cost by doing it yourself is not an option. To do this, you’ll need specialized tools capable of high-pressure spraying as well as hands-on practice. If you do the spraying yourself, you can use disposable kits, but the roof will literally turn golden because one kit is sufficient for 10 square meters, and they are not inexpensive.
Don’t forget that the rafter system needs to be sheathed with boards or OSB boards underneath rigid polyurethane foam insulation. And this results in extra expenses of between 240 and 280 rubles per square meter.
In conclusion, insulation is out of reach for the middle class of people. This is a luxury enjoyed by the wealthy.
PPU flooring. It is also more costly for a private home to insulate a sloping roof with PPU slabs. First off, installing flooring beneath both the insulation and the polystyrene foam is necessary. Insulation is an expensive material.
In conclusion, PPU slabs are not advised for the insulation of pitched roofs due to their high cost, even though there are numerous benefits to using them (a comprehensive list of the material’s benefits and drawbacks can be found here).
Linen. With simple technology, you can attach natural flax insulation between the rafters with your hands. The thermal insulation layer has a minimum 50-year service life. The cost—at least 550 rubles per square meter—is the deterrent to use.
In conclusion, only the wealthy can afford linen insulation because of its high cost.
Ecowool. Producers of low-cost, green cellulose fiber insulation actively market their products for use as insulation for roofing. With one exception—durability—we can almost entirely agree with them. Ecowool shrinks or compresses quickly on vertical and incline surfaces, creating wide gaps that allow cold air to enter.
In conclusion, ecowool is not a suitable material for roofing insulation due to its shrinkage.
Be aware that sawdust is utilized in rural areas for ecowool insulation technology. There aren’t many expenses. However, some owners dislike the constant addition of sawdust needed to compensate for the insulating layer’s shrinkage. Consequently, the StroyGuru website editors. In these situations, Kom suggests insulating the ceiling from the outside rather than the roof with sawdust.
Glass wool. Mineral fiberglass insulation is inexpensive, easily installed, and has a good heat-retaining capacity. The short service life of glass wool is the issue; it turns into dust after 25 to 30 years and is challenging to remove without full body protection.
In conclusion, it is best to stop using glass wool because of its short service life.
Wool made of basalt. The only kind of thermal insulator that completely satisfies all of the needs of the customer when selecting roofing insulation, including low thermal conductivity, affordable pricing, extended service life, and straightforward thermal insulation technology.
In summary, there is no alternative to basalt wool for insulating roofs.
To sum up, you can use a variety of materials to insulate your roof:
- polystyrene foam;
- extruded polystyrene foam;
- hard polyurethane foam;
- PPU slabs;
- flax;
- basalt wool.
Only basalt wool can meet all of the needs of the consumer from the list above. The disadvantages of other thermal insulation materials are mostly related to their high installation and construction costs.
Flat roof
The selection of thermal insulation materials is more limited for flat roof insulation. This:
- expanded clay;
- extruded polystyrene foam;
- PPU slabs;
- basalt wool.
The cost of thermal insulation work is largely unaffected by price when it comes to flat roof insulation; all materials are roughly equal in price, with the exception of polyurethane foam boards, which are the priciest. In this case, the technology of the roof itself determines the kind of thermal insulation material to use. For instance, expanded clay and basalt wool work well for roofing felt, and extruded polystyrene and polyurethane foam slabs should be covered with flat slate after the surface has been filled with heated bitumen.
In conclusion, after deciding on the kind of roof, insulation needs to be chosen, and cost indicators need to be examined.
Summary comparative table of insulation
An overview is provided by the analysis above. We outline the key operational and technical indicators of insulation for better understanding.
Table 1 lists the primary attributes of roof insulation.
Insulation / Characteristics | Thermal conductivity, W / (m × ° K) | Service life, years | Density, kg / m3 | Cost |
---|---|---|---|---|
Rigid polyurethane foam | 0.024-0.035 | 30 | 20-80 | ***** |
Slabs PPU | 0.028-0.030 | 50-60 | 40-160 | **** |
Foam plastic | 0.037-0.043 | 20-30 | 8-35 | ** |
Extruded polystyrene foam | 0.028-0.034 | More than 50 | 28-45 | ***** |
Basalt wool | 0.038-0.047 | More than 50 | 30-300 | *** |
Expanded clay | 0.10-0.18 | 40-60 | 210-500 | *** |
Ecowool | 0.032-0.041 | More than 50 | 30-75 | ** |
Linen mats | 0.034-0.043 | 50-75 | 25-50 | ***** |
Glass wool | 0.035-0.052 | 15-25 | 15-150 | *** |
Sawdust | 0.07-0.10 | More than 100 | 200-270 | ** (*) |
- ***** – high;
- **** – above average;
- *** – average;
- ** – low;
- * – for free.
The following table validates the conclusions drawn in the preceding section:
- There are no alternatives to basalt wool for a pitched roof. As an exception, exotic lovers with money can choose environmentally friendly flax or popular hard polyurethane foam;
- Expanded clay, extruded polystyrene foam and basalt wool are suitable for a flat roof. You can also use PPU boards, but it is expensive.
What is the best way to insulate a roof?
We have already provided an answer to the query of how to insulate a private home’s roof above. However, people who visit the website want to know how to insulate a bathhouse, garage, and log home.
Log home. A pitched roof covers a wooden frame. As a result, basalt wool has no rivals.
Garage. A garage roof is usually flat. Thus, basalt wool and expanded clay can be used there for about the same price.
A bath. The roof of a village bathhouse is uninsulated, as anyone who has ever used one will attest. Steam can only be retained by ceiling insulation. The work "Rules for choosing insulation for the ceiling" demonstrates how to do it.
To insulate a roof in a private house effectively, choosing the best method depends on factors like climate, budget, and roof structure. Options include traditional fiberglass batts for their affordability and ease of installation, though they can be less effective if not installed properly. Spray foam insulation offers excellent thermal resistance and seals gaps tightly, ideal for preventing heat loss. Reflective or radiant barriers are great in hot climates, reflecting heat away from the house. For those concerned with environmental impact, natural materials like sheep"s wool or cellulose insulation provide sustainable options. Ultimately, the best choice combines effectiveness, cost-efficiency, and suitability to the specific climate and structure of the house.
Installation technology
There is a specific technology designed to insulate a pitched roof for each type of insulation. We will give a brief explanation of each type of thermal insulation material’s application process for high-quality insulation.
Sawdust and expanded clay. OSB or edged boards are used for the exterior flooring of the rafter system. To create cells for bulk insulation, a beam is attached horizontally along it (details are in the article "How to properly insulate a roof with expanded clay?").
PPU boards, foam plastic, and extruded polystyrene foam. These insulating materials use the same technology:
- a flooring is mounted on top of the rafters (it may not be as dense as for expanded clay);
- a vapor barrier film (type B) is attached to the flooring;
- the sheathing is stuffed;
- insulation is installed;
- the thermal insulation layer is covered with a windproof film (type A);
- the counter-lattice is stuffed.
Polyurethane foam that’s rigid (PPU). Above the rafter system is an OSB decking that has been sprayed with liquid polyurethane foam.
Ecowool. Making closed cavities to blow in ecowool presents the biggest challenge in roof insulation. The paper "Review of Ecowool insulation" explains the subtleties of the technology.
Glass wool. A cord is used to secure the fiberglass insulation between the rafters. Here’s where you can see the proper way to do it.
Woolen linen and basalt insulation. The two types of insulation are sandwiched between the rafters. The article “Insulating the roof of a private house with mineral wool” goes into great detail about the technology.
For flat roofs, specialized technologies have been developed. Vapor barrier film is installed on the top floor of private residences (see Fig. no. 2).
Extruded polystyrene foam, polyurethane foam, or basalt slabs are placed on it in two layers with an offset in accordance with the brickwork principle; this is indicated by the number 3.
On top of the slabs, a two-layer screed composed of flat slate (4) is installed, and everything is then filled with heated bitumen.
Expanded clay insulation for flat roofs uses a marginally different method:
- a layer of expanded clay sand about 5 cm thick is poured;
- granules 35-40 cm thick are poured onto the sand;
- roofing felt is laid on the poured expanded clay, the joints of which are glued with hot bitumen.
For comfort and energy efficiency, your private home’s roof insulation is a critical decision. There are various efficient approaches to take into account, each with unique benefits and factors to take into account.
Known for its superior thermal performance, spray foam insulation forms a seamless barrier that keeps out air and heat. Because it can be applied quickly and conforms to irregular shapes, it is a popular choice even though its initial cost is higher.
A more conventional method that offers good thermal resistance at a lower cost than spray foam is the use of fiberglass rolls and batts. Although installation is simple, for best results, make sure all edges are properly covered and sealed.
Another choice is rigid foam boards, which are highly valued for their high insulating qualities per inch of thickness. They are ideal for do-it-yourself projects because they are lightweight and simple to cut. To avoid thermal bridging, however, correct installation is essential.
In order to lessen radiant heat gain, reflective or radiant barrier insulation is usually placed in attics. It functions by reflecting heat away from the house. Although useful in some climates, it performs best when paired with other forms of insulation to address various heat transfer pathways.
The best option will ultimately depend on a number of variables, including your roof’s particular design, budget, and climate. A professional insulation contractor can guide you through these choices and make sure your selection satisfies your short- and long-term energy efficiency objectives.