Methods for insulating an attic and flat roof with a foam-based coating, positive and negative properties of the shell, components for forming an insulating layer and the rules for their selection. Insulation of the roof with foam is the creation of a heat-insulating layer under the cladding of a pitched roof or on the surface of a flat floor. The dense material not only retains heat in living rooms, but also creates new exploitable areas. Together with a synthetic product, other elements are included in the composition of the protective coating, each of which performs a specific task. Information on how to select the right components and create insulating sheathing with them can be found in our article.
Features of roof insulation with penoplex
All roofs perform the same tasks - they protect the house from precipitation and retain heat in the living rooms. Penoplex, a Russian analogue of extruded polystyrene foam, which is popular in the West, copes well with these problems.
It is produced using an extruder - a special device through which a liquid mass is passed under high pressure. In Russia, the product is manufactured by the Penoplex company, which assigned the same name to the product. Domestic products compare favorably with their foreign counterparts by their low price.
The basis of the material is made up of small closed cells. The panels have a high density and withstand high mechanical stress. Thanks to these properties, the insulating layer can become the basis of an exploited site on a flat roof.
A heat insulator is sold in the form of panels of various sizes, the most popular is 0, 6x1, 2 m. The thickness of the plates ranges from 3-10 cm. If necessary, the sheets are stacked in two or three rows.
The material is mounted on the base in the following ways:
- Classic, in which the penoplex is placed under the waterproofing layer. It is allowed to walk on the ceiling only in special cases, so as not to damage the moisture-proof coating.
- Inversion, with bottom placement of moisture protection. Insulation and other materials form a rigid frame, which allows you to effectively exploit free areas. On the cover, you can place flower beds, tables, even walking areas.
Penoplex can be used for roof repairs. To do this, roll waterproofing is laid on the old coating, then expanded polystyrene panels, expanded clay and an outer moisture-proof layer are laid.
The attic roof is insulated with sheet material. The product is laid inside the frame or on top of it, depending on the preferences of the master. In this case, it is recommended to use panels with the lowest density, which are cheaper.
Advantages and disadvantages of roof insulation with penoplex
Thermal insulating "cake" based on this material has many advantages.
The advantages include the following qualities:
- Plates hardly absorb water. Even after full immersion in it, its mass increases by only 0.4%. After getting wet, the shape of the panels does not change.
- The product is very light and does not load the structure. Even dilapidated buildings can be insulated with it.
- Along the edges of the panels there are mills that facilitate joining.
- The repair time is shortened by the greater precision in the manufacture of panels.
- Blocks do not change their dimensions and geometry in heat and severe frost.
- They are easy to handle.
- The roof covered with foam can be turned into an exploited site. The product has a long service life.
- The material does not emit fumes that are harmful to humans, which is important for an exploited attic.
- On already built mansions, it is possible to insulate the roof with foam from the inside without changing the frame structure.
But even such a modern building material has a number of disadvantages:
- The insulator melts at high temperatures and emits toxic fumes.
- Attic roof repairs take a long time due to the need to cut samples in place.
- He is afraid of sunlight and quickly loses his strength. The protective shell should include additional layers for sun protection.
Roof insulation technology with penoplex
Insulation methods for problem areas depend on the roof structure. Flat ceilings are covered with sheets of increased density, which can bear a lot of weight. The panels are fastened from the side of the street. The attic roof is trimmed from the inside with slabs of low density. The option of foam insulation is chosen by the owner of the house, depending on the plans for the use of the upper floor or open area. For the protective layer, you will also need adhesives and special waterproof materials.
Tools and materials
The insulation is used in extreme conditions that only high-quality products can withstand. It is not possible to determine the actual characteristics of the product upon purchase, but it is possible to assess its condition after performing simple procedures.
Penoplex selection rules:
- Study the structure of the leaf carefully. The massif forms a large number of small granules that are barely visible. Large fragments indicate a violation of the manufacturing technology, sheets with such defects are saturated with moisture and lose their quality.
- Find the broken specimen and press down on the damaged area with your finger. Defective products will start to crack, because the thin walls of the cells burst. After installation, the blocks quickly collapse.
- Prefabricated panels are packed in plastic wrap. When buying, check that there are no gaps.
- The product label must contain basic information about the product: characteristics, dimensions, manufacturer, date of manufacture, etc.
- The sheets have the correct geometric shape. Deformations are not allowed.
- When insulating an attic roof, it is recommended to use Penoplex 31, Penoplex 31 C. These are inexpensive panels of low rigidity that cannot be loaded with a large mechanical load.
- High-strength samples Penoplex 35, Penoplex 45, withstanding a large weight, are laid on a flat roof.
For convenience, other markings are often used:
- Penoplex "Wall" with a density of 25-32 kg / m3 - for warming an inclined structure.
- Penoplex "Roof" with a density of 35-50 kg / m3 - designed for a flat operated roof.
Adhesives are necessary for fixing the foam to concrete floor slabs. Dry polyurethane adhesives Kliberit, Knauf, Ceresit are considered the most reliable. To prepare the solution, mix the powder with water according to the instructions for the product. You can also use tile adhesive. It has good adhesion properties and is much cheaper than special formulations.
When buying glue for penoplex, pay attention to the following points:
- The composition should not include substances that can dissolve penoplex - gasoline, kerosene, solvents.
- The glue hardening time is no more than 0.5 hours, so that it remains possible to move the panels until hardening.
- Calculate the amount of glue you need in advance, but buy more if there are uneven surfaces. It is also recommended to purchase extra packages for inexperienced craftsmen.
- The most convenient option is considered to be glue foam (for example, Penosil iFix Go Montage). It is stored in cylinders and is ready for use. The disadvantages of such a tool include the high cost, the need for a special device for squeezing out the solution, and rapid hardening.
- Check the purpose of the remedy. For flat roofs, outdoor adhesives are required.
- The tool reliably fixes the penoplex at any ambient temperature.
- Before buying dry mixes, check the storage conditions - they absorb moisture well.
To quickly cut sheets to the desired size, craftsmen use the following tools:
- Well-sharpened knives of appropriate dimensions. You can warm up the blade until reddening before work.
- Electric jigsaw. Indispensable when processing thick sheets.
- Nichrome wire, heated to reddening. Helps to cut a workpiece of any geometric shape. The ends of the finished product are perfectly flat.
Waterproofing performs a very important task - it protects the floor and the premises under it from rain and other precipitation.
For this purpose, the following materials are used:
- Films and special membranes. They are considered universal products that are designed to be used in various situations. For waterproofing a flat roof, you need products that are suitable for installation on a roof with a slight slope.
- Bituminous mastic. Most often it is applied on reinforced concrete floor slabs or on surfaces of complex shapes. The reliability of the coating will increase if it is used together with roll-up waterproofing. Instead of bituminous mastic, you can use acrylic, rubber, silicone.
- Roll materials. This is roofing material, brizol, fiberglass roll waterproofing. Stacked on flat surfaces.
- Liquid rubber. It is considered the best option for protecting reinforced concrete floors.
Thermal insulation of a flat roof with penoplex
Thus, flat reinforced concrete foundations are finalized. In this case, the waterproofing layer is located on top of the foam, which makes it vulnerable. It is allowed to walk on the roof, but it must not be used intensively, so as not to damage the waterproof sheathing.
The order of work is as follows:
- Remove debris from the roof, remove dust.
- Level the surface: cut off the protrusions, fill the cavities and cracks with cement-sand mortar.
- Treat the surface with a primer.
- Pour the base with cement mortar, ensuring a slope of 2-5 degrees.
- Further work can be carried out only after the layer has dried. The moisture content can be determined with a small piece of plastic wrap. Lay the canvas on the floor and secure with tape. After a day, check the condition of the screed under the film. If damp spots appear, the substrate is not dry enough.
- Prime the roof with a product that is compatible with the adhesive.
- Usually the screed is not waterproofed, but if desired, it is allowed to cover it with coating agents, for example, bituminous mastic.
- Glue the slabs to the screed. The product is applied to the penoplex, first with a smooth spatula, and then evenly distributed with a notched trowel. Leave the ends dry. Lay the panels tightly to each other with a horizontal offset so that there is no single joining line.
- Prepare a solution that is compatible with Penoplex and fill the base with a layer of 30-40 mm.
- After hardening, waterproof the base with roofing felt or other similar product.
Inversion insulation is used if it is planned to create an exploitable site on a flat roof. In order not to damage the fragile waterproofing layer, it is laid on the base first and covered with denser layers.
The work is carried out in the following sequence:
- Prepare the base as described above.
- Waterproof the slab using a coating or roll method. Glue the panels to the floor in the same way as for standard insulation.
- After the glue hardens, cover the penoplex with geotextile, and then with other layers, the composition of which depends on the purpose of the site. If the roof is unexploited, gravel with a thickness of at least 50 mm from fractions of 20-40 mm is poured onto the geotextile; if it is necessary to build a footpath, gravel is mixed with sand before laying, and paving slabs are mounted on top; you can create a green area on the roof. In this case, a drainage system of gravel with a thickness of 50 mm is formed on the geotextile, and an anti-root layer of soil substrate is poured on top, and then a vegetation layer.
Insulation of the attic roof with penoplex
There are several ways to modify a sloped roof, which differ in the placement of sheets in the frame. Most often, the panels are laid between the rafters. Other options involve attaching sheets to the top or bottom of the rafters, creating a continuous shell.
Before starting work, make sure that the roof structure meets the following conditions:
- The drainage system takes into account the slope of the roof.
- From the side of the attic, it is possible to fix a waterproofing film to the rafters to protect the wooden elements from moist air entering the attic from the living quarters.
- There is a gap of 40-50 m between the roofing and the membrane for ventilation.
Consider a brief technology for laying foam between the rafters. The advantages of this option are that the work can be performed at any stage of building a house without changing the roof structure.
Perform the operations in the following sequence:
- Cover beams and slats with antiseptics, fire retardants and pest control products.
- Cover the rafters from above with a waterproofing film and secure to the frame beams. Lay the cloth from the bottom up with an overlap of 15-20 cm on adjacent pieces and on the walls. Close the joints with reinforced tape. Do not stretch the membrane, provide a slight slack in the middle. The foil will protect the attic from water that can flow through the roof. Moisture is removed by an air stream passing from bottom to top through the gap between the film and the cladding. For this, special holes are made near the walls and skates.
- The membrane is also capable of passing moist air from the inside of the attic to the outside through the pores. To prevent the insulation from blocking the openings of the film, there should be a small gap between the foam and the panel.
- It is not necessary to install a waterproofing film if the roof is covered from above with bituminous tiles, which do not allow moisture to pass through. In this case, for safety reasons, only corners and cornices are protected.
- Mount the frame and install the cladding material, leaving a ventilation gap.
- If the house has been in use for a long time, the film is allowed to be laid from the inside of the attic.
- Cut blanks from the panels that fit snugly between the rafters.
- Install the panels between the beams so that there is a gap of at least 10 mm to the film. Fill the slots with foam scraps or polyurethane foam.
- Secure the panels in any way that can be used for slab insulation in a particular case. You can use dowels with a wide head, special corners or wooden slats.
- Cover the bottom of the penoplex with a vapor barrier film with an overlap of 15-20 cm on adjacent pieces and on the walls. Glue the joints with reinforced tape. The material should sag slightly. The membrane protects the lathing from humid air entering the attic from the lower floors. For waterproofing the roof of the attic, it is recommended to use a reinforced three-layer membrane or foil specimens.
How to insulate the roof with penoplex - watch the video:
To reliably insulate the roof, foam alone is not enough. The composition of the insulating layer must necessarily include waterproof products and means of protecting the main elements from damage. All components must be laid in a certain sequence, therefore, carefully study the technology of installing a heat insulator for a specific case before starting work.