Roof insulation with foam plastic is one of the most popular methods of thermal insulation in the construction of private houses today. Insulation of the roof of a wooden house using this material saves time and labor costs for the construction of a dwelling. This article contains some tips for insulating roofs with polyurethane foam.
Brief technical characteristics of foam plastics recommended for roof insulation.
Among the many foam boards produced by the industry, two names can be distinguished as the most suitable brands for thermal insulation of roofs - PSB-S-15 and PSB-S-25. Both of these roof insulation have found their application in the construction of country houses, change houses, warehouse and utility rooms.
Polyurethane foam boards are white in color and resist moisture and aging well. In addition, the material does not pose a biological hazard and successfully resists the effects of harmful microorganisms.
| Index | PSB-S-15 | PSB-S25 |
| Mass of 1 cubic meter. | Up to 15 | 15,1 — 25 |
| Compressive strength MPa, not less than | 0,05 | 0,1 |
| Bending strength, MPa, not less than | 0,07 | 0,18 |
| Thermal conductivity at 25 °C, W/(m K) no more | 0,042 | 0,039 |
| Self-burning time in seconds, no more | 4 | 4 |
The benefits of foam
Styrofoam has some advantages over other thermal insulation materials, such as isover roofing insulation.
Let's take a quick look at some of the main benefits:
- Large selection in trade organizations.
- Low cost.
- Ease of installation.
- Small weight, therefore, a decrease in the total mass of the building and a decrease in labor costs for insulation.
- Low water absorption capacity - if water gets on the insulating layer, it will not be absorbed, but simply drain off it.
- The level of thermal conductivity meets generally accepted building standards.
Depending on the type of roof, thermal insulation can be installed in different ways. Below we consider the specific points of insulation for different roofs.
Calculation of the required amount of materials
Before starting work on thermal insulation, it is required to perform a quantitative calculation of the roof insulation.
That is, you need to calculate how much such material. How roof insulation, namely - foam boards will need to be purchased. To do this, you need to measure the total area of \u200b\u200bthe roof and add some material for cutting.
For example, for roof insulation, N sheets of material are required, then you should buy N + 8 - 10 sheets. Such a margin is necessary so that in the event of an incorrect pattern of individual parts, you do not have to buy additional material and not waste time on this.
In addition, the remaining foam can always be used for ongoing roof repairs in the future (if the need arises).
Advice! If you organize the transportation of polyurethane foam from the trading organization to the construction site, take measures to preserve it.
- Protect plates from mechanical damage and significant physical exertion.
- If you carry out transportation in an open body, provide protection from possible atmospheric precipitation.
- At the construction site, provide a place to store material where the likelihood of damage to it is minimal.
The measures are not difficult, but they will make your life easier if unforeseen circumstances come.
Flat roof insulation technology
- Before starting the insulation of the roof with polystyrene foam, it is necessary to clean the roof surface.
- After that, the plane is covered with a layer of waterproofing material to protect the insulation. If you skip this step, water will seep into the insulation layer and reduce its insulating properties.
- Foam boards are laid on top of the waterproofing film. Here it is necessary to ensure that there are no large voids under the plates.In addition, it is necessary to ensure a tight fit of the sheets to each other.
- After laying the slabs, geotextiles are laid on top. This type of textile is intended to protect the roof from the harmful effects of ultraviolet rays, as well as to reduce mechanical stress on the insulation.
- Following the laying of geotextiles, it is the turn of backfilling gravel. The fraction of gravel should be 16/32. The thickness of the gravel layer is not recommended to be more than five centimeters.
In the absence of the possibility of using gravel, as an option, you can apply the roof with a concrete mixture or lay paving slabs. However, these methods significantly increase the cost and complexity of the work.
Mansard roof insulation device
The estimated service life of a mansard roof depends on a large number of factors that cannot be ignored.
So, for example, the heat engineering calculation of the roof must be carried out in accordance with the requirements of SNiP II-3-79 * "Construction Heat Engineering", and the entire roof structure must successfully withstand wind and snow loads. An important point is the slope of the roof.
Very often, attic space in houses is equipped for living quarters (mansards). In most cases, houses with gable roofs undergo such modernization, and here it is important to observe the minimum roof slope, which should be at least 25 degrees.
A roof with such a slope allows water to drain freely and tolerates wind loads well. The most important thing when building an attic is not to make the angle of inclination more than necessary, then the design will become unreliable.
Roof insulation with polyurethane foam is carried out according to the traditional scheme:
- Styrofoam sheets are placed between the rafters. In this case, it is necessary to achieve a thorough fit of the sheets to each other and to the structural elements.
- Roof waterproofing work is underway. For these purposes, special waterproofing films are used.
- Interior decoration of the attic room is being carried out. It all depends on the taste and financial capabilities of the developer. You can use plywood or plasterboard. Then putty surfaces and paint or wallpaper.
Important! When insulating this type of roofing, waterproofing is fastened to the lower plane of the rafters by means of battens. Reiki should be screwed with self-tapping screws or nailed with galvanized nails.
Some subtleties when working with foam insulation of roofs.
If the installation of the roof insulation did not go quite smoothly and gaps formed between the foam plates, then they must be carefully sealed. The same operation must be done in the places where the insulation parts adjoin the roof structures.
For these purposes, ordinary polyurethane foam is the best suited. Knowledgeable people recommend using foam for professional use.
Such foam is applied using a special gun, which allows you to seal all joints and interfaces with high quality.
Foam boards are most often attached to the surface by gluing. Less commonly, nails or dowels are used for these purposes.
Since adhesives can lose their adhesive properties over time, it will be better to combine gluing the boards with fixing them to nails or dowels. This will increase the reliability of the insulation.
During the work on the thermal insulation of the attic, the final stage of insulation is the design of the finishing layer of the finish. Often, wood-based materials are used for this, but another option can be considered.
This solution involves the design of the surface according to the principle of puzzles, for this a frame is constructed from suitable materials and pre-finished insulation elements are inserted into it.
Isn't it an original way to get, if necessary, to the internal elements of the roof? Here, of course, one can argue about the quality of thermal insulation, but that's another topic.
In general, polystyrene is a versatile and rather interesting material for thermal insulation. This is also emphasized in the rules for the installation of roofs with its use. The disadvantage of expanded polystyrene is, perhaps, only the need to protect it when working in bad weather conditions.
Roof insulation from the inside with the help of foam can be called the best solution for those who want to quickly and inexpensively insulate their home.
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