How to Build a Fire-Resistant House

In this article, we will begin a series entitled “How to Build a Sustainable Home.” First, we must mention the natural disasters that can affect modern dwellings. These include fire, water, wind, earthquakes, hail, landslides, and other factors that affect a house’s sustainability.

Fires are a common occurrence

This article will not discuss fires caused by human activity inside homes. A wealth of information, standards, and regulations already govern the use of fire-resistant materials and devices that prevent or slow the spread of fire. Now, we will discuss fire resistance, as fires are increasingly occurring in various parts of the globe. This phenomenon has both natural and external sources. This is usually preceded by factors that contribute to fires in open areas. The main factor is drought, which occurs due to a lack of natural precipitation. Several factors that coincide in time can also cause this phenomenon.

How are residential buildings and other adjacent structures exposed to fire? It is important to determine how and under what conditions residential buildings may be affected. Natural fires often spread by burning dry wood and other vegetation. When these materials dry out, they become highly combustible. At the same time, a large amount of heat is released in a short period of time in a given area. Additionally, wind carries combustible particles, such as branches and leaves, over long distances, creating new sources of ignition. Thus, buildings are exposed to high temperatures and small sources of ignition carried over long distances in a short period of time.

Fire Resistance of Building Structures and Materials

Now, let’s discuss the second source of fires and how to combat it. Burning particles carried by the wind are too small to be a source of fire themselves. However, they can easily ignite flammable objects. Since dry vegetation is absent in residential areas, flammable objects should be sought on the buildings themselves. The famous phrase, “The stability of a building is characterized by the stability of its weakest structure,” has not yet been refuted. This expression applies not only to fire safety, but also to seismic stability. We will discuss seismic stability in a separate article titled “How to Build a Seismic-Resistant House.” One of the first things in the path of burning particles spread by the wind is the roof of a house. Often, the roof is the weakest structure in terms of fire resistance. Roofs are often made of highly flammable bituminous materials. While bituminous materials sometimes surpass their counterparts in other properties, they lose out in this case. This does not mean that bituminous coatings are prohibited, but it is necessary to consider the surrounding area when choosing a material.

The first impact is a sharp rise in temperature over a short period of time. As mentioned above, bituminous roofs are susceptible to ignition from small sources of fire and even more so from large ones. What is the next possible target that should be eliminated? Wooden enclosing structures. Wood spontaneously combusts at temperatures between 330 and 400°C, especially with prolonged exposure. As we determined above, dry wood burns quickly. If the roof covering is made of non-combustible materials, it is difficult to cause spontaneous combustion of internal, load-bearing wooden structures. Therefore, some American states began using aerated concrete blocks as a barrier material. Of course, constructing such structures and connecting them to the main frame poses certain production difficulties. A reasonable question arises: Why not combine load-bearing and enclosing structures into one? This would solve several problems at once, simplifying the structure into a single-layer wall made of aerated concrete blocks. However, it is necessary to consider the increased mass of the entire structure due to the greater density of the material and the increased wall thickness. At the same time, we would achieve much better characteristics, not only in terms of fire resistance but also in terms of other equally important factors, which will be discussed in future articles in this series, “How to Build a Sustainable House.”

Window winter insulation

What exactly is a “warm window” installation, and what does it entail? First and foremost, the technology behind this insulation method applies to both composite-plastic and wooden windows. A vast majority of clients most often find online descriptions of different types of insulated glass, such as double-pane or triple-pane windows. And indeed, for houses with timber frames where wall thickness varies from 10 to 25 cm, this is the only viable option. To achieve a “warm window” installation effect, this option uses a vapor barrier membrane on the inside, polyurethane foam at the level of the window frame, and a waterproofing membrane on the outside. The outer membrane additionally acts as a wind barrier. This option provides a far greater hermeticity and protects the foam from external factors. However, in terms of increasing thermal resistance itself, these measures do not contribute to the resistance of this system. It exclusively adds durability to the thermal insulation material and significantly increases its service life. Therefore, this method can be described as an approved, recommended method of window installation.

Warm Window Installation

How exactly can the thermal resistance of the window frame joint be increased? Initially, it’s a key task to identify the weakest link in the joint. There is a significant number of variables in the system, such as installation foam, a heat-saving window frame with triple glazing, plastic, vinyl, or fiberglass. Any of the aforementioned elements may be at fault, and it is indeed difficult to single out a problem. However, there is one link that is often overlooked, and that would be a window slope. Typically, it is manufactured out of stone materials and has a fairly good thermal conductivity; moreover, the wall thickness by the slope is equal to the thickness of the window frame. In recent times, professionals in varying fields have begun to pay attention to these joints and insulate the slopes, which significantly increases the level of heat conservation. Nevertheless, there is a caveat: the insulation thickness slightly exceeds the space filled with polyurethane foam. Often, it is still possible to install no more than 3 cm of expanded polystyrene instead. With the improvement of heat-saving window designs, a reasonable question arises: How can the window frame connection be improved to correspond to the new level of efficiency that contemporary building materials provide?

Warm Installation Technology for Metal-Plastic Windows

Window winter insulation - Warm Installation Technology — Figure 1

This technology involves insulating the slope with thicker insulation material. To accomplish such a condition, the overall width of the ordered window must be adjusted to be thinner, while still taking into account the gap for the mounting foam. If the standard version uses 3 cm of insulation on the slope, the new version will use a 5 cm module on both the inner and outer slopes. First, it’s important to glue the extruded foam to the adhesive foam along all sides of the window frame, as shown in Figure 1. Then, install the window in the usual way, attached by means of the mounting foam. This step results in additional space for attaching 5

cm-thick foam to the slope, as shown in Figure 2. The most interesting aspect of this method is that, when using extruded foam, there is no need for an additional vapor barrier or waterproofing tape. This is because extruded foam is non-hygroscopic, meaning it does not allow vapor or moisture to pass through. To prevent wind from blowing through, apply polyurethane sealant to the joint between the window frame and the foam, inside and out, only once the slope is completed.

Warm installation of the base profile

All aforementioned methods apply to the side and top modules of the window junction. But how exactly can a similar result be achieved underneath the window junction where the window is installed? The process is, in fact, similar, but there are some nuances. The window is typically mounted on a base profile, to which the window sill is attached on the inside and the sill plate is attached on the outside. The space under the window sill and sill plate must be insulated. In accordance with the previously mentioned method, the entire surface of the window sill space must be covered with 3-cm-thick extruded foam and sealed with the adhesive foam as shown in Figure 3. Subsequently, in preparation for the process, cut holes with a diameter equal to the size of a given polypropylene pipe where the base profile rests. The main supporting elements are pieces of 3 cm high polypropylene pipe, equal to the circumference of the foam layer. These pieces are installed directly into the holes that were cut into the base profile. This will close off the entire lower part of the window sill, keeping it away from cold bridges. Both the window sill board and the sill will rest on an efficient layer of insulation. The second option is simpler; however, it implies a higher cost. Purchase a warm base profile with an increased height. This allows the window frame to be installed as usual, together with the base profile, directly on the stone base. Then, additional insulation is installed under the inner window sill board and the outer sill instead.

In summary, a well-performed, “true” warm window installation increases the thermal resistance of adjacent structures. It protects the installation foam from moisture, wind, and other external factors.

Author: houseplans360