How to effectively insulate the house

In this article, we will look at the main options for upgrading each thermal component, but it is important to apply an integrated approach to the whole house so that everything works together.


You will need to consider the risks associated with changing the structure of your property and be careful to avoid cold places (which can cause condensation), as well as make the necessary changes to your heating systems and ensure adequate ventilation.


Without a proper assessment of the properties, it is impossible to accurately predict what energy savings each particular insulation technology will provide. This is due to the fact that houses vary greatly in shape, structure, location, condition and equipment.


Even seemingly homogeneous buildings, such as terraced houses, could be rebuilt or expanded in various ways. In addition, housing and energy consumption patterns will also vary significantly. But the basic principles remain the same. Here's how to approach environmental modernization.


Before you start working, do not update the insulation until you have completed basic maintenance. A well-maintained building will work relatively efficiently, while a wet wall transfers energy quickly, so it's important to make sure your property is dry and defect-free.


Roof insulation.

Heat rises up, so a large amount of energy can be lost through voids in the attic. If your house has a sloping roof and a flat ceiling at the bottom, leaving the attic uninhabited, adding insulation should be simple, cheap and cost-effective.


As a rule, the goal is to lay 270 mm of mineral wool between the logs (and possibly above them). However, there are a few things to keep in mind:


Do not make the common mistake of forgetting to insulate the attic hatch.

Never block the hood - in most cases it should remain free to ensure sufficient ventilation and thus prevent condensation.

The attic space will slide past the thermal envelope of the house, so it may be necessary to insulate the round cold water tanks to prevent them from freezing.

A little isolation is not enough, as it takes a lot to get a little more work done. It may turn out that it is not worth pouring insulation if, say, we already have 150 mm of mineral wool.

You may want to consider other products such as sheep wool due to its inherent durability, or options such as blown cellulose if access to space is difficult.

If the roof has already been converted into a living space, any thermal replenishment must be integrated into the sloping ceilings, which can be a more difficult task. In most cases, insulation is added between the rafters, but an air gap must be left above it to ensure sufficient transverse ventilation.


This can be supplemented with a layer under the rafters, but this, of course, will reduce the height above the head. To minimize this effect, a high-performance insulation made of rigid foam is usually used here.


Insulation of floors on the ground.

Massive ground floors are difficult and sometimes impossible to insulate. It is usually impractical to dig them out and add insulation under them, while adding insulation from above will raise the floor level and probably cause problems at the door and stairs. Instead, it is worth investing in a good quality primer, which in most cases will cope with its task.


If there is enough space and access, suspended single-storey wooden floors can be processed from below. Alternatively, the floorboards can be raised and insulation can be installed between the beams from above.


This should be done very carefully if you are dealing with an old wooden floor, as it can be an important element of the character and value of your home. It is also important to ensure that the ventilation openings on all sides of the room are clean and free, as this strategy restricts natural ventilation. If the air flow in the floor is insufficient, this can lead to rotting of the beams.


Efficient windows.

You may be surprised to learn that more energy is often lost through the cracks around the window frames than through the glass itself.


With this in mind, maintaining and upgrading existing units is always a reasonable plan. In many cases, existing frames can be repaired and preserved, deeper double-glazed sashes can be inserted, and new seals can be installed.


Even the addition of thick curtains or well-fitted blinds will significantly reduce heat loss. If a single-glazed window has a heat transfer coefficient (a heat loss indicator at which lower values mean better values) of 4.3 W/m2K, investments in heavy curtains can reduce it to 2.5 W/m2K or even 1.7 W/m2K with well-matched shutters.


The most obvious solution may seem to be replacing windows — and in some cases it makes sense. This market is saturated with PVC double-glazed windows, which, in my opinion, is not recommended. Wooden versions are widely available and will preserve the look and value of your antique property.


However, most of the advantages of such a replacement can be achieved through the use of secondary glazing, which is not only much cheaper to replace, but also has a much smaller impact on the environment.


Thanks to this technique, it is also possible to preserve the historical homogeneous cylindrical glass with all its attractive disadvantages, while improving its parameters (the heat transfer coefficient U can reach 1.8 W/m2K, and in combination with other measures it can be even better).


If early-release double-glazed windows are already installed in your house, it is unlikely that they will be as effective as double-glazed windows manufactured in accordance with current legislation. However, in most cases, the savings from switching to newer versions with double or triple glazing outweigh the costs of electricity and replacement.


Wall insulation.

There are three main classes of walls in the housing stock, and the construction time of your property can help determine which one was probably used.


The dates listed below are approximate — and you should always carefully examine the condition of your property before proceeding with repairs — but they give a decent overview:


Strong (single-leaf) wall construction - brick or stone - until 1919.

Non-insulated diaphragm walls - bricks and blocks - 1920-1975.

Membrane walls, insulated - bricks and blocks - after 1975

The walls are filled.

They can be insulated inside or outside. In any case, this is an expensive process, and the benefits should be carefully weighed, especially when the facade contains a large number of windows or doors.


The insulation of the exterior walls has the advantage that the original masonry becomes a heat accumulator capable of absorbing and radiating heat back into the living quarters – thus achieving a very effective result in terms of thermal efficiency. This method involves adding a new, weather-resistant layer to the outside of your property, so it's important to describe it carefully.


The use of sealants should be avoided, as they deteriorate over time. It is also recommended to use insulating materials that are open to moisture, such as sheep wool, since otherwise water entering the wall structure will be delayed, which will lead to dampness in the inner walls.


The key point is that for houses of the past it may be important to preserve the appearance of the original building, which may make it difficult to apply this method. However, it can be considered for use on some rear facades or on objects that were plastered later.


For comparison, the insulation of internal walls is not as effective, since it reduces the ability of the wall to accumulate useful heat. This will also slightly reduce the internal floor area, and may also affect the historical features of your home, as the original baseboards and moldings are difficult to preserve or accurately recreate. You will also need to remove and reinstall any plumbing such as radiators and electrical outlets.


This solution will lead to the fact that the initial masonry walls will become colder, which, in turn, will reduce their ability to cope with moisture ingress. Therefore, before installation, make sure that the building is weatherproof.


An independent expert will be required to assess the risk of condensation and mold formation at the boundary between insulation and brickwork, so moisture-resistant materials should always be chosen.


It should also be remembered that in places where such insulation cannot be used, cold bridges may occur (when heat escapes through a structural element that has a direct connection between the inner and outer parts). These can be places such as the abutment of stairwells to the exterior walls and suspended elements of the upper floor. In these places, condensation is most often formed.


Diaphragm walls.

Until the mid-1970s, diaphragm walls were built without insulation, since the outer layer was considered simply as protection from the weather. Currently, it is customary to modernize the walls with insulation by introducing it into a crack – a relatively cheap and simple process that does not violate the interior space.


However, in recent years there has been an increase in the number of failures of this type of diaphragm wall insulation. This is due to the fact that the gaps between the masonry slabs are designed so that they can be ventilated, and modernization prevents this.


In case of defects in the exterior coating, such as cracked plaster, water gets inside and is delayed. Water seeps into the building, causing mold to grow where it did not exist before.


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