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The purchase and repair of an old house is done for investment purposes or most often for personal use. There is a tendency for future owners to make their choice for a new home solely on the basis of location and prices per square meter. Followed by the fastest cosmetic repair and application. However, there are many cases in which the initial budget is seriously burdened by subsequent structural defects of the new acquisition. Regardless of the future intentions of the buyer, the condition of the building is decisive for the price he should pay for its purchase. Some of the defects in the old houses are visible and can be easily noticed. Sometimes, however, they are cleverly disguised by the seller in order to increase the sale price of the property. In other cases, defects and damages can only be detected by a well-known specialist. In the following lines we will focus on the most common problems when buying an old house and their role in making the final investment decision.

Condition and coverage of the roof structure

Given the average price for repair (about BGN 20 / sq.m.) Or replacement of the roof structure (BGN 90-140 / sq.m.), It is mandatory to pay special attention to the condition of the roof. Traces of leaks and rotten wood indicate considerable additional costs that you should anticipate after buying the property.


It is not uncommon for longer leaks in the roof to affect the floor structure of the lower floors. Sellers often hide these "details" with an old rug or linoleum just below the leak.

Load-bearing structure of the building

According to statistics from the National Statistical Institute, 1447,012 buildings in the country have a masonry / brick supporting structure. About 90% of them are on one or two floors. What should we look for when choosing a house or a larger building with masonry load-bearing walls?

Avoid buying buildings with a "Prussian vault" ceiling or the presence of "short" columns

Analyzes of past earthquakes unequivocally show one thing - the mentioned elements make the building especially sensitive to earthquakes. Sometimes the presence of only one of these elements can weaken the structure at times.

Avoid buying a building with storey wooden beams

Houses with mezzanine levels from wooden joists they also pose earthquake hazards, especially when they are on more than two floors, with high ceilings and large rooms. The choice of the right system for strengthening and the preparation of a constructively sustainable project can be performed only by an expert-designer in the field. The preparation of a price offer can be done after inspection. In some cases, in order to prepare an adequate offer, a preliminary inspection of structural elements is required. The aim is to ensure the co-operation between the old structure and the reinforcement system.


Visible defects in the construction

The main causes of defects in old houses are related to:

  • reduction in time of the qualities of the bearing materialsDue to long cycles of freezing-thawing, chemical agents, direct sunlight, wetting by atmospheric or capillary waters, the bearing capacity of building materials decreases. In masonry structures this effect is expressed in the surface collapse of bricks and mortar;

  • overload of individual elements
    This condition of the vertical columns or walls can be easily assumed in the presence of "displacement" of pieces of masonry;
  • uneven subsidence of the foundationsCause oblique and vertical one-way cracks. In addition to the visual shortcomings, this process generates great additional effort in the load-bearing elements. Leads to damage to the integrity of the building and risk of accident. When the foundations settle, repairs are expensive and often unprofitable;

  • high humidity
    Високата влажност може да се появи навсякъде, като най-често можем да я срещнем в подземните помещения на къщата. Тя е съпроводена от нарушен външен вид на засегнатите от влагата места, развитие на нездравословни мухълът и плесен. В краткосрочен план може да се посочи намалената носимоспособност на зидарията при наличие на висока влажност.  Дългосрочните конструктивни последици от влагата са прогресивната корозия и намаляване носещата способност и на метални и неметални строителни материали във времето;

visoka vlaga maze

  • floods;

The most affected houses by floods are those with lime or clay mortar between the bricks. Brick and pressed bricks also suffer significant damage even with short-term wetting. The wooden elements in the joists and walls could also be significantly affected. Buying a house in an area affected by past floods is a risky decision. Preliminary consultation with a construction specialist is desirable.

  • earthquake impacts
    Structures affected by earthquakes have characteristic slopes, two-way cracks, most often on the vertical elements.

 Ремонтните дейности за отстраняването им са с висока стойност и понякога може да се окажат нерентабилни. Именно това се оказва и причината за продажба на не малък брой стари къщи. За съжаление, преди продажбата собствениците често  умишлено прикриват пукнатините в засегнатите участъци.

Quality of construction

Statistics of the causes that led to defects, damages and accidents of building structures for the period 1966-2013, shows as the main cause of implementation errors.

On initial inspection of an old house can be considered a serious drawback:

  • insufficient vibration of the concrete mixture during pouring;

  • insufficient coverage of the reinforcement;

  • stratification of the concrete mixture;

  • "Entry" of solid bricks into the column;

In some cases, these deficiencies are correctable, other times not. In any case, the cost of their repair by the new owners should not be overlooked.

"Permissible" but undesirable defects can be mentioned the lack of a vertical joint between the bricks and theirs heterogeneity by color, indicating low quality of the bricks.

Construction of a wing

The construction of a wing allows the development of a higher building density. However, in the case of individual buildings of more than three storeys, mandatory structural requirements must be observed to ensure their safety in the event of an earthquake.

The main thing to pay attention to is that the distance between the walls of the wing should be at least 7-10cm and to be missing discrepancies in height of the floor slabs. Roughly speaking, the different natural oscillation frequency of buildings during an earthquake could lead to impacts between them. The effect of such an interaction affects their vertical elements and is highly destructive.

Globally, new standards for the design, reinforcement and conservation of masonry structures continue to be developed and introduced. Constant technological progress in this area enables owners to extend the life of their building and at the same time increase its operational security. Gradually, these trends are entering our construction practice, reducing the cost of repairs without sacrificing quality.

You can contact us for assistance in choosing a new, safer home. Making the right, informed decision when buying saves big costs for owners in the future.

Do not hesitate to contact us!  

Author: Dr. Eng. Teodor Todorov