አዲስ አበባ የሚገኝ ሕንፃ

የጅማ መንገድ ጊቤ ድልድይ

በቄራ የሚገኝ ቤት

ሁላችንም ግድግዳዎች ላይ፣ ወለሎች ላይ፣ ቤቶች ወይም መንገዶች ላይ ስንጥቆችን አይተናል፤ ብዙዎቻችን ወድያው የምናስበው በግንባታ ላይ የሆነ ችግር እንደተፈጠረ ነው። እንደ እውነቱ ከሆነ፣ አብዛኛዎቹ ስንጥቆች በጣም የተለመዱ ናቸው።

የሃይል ውጥረት

ስንጥቆች ሕንፃው ለሃይል ውጥረት፣ ለሙቀት ለውጦች፣ ለእርጥበት እና ለእርጅና እንዴት ምላሽ እንደሚሰጥ የሚያሳይበት መንገድ ናቸው።
እነዚህ ፍንጮች አንድ መዋቅር እንዴት እየሰራ፣ እያረጀ እና ለአካባቢው ምላሽ እየሰጠ እንደሆነ የሚያሳዩ ናቸው።

ከትንሹ ቤት እስከ ረጅሙ ሕንፃ ድረስ ያለው እያንዳንዱ ግንባታ ከጊዜ በኋላ ምልክቶችን ያሳያል፣ እና ስንጥቆች በጊዜ ሂደት የሚፈጠሩ ሁነቶች ናቸው። የቤት ባለቤት፣ ተከራይ ወይም ስለዚህ ጉዳይ ለማወቅ የሚፈልጉ ከሆነ፣ ይህ መመሪያ ስንጥቆች ምን እንደሚያመለክቱ፣ የትኞቹ ምንም ጉዳት እንደሌላቸው እና የትኞቹ ትኩረት እንደሚያስፈልጋቸው ለመረዳት ያግዝዎታል።

ስንጥቅ ማለት ምንድን ነው?

የፕላስቲክ ማስመሪያ ለማጠፍ ይሞክሩ። መጀመሪያ ላይ በቀላሉ ይለመጣል። ትንሽ ተጨማሪ ጉልበት ሲጨምሩ እና ማስመሪያው ጠንከር ይላል። በደንብ ጉልበት ሲጨምሩ ግን ማስመሪያ ይሰበራል። በግንባታ ቁሳቁስ ውስጥ ያለው ስንጥቅ በተመሳሳይ መንገድ ነው የሚፈጠረው፤ በቁሳቁሱ ላይ ያለው የክብደት ውጥረት ከቁሱ ጥንካሬው ሲበልጥ የሚፈጠር መከፈል ወይም ክፍተት ነው።

እንደ ኮንክሪት፣ ሸክላ ጡብ፣ እንጨት፣ ልስን እና ብረት ያሉ ቁሳቁሶች ሁሉም ክብደት የመሸከም አቅም ገደቦች አሏቸው። በእንቅስቃሴ፣ በሙቀት ለውጥ፣ ጥራት የሌለው ግንባታ ወይም በተፈጥሮ እርጅና ምክንያት - እነዚህ ገደቦች ላይ ሲደረሱ በመሰነጣጠቅ ምላሽ ይሰጣሉ።

እንደ ፕላስቲኩ ማስመሪያ ወይም ከላይ እንደሚታየው ፊኛ፣ አንድ ሕንፃ ስንጥቅ ስለታየ ብቻ አይፈርስም። ስንጥቆች የሚታዩ ፍንጮች ሆነው ያገለግላሉ፤ አንዳንዶቹ ምንም ጉዳት የሌላቸው፣ የተለመዱ ለውጦችን የሚያንፀባርቁ፣ ሌሎች ደግሞ ትኩረት የሚያስፈልጋቸውን ውጥረት ወይም እንቅስቃሴ ያመለክታሉ።

ስንጥቆች ለምን ይከሰታሉ?

ስንጥቆች ብዙውን ጊዜ የሚከሰቱት ከአንድ ምክንያት ይልቅ ከተለያዩ ምክንያቶች ጥምረት ነው። በጣም የተለመዱት ምክንያቶች እነሆ፡

• የሙቀት ለውጦች፦ Materials expand in heat and contract in cold. Over time, these tiny movements can add up and cause cracks.
  Example: Long concrete walls without expansion joints often develop straight cracks because they have nowhere to expand.
• Moisture, drying, and shrinkage: Concrete, plaster, and mortar shrink as they dry, sometimes unevenly, creating hairline cracks. Excess moisture can also weaken materials or corrode steel, leading to deeper cracks.
• Soil movement and settlement: The ground beneath a building can settle, shrink, swell, or shift, affecting floors and walls.
  Example: Clay soils swell during rainy seasons and shrink in dry ones, causing cracks in foundations or walls.
• Aging of materials: Over time, concrete becomes brittle, steel corrodes, wood warps, and paint peels. Natural aging can make cracks appear.
• Heavy loads and external forces: Vibrations, strong winds, storms, machinery, or nearby traffic can stress buildings, sometimes leading to cracks.
• Construction or design issues: Poor-quality materials, weak foundations, inadequate reinforcement, rushed construction, or lack of expansion joints can cause cracks to appear later.

Where Do Cracks Happen Most?

Cracks can appear anywhere, but some areas are more prone because they face higher stress:

Around windows and doors: Weak points where movement shows

Corners of rooms or buildings: Stress concentrates here.

Junctions of different materials: For example, brick meeting concrete.

Floors and roof slabs: Affected by shrinkage, moisture, and temperature changes.

Columns and beams: May crack from bending, shear, or corrosion.

Foundations and base of walls: Settlement often creates diagonal or tapered cracks.

In general, cracks follow the weakest path—mortar joints, thin sections, or lightly loaded areas—giving clues about how the structure responds to forces.

Shapes and Types of Cracks

The shape of a crack can provide insight into its cause and severity. Here’s a simple guide:

Understanding these patterns helps determine whether a crack is cosmetic or requires professional attention.

Are Cracks Dangerous?

Most cracks are harmless, small, and simply part of how materials age and move. However, some cracks signal deeper structural issues, especially those caused by foundation movement, heavy loads, or design flaws. Key points:

Hairline cracks are usually safe.

Larger, growing cracks—especially diagonal, stepped, or wider than a few millimeters—may indicate ongoing stress.

Active cracks that continue to widen should be inspected by a professional.

Knowing what cracks mean can prevent unnecessary worry, help you catch problems early, and ensure safer homes and buildings.

Can Cracks Be Maintained?

Cracks aren’t something we “maintain” the way we maintain paint or flooring. Instead, the goal is to prevent them, repair them, or manage them depending on their cause and severity.

• Small, stable cracks (hairline, <1 mm): are often harmless and can be left alone or sealed/repainted to stop moisture.
• Active or growing cracks: should not be filled with rigid materials (cement, hard epoxy) which may reopen or create new cracks. These types of crack need flexible sealants (mastic, polyurethane) to allow movement.
• Structural or large cracks: fix the underlying cause first (settlement, soil movement, corrosion, etc.) Then use specialized repairs like epoxy injection or stitching.

What’s Next?

In the next post, we’ll cover:

1. How to prevent cracks: Simple maintenance, proper construction practices, and habits to reduce cracking.
2. How to assess cracks safely: Tips for checking a crack’s size, location, shape, and growth without risk.
3. When to call a professional: Signs that a crack may be structural and guidance on which experts to contact.

With this knowledge, you’ll feel confident recognizing cracks, understanding their causes, and taking the right actions to protect your building.