How to prevent dampness in a building

How to prevent dampness in a building

Dampness in a building may occur due to faulty construction, the use of poor-quality building materials or bad architectural design. Dampness affects the lifespan of a building or structure, but it also creates unhygienic conditions. Mold and fungi love to grow in damp conditions, so it is best to fix any signs of wet concrete as soon as possible.

The measures taken to prevent water from leaking into a roof is usually called waterproofing. The treatment given to a structure to keep its basement, floor and walls dry is called damp proofing. Some of the problems caused by dampness in a building include the disintegration of bricks, stones, tiles; the softening and crumbling of plaster; the corrosion of metals; the warping, buckling and rotting of timber; the presence of termites; deterioration to electrical fittings and the bleaching and flaking of paint with the formation of coloured patches.

What causes dampness in a building?

The absorption of moisture by building materials is one of the main causes of dampness. This can be caused by faulty structure design, bad workmanship or the use of defective structures or materials.

Sources of dampness in buildings include the rising of moisture through the foundation walling; splashing rainwater which rebounds after hitting the wall surface; penetration of rainwater through unprotected tops of walls, parapets or compound walls; gutters which allow rainwater to descend through the top supporting wall. In the case of buildings with flat roofs, inadequate roof slopes, improper rainwater pipe connections and defective junctions between roof slabs and parapet walls can also cause dampness.

How to prevent dampness in a building

1. Membrane Damp Proofing

This involves placing layers of water-repellant materials between the source of dampness and the structure. This type of material is commonly known as damp proof course (DPC). It could be made from materials like plastic or polythene sheets, cement-based concrete, bituminous felts or asphalt. Applying DPC in a basement is usually referred to as tanking and can prevent ground moisture from seeping into the concrete walls.

2. Integral Damp Proofing

This form of damp proofing involves adding certain waterproofing compounds to the concrete mix to increase its impermeability (resistance to absorbing moisture). The compounds made from sand, clay or lime help to fill the voids in concrete and make it waterproof. Compounds such as aluminium sulfate, calcium chlorides and alkaline silicates chemically react when mixed with concrete, producing waterproof concrete.

3. Surface Treatment

This type of treatment involves filling up the pores of the surfaces subjected to dampness. Water repellent metallic soaps such as calcium and aluminium oleates and stearates are often used for this purpose. Cement coating, transparent coatings, paints, varnishes and bituminous solutions also fall under this category. Another economical option for damp surface treatment is lime cement plaster. This effectively prevents dampness in walls as a result of rain.

4. Guniting

For this type of damp-proofing, a cement gun machine is used to deposit a layer of rich cement mortar over the surface. The surface must be completely cleaned of dirt, dust, grease or loose particles by wetting it properly. Cement and sand (or fine aggregates) are then fed into the machine. This mixture is finally shot onto the prepared surface under a pressure of 2 to 3 kg per square centimetre by holding the nozzle of the cement gun at a distance of 75 to 90 cm from the working surface.

5. Cavity Wall Construction

This form of damp-proofing consists of protecting the main wall of a building by an outer wall, leaving a cavity between the two walls. The cavity prevents moisture from spreading from the outer to the inner wall.

These five methods of damp-proofing will help to protect concrete structures from excess moisture, which can lead to mold, fungus, rot and damage to buildings. Contractors and homeowners must always inspect their buildings for any signs of stress and damage, such as dampness, which could affect the integrity and durability of the structure.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

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LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

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At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

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Ideal building orientation in hot and dry climates

Ideal building orientation in hot and dry climates

Buildings should all face certain directions, depending on their location in the world – in the Southern Hemisphere, they should ideally face north. The reason for this is to provide residents with comfortable living conditions throughout the year. This is done by optimising on the sun’s warmth during winter, which shines from a more northern point in the sky.

In hot and dry climates, which generally occur at latitudes between 0 and 30 degrees, the daytime temperatures in summer can peak above 45 degrees Celsius. Tanzania falls within these latitudes, but is located just south of the equator. These climates do not receive excessive rainfall during the year and the humidity can be quite low.

The buildings in these climatic zones should be orientated so that they receive as much sunlight in winter and as little sunlight in summer as possible. The ideal orientation is north-facing. This means that the main windows should face in a northerly direction in order to allow light and warmth into the house during the cold of the winter. 

In summer, the sun is further south. This means that no sunlight will enter the main windows and doors, keeping the building cooler during the heat of the day. The building orientation depends on the architect and building contractors, but it can have a big impact on the internal temperatures of the rooms, throughout the year.

Typical features of buildings in hot and dry climates

1. Building layout – Different rooms should occupy different positions in a house. Long walls with windows should face north to maximise solar exposure during winter. The kitchen should be placed on the downwind, or leeward, side of a house. This will prevent hot air and the smell from the kitchen blowing through the house. Bedrooms can be located centrally to keep them insulated from outside temperatures.

2. Windows and openings in the walls – Large windows and openings in the walls should face north and west. This will allow the warmth from the sun to enter a building in winter and at sunset. During summer, the sun won’t shine through north-facing windows, but it will still shine through west-facing windows at the end of the day, providing a bit of warmth for the night. 

3. Layout and building of walls – The thickness of the wall plays a big role in heat insulation. Buildings in hot and dry climates should have thick outer walls to act as an insulating barrier, keeping the house cool in summer and warm in winter. Houses should be painted light colours in hot climates to reflect the sun’s heat. The paint should also be smooth and glossy to further insulate the building.

4. Layout of the roof – The roof of a house in a hot climate should be well-insulated and slope in a windward direction. This will allow the roof to cool as the wind blows directly over it. The insulation will also stop the heat from the roof entering the house during hot summers. Ideally, roofs should be tiled with concrete or clay tiling, not tin. Tin roofs can get extremely hot during summer, whereas concrete is a better heat reflector and insulator; concrete tiles will keep a house cooler in the summer and warmer in the winter.

5. Vegetation around a house – The trees and bushes around a house play a big part in its thermal properties. Large trees cast shade over windows, walls and roofs. These should be planted on the south side of the house to provide maximum shade during summer. Make sure that the roots do not grow into the building’s foundations.

In hot and dry climates, such as Tanzania, building orientation is important. It determines how warm a home can be in winter and how cool it can stay in summer. Architects and contractors should pay attention to the orientation of a building when designing and constructing it.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

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Different ways to use recycled concrete at home

Different ways to use recycled concrete at home

In the construction industry, large quantities of waste material are often generated through the course of the project. Did you know that a lot of this material could be repurposed or recycled? It is ideal for projects around the home and the garden and it also prevents waste from ending up in landfills.

Concrete is a material that is ideal for recycling – it is 100% recyclable. At construction sites, recycled concrete is often available for free – some contractors will even deliver the concrete to your house. Concrete is inexpensive and durable and can be repurposed in various ways. Here are some examples of uses for recycled concrete:

Raising garden beds above ground

There are many benefits to raising a garden bed a few inches above the surrounding soil. It improves the soil drainage and also helps to warm soil so that seeds germinate quicker in spring. Raising garden beds 30 to 50 centimetres high will make it easier for people with limited mobility (like older people or physically challenged individuals) to do gardening.

Walkways and garden paths

Build new paths and walkways around your home and yard by using concrete paving stones or pieces of rubble. Try to get rubble from a single demolition site for your project. This will make it easier to find pieces of the same thickness, which makes it easier to handle and work with. Keep in mind that walkways built from separate pieces of recycled concrete (from various demolition sites) will have many gaps for rainwater to soak into the ground.

Aggregate and drainage

Sometimes a project requires small pieces of aggregate – materials used for mixing with cement, bitumen, lime, gypsum or other adhesive to form concrete. Many municipalities have companies that recycle old concrete into small pieces of aggregate. This aggregate is inexpensive and very useful for poured-concrete projects. 

These small particles of aggregate also make good drainage materials. You can use it as an alternative to gravel in wet areas. For example, you can dig a trench through an area where water collects. Then fill this area with concrete aggregate that surrounds a perforated PVC drainage pipe. Cover the pipe with more concrete and place the soil back.

Garden terraces and retaining walls

You can use the same technique on sloping hills to build retaining walls to prevent erosion. You can also create a terraced garden with planting sites this way. In each area where you want to build a piece of wall, dig and level a space as wide and deep as you wish to plant.

To add stability, place a layer of broken-up concrete or gravel at the base. Then stack the layers of recycled concrete. Add soil between the layers to fill in any uneven spots. When you are finished, add soil to the retaining area where you wish to plant.

Concrete is a sustainable building material. It is completely recyclable and can be used in many ways in home construction projects. Consider these uses for old concrete in your home and take advantage of a cost-effective building material.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

How to fix foundation damage on your home

Foundation damage crack in concrete

Foundation damage to any building can occur in a number of ways, from weak soil to water damage. A concrete foundation can be a difficult structure to repair, so it’s best to look after your foundations and maintain them regularly. Keep an eye out for any signs of damage and fix them as soon as possible.

It is possible to repair foundation damage without having to demolish the building, but the process can be time-consuming and sometimes expensive. Foundations are the main support structure of a building. As such, they are an integral part of a building, acting like the skeleton upon which the rest of the structure is built.

Causes of foundation damage

Concrete foundations are strong and durable. However, other problems can occur that affect the strength of these structures. Most of the time, the type of soil and moisture in the ground are the cause of foundation damage. If the soil is saturated with water, it can move beneath the foundations or cause moisture damage to the concrete.

A building can be at risk of foundation damage if:

  • It is built on clay or sandy soil. 
  • If the soil around the foundations has inadequate drainage.
  • The region experiences extreme seasonal changes.
  • There is a major plumbing or water leak underneath the building.
  • Tree roots are growing too close to the foundations.
  • A flood, drought or earthquake affects the soil around the structure.

These problems cause the soil around the foundations to move. This movement is then directly transferred to the foundations themselves, which can cause cracks to form. This can cause the building to weaken and will affect its resale value. The longer foundation damage is left, the worse the resulting problems will become.

Signs of foundation damage

How can you tell if a building has foundation damage, especially if the foundations are below ground? These are the most common signs of stress and damage:

  • Walls leaning, rotating or cracking.
  • Separation of concrete around doors, windows and corners of walls.
  • Extended cracks up the side of the building.
  • Displaced mouldings.
  • Cracking and chipping of concrete where the building meets the ground.
  • Cracks along the floor of the building.
  • Uneven floors and misaligned internal features (like doors that won’t close).

The most common sign of foundation damage is the appearance of cracks on the interior or exterior of the building. Horizontal cracks or jagged cracks along brickwork are the most serious indication of foundation damage and should be addressed immediately.

Methods to repair concrete foundations

The most ideal repair methods are those that don’t require occupants to vacate the building or move their belongings. Luckily, with modern building techniques and technology, there are a few ways in which foundations can be fixed without causing disruption to home life or business.

The two most common solutions are slabjacking and hydraulic jacking. In a slabjacking repair, grout is pumped beneath the foundations to produce a lifting force that restores the foundations to their original elevation. In a hydraulic jacking repair, steel posts are driven into the unstable ground and hydraulic jacks are used to stabilise the concrete foundations.

These methods of repair are used to fix different types of foundation damage. Before deciding on a repair method, you will need to determine what is causing the foundation stress. Get a contractor to look at the cracks and correctly determine the best repair method to use. Slabjacking is suitable for smaller repair jobs whereas hydraulic jacking may be required for bigger problems, where the soil is fundamentally compromised.

Remember to inspect your foundations regularly to catch any issues early on. Regular maintenance will also avoid further problems caused by shifting soil, excess water in the ground and tree roots moving concrete foundations. Always fix any cracks as they appear and contact a professional contractor if you believe that your foundations are compromised.

___

LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

How to make concrete floors

Large warehouse with concrete floors

Concrete floors are durable and easy to maintain. They are a popular choice in modern homes as they keep costs down and are easy to clean. The affordability of concrete floors and the fact that you can make them yourself mean they are suited to Tanzanian homes.

Items needed to make concrete floors

Steps to make your own concrete floors

  1. Using the string and the chalk, mark the desired floor height on the walls around the room. This will be your fill line.
  2. Pour a layer of crushed stone on the floor, about 2cm lower than the fill line. Using the tamper or a steel plate, stamp the stones down to compact them. Make sure they are level.
  3. Pour a layer of sand over the crushed stones and pat it flat with a trowel or shovel. The sand should be about 1cm below the fill line.
  4. Lay a plastic sheet on top of the sand and tape the edges to the side of the wall along the fill line.
  5. Mix your Tembo cement with water in a wheelbarrow. FastaPlus works best as it is durable and can support weight. Follow the instructions on the bag.
  6. Starting at the wall furthest from the door, place a layer of concrete on the plastic sheet with a shovel.
  7. Use a straight plank to scrape and level the concrete along the fill line, covering the plastic sheet and smoothing the concrete along the base of the walls.
  8. Use a trowel and extra concrete to fill in any gaps or indentations. Use a plastering trowel or a float to smooth the concrete floor nicely.
  9. Allow the concrete to cure for seven days, keeping it damp the entire time.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges.

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in the Mbeya Region at Songwe in Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

Use leftover concrete to build stepping stones

Concrete stepping stones in a grass garden

Some construction projects will leave you with a bit of extra concrete left over. Instead of throwing this concrete away, you can use it to make a variety of other concrete products, such as stepping stones or concrete blocks.

Stepping stones are probably the easiest to make and the least labour-intensive concrete product. All you’ll need is some square forms made from plastic or wood. Here are some tips on making your own stepping stones from leftover concrete.

  1. Buy some plastic forms or make your own from scrap timber. The shape is up to you; they can be square, rectangular or triangular. For circular stepping stones, you could cut a ring out of an old bucket and use that as the concrete form.
  2. Place the complete form on a plastic sheet or directly on the ground where you want the stepping stone to be. If you place it on the ground, dig a small hole in the shape of the form and remove any grass roots or leaves. Your concrete forms will fit into the hole nicely and be flush with the ground surface.
  3. Fill the form to the top with leftover concrete and allow it to cure for a day or two. If you want a textured surface to the stepping stone, you can place gravel on the top of the wet concrete, or brush the semi-dry concrete with a thick-bristle broom. This will provide grip in the rain.

Stepping stones are just one of the many things you can make with leftover concrete. You could also make a variety of other concrete products at home.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges.

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo brand of cement for over 30 years. Our head office and fully-integrated plant are located in the Mbeya Region in Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.