Parapets Capping and Windows Sill

Parapet is an extension of wall at top roof, balcony, stairs or a walkway, used as a guard rails. As the parapet function is guard rails, then it hasn’t been less than 80 cm. or it has to install handrail over it. Parapet is covered with capping to protect plaster, stone cladding, curtain wall or any other wall finishing material from water leaking. For same reason windows sill is used for the bottom side. The windows sill and parapets capping could make in different details and from different materials. This post will discuss capping and sill materials, details and recommendations for well installation.

Parapet capping for flower box, made of Palestinian marble, Gaza 2020
Parapet capping for flower box, made of Palestinian marble, Gaza 2020

Design Details

There are several design details for parapet capping and windows sills. There are different designs however they all have the same functions. Here we will introduce some of the parapets capping and windows sill design details.

sill and capping types : straight, round edge, double edge, round double edge, By Zahi Alrayyes 2020
sill and capping types : straight, round edge, double edge, round double edge, By Zahi Alrayyes 2020

Straight: simple but need to chamfer the corners to make the sharp edges safe.
Round edge: for better appearance and for classical style use a round edge capping and sills.
Double: for larger scale use double marble pieces to have thicker sill. This suite residential and commercial modern buildings.
Double round edge: for lavishness or large scale, use double round edges, it has extra cost than previous choices. Typically used for villas and high quality residential buildings.

Double marble emperador meduim sill
Double marble emperador meduim sill, Gaza Alhelou Station 2018

How to Select the Capping and Sill Materials 

Parapet capping and sill material has to have a low water absorption ratio and to resist weathering. So marble, granite, aluminum and concrete are suitable materials to use. 

Marble is a suitable material for parapets capping and windows sill. Select marble with low water absorbing ratio, also order pieces with more length to have fewer connections between marbles, usually it cut into 150 cm length. The connection will be filled with cement or marble adhesive. Marble is cheap, easy to install and to decorate. Marble effecting from weathering, marble veins and pores will enlarge. Tiny veins will allow water to enter through the marble sill and capping. This problem fixed by either filling the pores and veins by cement or marble adhesive.

Marble capping has defect veins and pores from weathering that accrue water leaking, Gaza 2020
Marble capping has defect veins and pores from weathering that accrue water leaking, Gaza 2020

Granite has low water absorption ratio and can resist weathering more than marble. But usually granite colors are dark and light colors have a high price. Also granite doesn’t have many pores that’s perfect with water absorption but cement mortar won’t bond well it. Therefore there are some chemical products we use for granite backside in order to make it rough for better bonding with mortar. This problem appears more after installing fixtures over the granite sill and capping, like handrail. Where opening a hole in granite after installation or even screws will shake the sill and disassemble it from cement mortar. Therefore we recommend to open holes in a method that won’t shake the sill and capping like, water jet.

Double round edge from Rosa Betta marble, Gaza 2020
Double round edge from Rosa Betta marble, Gaza 2020

Mosaic and terrazzo is a white cement material that cast in place. This will give more bonding to the parapet capping and sills. In my view point it looks nice when it has a light large stones like Perlato size 5. Mosaic and terrazzo is cheap comparing to marble and granite. Also it fit stairs and curved parapet. Long length sills requires expansion joint, it’s made from glass as shown in the following photo.

handrail parapet capping from mosaic, by Almamoura Company, Gaza 2020
handrail parapet capping from mosaic, by Almamoura Company, Gaza 2020

Installing Parapets Capping and Windows Sill Recommendations:

  • Install parapets capping and windows sill after the block works, and stone wall cladding and before plastering works. Paint the sills with lime and sand to avoid cement stick to marble during plaster and painting works.
  • Sill size, for width leave a cm or two for plaster works thickness, and leave 3 cm for tiles works. For the outside, leave two more centimeters to have a cantilevered sill. The cantilevered sill will allow water to slide away from the walls to prevent water dripping the wall. Also prevent water dripping by a grove in the bottom surface of the sill or capping. 
  • The capping or sill length has to be straight leveled. For the width make few millimeters slope toward the outside to allow water slide outside instead of leaking.
  • For corners use 45 or diagonal connections, they look nice and will bond together better than any other connection.
Parapets capping corner connections, Gaza 2020
Parapets capping corner connections, Gaza 2020

FAQs

What capping to use for curtain walls?

For curtain walls and aluminum composite panels  facade use aluminum capping. Aluminum capping can be done by a certain profile or customized from ACP. Remember capping and sill function is to prevent water leaking and the material has to prevent weathering, then aluminum is perfect.

Concrete Floor Renovation – Concrete Grinding

Grinding Concrete surface
Grinding Concrete surface

Concrete floors are elegant, especially when it’s smooth and colored. Concrete is hard to maintain, many factors can affect the quality of concrete. In an average of 20 years concrete top surface will begin to crack and fragment. Maintenance of concrete surface is hard mission, where it could paint using epoxy layer. However epoxy look nice, it does not suit outdoor applications because the sun will ruin it. Therefore it will not last for long period and will be expensive solution. On the other hand, grinding concrete top surface is another solution, however it grinds is a hard and sensitive mission. This topic will discuss the process of concrete grinding as FAQs. I got these informations throughout my experience at renovation of a petrol station that has a concrete floor.

FAQs

By grinding the surface it will remove the color?

The concrete color is a powder added to concrete surface during concrete initial sitting. Craftsman distributing color powder by throwing it over the surface. Thickness of colored layer can’t be customized, and it isn’t equal it all areas. Therefore, if concrete defected and cracks are small then it will be easier to grind a thin layer and keep it color. In case of large cracks it has to be grinding until reach concrete gray color. Noted that color layer thickness usually is few millimeters, but could be a few centimeters in some spots. 
Remove concrete floor color

What are the machines used for grinding concrete?

Grinding concrete is about the blades, the blades can install at hand grinder or floor grinder machine. Floor grinder is better because it gives level grinding surface, however floor grinder is hard to reach small area. Hand grinder is suitable for small areas, but it requires a skill worker to smooth and level concrete surface.
Concrete grinding blades came in different sizes, 10” to suite floor grinder and 7”, 5” and 4” fit hand grinding. When blade’s segments number increases it will grind faster, also different segments shapes can give smoothing, leveling or reaching corners. Producers write at the products the differences between them and where to use each.
Concrete grinding machines

How to collect dust during grinding?

Grinding the concrete surface will cause a lot of dust, dust is air pollution that affect the environment. Also the powder on the surface has to be collecting because it will give roughness to the surface. Dust can collect by a vacuum (dry grinding) or by pouring water (Wet grinding) to dissolve the concrete power in order to remove it away from site.
Dust during grinding concrete

What is the difference between wet and dry grinding?

Wet and dry grinding are methods to collect grinding dust. Dry grinding is to collect dust by vacuum, where it requires a special system and accessories for tools. Wet grinding requires fewer machines and installation, it requires water only. However wet grinding requires less installation, water will ruin the blade faster.Also powder and water will contaminate the sewage system, especially when it has a colored powder.

Grinding Concrete will result smooth surface?

Unfortunately, concrete has sand therefore it will not be smooth as top surface or terrazzo tiles. Sand particles are very strong and hard to break, sand used for sanding materials to have rough surfaces. So sorry you will not have a smooth surface.

How can i get a smoother concrete surface?

By adding chemical materials like stains. Stains will make concrete appear as it’s wet, although different products have different glossiness. Stains also protect the concrete surfaces from scratching and reduces absorption to avoid oil and water leakage inside the concrete.
Concrete sealer

Can i paint the grinding surface?

There are anti-scratch paint types, also use outdoor paints to protect it from the sun rays. Some types of epoxy paints has auto level specifications, which will level the surface in order to have it smooth and elegant. Some types of stains have color in it, it will remain translucent and concrete texture will appear in different colors. 

How can i add aluminum profiles to concrete?

This by creating a saw cut in concrete surface in width of few millimeters and few centimeters deep. Then using Sikaflex product to glue aluminum T profile to the groove on concrete surface. Be careful to clean aluminum and the groove from any dust before glue it. Remember that aluminum is installed at the floor, and it’s prone to scratching and unglued from concrete due to movement.

History of Building Materials

A Timeline study about building materials, this study was presented in Lighthouse center of design in Glasgow – Scotland. The study was a part of architect Charles Rennie Mackintosh exhibition who designed the Lighthouse center.

History of building materials
History of building materials, by Z. Alrayyes 2011

History of Building Materials

Ages before, vernacular architecture in all around the world depended on building materials from earth and surrounding areas. For instance In Palestine using limestone and clay bricks, In London using bricks and Portland stones. Also In northern countries using pine wood to build ,In north pole using ice as building materials. Throughout another climate like Arab gulf woven animal hair to build tents, In Algeria they were digging and carving underground houses. Hassan Fathi the Egyptian architect who have the concepts to create buildings from what earth have, ending up with a great architecture appearance and concepts. Architecture in each area of the world had it own character, building materials was one of the affecting factors beside ideology and climate …etc.

Architecture from Geology

In architecture and civil engineering building materials classify according to tension and compression strengths. If tension strength is higher than compression strength it called strength materials and visa versa. Bamboo and steel are tension materials where it resists high tension forces while it bends at a little compression forces. On the other hand, stones and bricks are compression materials, also a little tension force can ruin the material structure. These specifications of materials require certain rules to resist forces, in order to create architecture. These rules call engineering, building codes contain formulas, rules and methods of construction of different materials. When forming and engineering  materials to buildings, it will give a different result at each area, climate and users social behaviors. These differences in architecture have a special beauty, where people travel the world to see different architecture and culture.

Building Materials in Modern Architecture

After the industrial revolution and appearance of engines and shipping ships. Building materials can easily transport from one country to another. Nowadays markets are full of imported building materials. People in the Middle-East use the same materials people use in Switzerland. This means that architecture in China is similar to Middle Africa and Russia for instance. Wondering how people after several decades will look at our architecture.

FAQs

Does the development of building material effect the structural system?

Yes, most of historical building materials like clay, stone are compression materials. This means it could resist compression forces, also some materials like stone may resist tension forces. Compression materials could resist tension forces in smaller amount than compression forces, this why its called compression materials. Compression building materials allow building using bearing walls structural system, where it can’t build straight roofing. Bearing wall depend on walls, arches, vaults and domes to transmit loads forming a space. Aya Sophia is a good example of bearing wall structural system. On the other hand, the development of building materials like concrete with reinforcement steel bar – tension material – we can build straight roof, multi-story buildings and a larger spans. Tension building material suite the skeleton structural system that most of the world building using it.

Methods of ceiling marble cladding

Marble ceiling cladding gives the architecture feeling of marble masses, the building appear as a piece of marble. However there are several types to install marble at ceilings, each method has advantages and disadvantages. Through this article we will discuss ceiling cladding methods,then you can make a decision about which method to use.

There are three methods of installing marble at ceilings. A method before casting the slab and two methods after casting the slab, one of them is using mechanical system. We will discuss the mechanical way of installing in another topic.

Before casting slab method

it’s the most common and simplest way of installing. Where marble place on the wooden framework, and it installs a steel inside the marble. Marble adhesive used to connect marble tiles together. This method sounds easy but it doesn’t reach a good result because it may move during concrete casting. Tiles could move, then it is recommended to put a mortar over the marble to enhance the bond and to protect marble adhesive from ruin by sun rays.

A problem facing this method, frameworks surface is hard to get it leveled, and any defect will appear clearly. Solving this problem can be either by chamfer the tiles edges, then it’s hard to notice its not level. Another alternative is to adopt the wood frame level, either by putting an over layer plywood to re-level the surface. For professional it’s recommended to make cladding surface lower than the rest of the slab by 5 cm. Then put sand into this area and arrange marble tiles as its verse tiling, then you can control the level precisely. 

marble cladding for ceilings methods
During working at marble cladding for ceiling, and before installing it rips blocks and steel bars. Gaza 2018
This craftsman, install Travertine tiles for ceiling cladding, using before casting method. He uses small marble pieces to gather tiles at same level by marble adhesive. Gaza, ORIGIN DESIGN, 2019
marble cladding for ceilings defects
marble cladding for ceilings defects, Gaza 2018

After casting slab – by casting method

This method has a better quality than the previous method, but it is not suitable for a large area. By making a new framework underneath the slab and by leaving the thickness of the marble and a space for cement mortar. Then steel wire will connect to the marble tile, after that arrange marble at the framework. Then connecting the marble wires to a steel mesh connecting to the concrete slab, and then it’s ready for concrete casting. We need to cast the concrete from the top, this by opening a 10 cm open at the concrete slab. But be aware to add more water to the concrete and extra cement to have a good concrete suitable for this job. It’s better to open several openings for casting at the slab. Because we need concrete to reach the top and air will get out through them.

After Casting method, Gaza 2018

As much as marble has a brilliant appearance at ceiling but also installing it is not an easy job, and it’s hard to fix and defects after installing. 

How to fix marble ceiling cladding defects?

Usually for before casting methods, and some installation defects appear after removing the slab frameworks. Some tiles aren’t at the same level, this time we tried to solve this by doing a groove between the tiles. A three grooves along the balcony solved much of the problem. Here are photos from before and after for solving the problem. 

Marble cladding for ceiling that has some defects, where tiles aren't at the same levelMarble cladding for ceiling that has some defects, where tiles aren't at the same level, solved by doing groves between tiles