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Today, after visiting a site where the client complained about dampness and swellings on her wall, i decided to create this post. Its supposed to be for professionals only but for the sake of humanity, i have decided to make it open to anyone out there who might need it to make a difference.
Because i am making this post on the importance of over site concrete during the rainy season, i would like to ask the following questions:
1. Have you ever walked into a building and discover there are molds or swelling just around the floor area of the building as shown below?
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| Dampness On Walls |
2. Have you ever walked into a tiled building only to discover there are some cracks or gaps between the cement used to tile the floor and the bottom part of the walls as shown below?
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| Floor almost sinking as a result of no German flooring |
Did you also notice that in some buildings, the tiles are actually losing their grip on the building, in other words, the tiles seems to be caving down or gradually losing themselves from the walls
3. Have you ever walked into a building and discover there are voids on the floor which result to a disturbing sound especially when you walk on shoes?
If your answer to any of the above questions is “Yes”, then its time we talk about the reason why you’re seeing such in your building.
Its all about German Concrete Or Over site Concrete.
What Is Over site Concrete Or German Flooring?
Over site concrete is simply that layer of mass concrete laid after filling. It is another cost effective element installed when your structure is at the DPC (Damp Prove Course). It is made with a mixture of coarse and fine aggregates and cement along with water in the right proportion (Mostly 1:3:6).
Can I Build Without Over site Concrete or German Flooring?
The answer to this question is “Yes” But a “No” would be the most honest answer here especially when your building is located in a swampy soil or a water logged piece of land.
What Is The cost Of Over site Concrete?
Over site concrete as it stands is quite expensive especially since granite, sand and cement are a must for it, but do not let the cost of it at this stage of your building cause you to run away from it. If You do it now, you’ll save yourself the future cost of repairs or amendments especially if your site is located on a swampy or waterlogged area.
Do i Need Over site Concrete Even When My Site Is Located On a firm soil?
Yes! You need it because aside from the fact that You’ve imported or are going to import foreign materials during at the filling stage, there is what we call settlement which will occur beneath the structure and in most times it happens when you do not even know.
Also, if you do not German floor your building, settlement will occur and the tiles fixed would begin to cave, then as you use water in the bathroom, water percolates into the ground from the bathroom. The water usually percolates from the tiny pores between the wall and the floor and before you know it, Voids begin to accumulate under the tiles. This is very dangerous to your walls and the stability of the entire structure.
What Are The Materials Needed For Over site Concrete Or German Flooring?
You’ll need
1. Cement (Binder)
2. Water
3. Granite (Coarse Aggregate)
4. Sharp Sand (Fine Aggregate)
5. Boulders (Crushed stone)
How Do I Calculate Amount Of Materials Required For German Flooring or over site concrete?
I will create a post on this. On This post you’ll learn how to calculate the number of bags of cement, Trips of sand and granite required for your over site concrete.
Why Are Boulders Or Large Stones Used In Over site Concrete?
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| A building Currently In Over site Concrete stage |
1. Boulders are used in order to enhance the strength of the over site concrete
2. it provides a sitting platform for the German floor itself or the over site concrete
3. The hardcore saves cost as the space occupied by stones will help reduce the amount of concrete that would have been used in the absence of the stones or boulders.
4. The gap between the over site concrete and the earth or filling material serves as capillary cut off for water. it prevents water from moving up the walls
5. It serves as a factor of safety against dampness.
What Are The Structural Importance Of Over site Concrete Or German Flooring?
Aside from preventing you from answering “Yes” when the 3 questions asked at the onstage of this post, Over site Concrete will help or enable you in the following ways:
1. It Ensures your structure stands evenly. In other words, it helps to ensures levels are equal. little wonder builders use leveling equipment or nails to ensure the level is uniform.
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| Over site Concrete Ensures the structure is of uniform level |
2. Over site Concrete or German flooring helps your structure in 2 ways.
a). when there is a crack in your block wall, the German flooring prevents this crack from extending to the foundation
b). when such cracks actually emanate from the foundation, the German flooring stops it from extending to the superstructure (The part of the building above the over site concrete)
3. In Soils where there is earth movement due to settlement, the over site concrete or German flooring helps transfer the forces to other parts of the building thereby preventing the collapse of your building
4. The Over site Concrete makes for stability of your building. it helps to distribute loads (Live and dead loads) from the beams, columns and finally to the foundation. It also serves as an absorber for earth tremors and vibrations.
5. It stops water from the bathrooms from percolating below the foundation. This means you’re actually doing your foundation more good than harm when you have a German floor or over site concrete installed.
6. If feeling was made with clay, German flooring serves as cut-off to capillary action which would enable water move up to the walls and bring about dampness in the building. Dampness ruins the beauty of the building especially paintings.
Thank you for your patience through this post. I hope you have now learnt the few importance of Oversite concrete or German flooring. I hope you now understand the reason behind some funny coloration you see on parts of the wall close to the floor.
Please share with others and keep a date with Building Contractor secrets because there are myriads of topics i am yet to treat professionally.
Thank you very much for this.. One question pls.. Is it necessary to use wire mesh for reinforcement in German floors? Or are there conditions that it will needed ?
Well, wire mesh is highly recommended for German floors but it depends on the pocket of the client and the purpose of the structure.
Using a wire mesh saves you future cost and also ensures the floor is firm enough to carry loads without failing.
I'll talk about this in my other article
Hello sir. Thanks for the wonderful information contained here. Please my question is, how long does one allow the german foundation to dry before starting construction work on it.?
Take 10 days my dear, but I must warm you…
Curing us a must
Curing would ensure the setting and hardening is uniform.
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Can you do German flooring after blocks have been raised up to lintel level.
Thanks for well detailed article on German flooring. Just curious, what if the foundation is done, blocks have been raised to lintel level, can one go back to do the German flooring?
You can but be ready to face the consequences as highlighted above by the writer
Educative read ✔️
Thanks for stopping by sir
If one uses boulders,is it necessary for wire mesh?
I thought the boulders is an alternative to wire mesh.
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Wire mesh is not really compulsory. The engineer will decide depending on the condition of the site