Construction guide Field Series Episode 3 Basement

Construction guide Field Series Episode 3 Basement

Basement

Construction Field series Episode 3 – R.C.C Basement bed

In this episode our technical staff will explain proceedings after following steps discussed in last episode:

-Marking for excavation
-Excavation
-Compaction
-Basement Bed P.C.C (Plain cement concrete)
-Termite Proofing

Step 7  to be discussed: R.C.C Basement bed which will include brief tutorials about:

-Toe wall for holding R.C.C bed concrete

It is a temporary wall which is made by using bricks or concrete blocks for holding the concrete of R.C.C bed, other than bricks, shuttering material such as steel plates, wood planks and palai sheets can also be used to hold concrete together.

-Vapour barrier for seepage protection

This step is carried out after making P.C.C bed and above discussed toe wall. As the name suggests, it serves the purpose of protecting basement from seepage especially in areas where water level is very close to ground. Most reliable method for vapour barrier is using PVC membrane sheets, however due to higher cost, alternate and economical method has been discussed in this video in which bitumen and polythene sheet is used as vapour barriers.

-Reinforcement 

Reinforcement is carried out as per structural drawings for basement R.C.C bed provided by the structural engineer. There should be no compromise in reinforcement of R.C.C bed as it has to hold the weight of whole retaining walls.

-Water stopper PVC for joint protection

PVC water stoppers are placed at joint of R.C.C bed and R.C.C retaining walls. It is mostly available in width of 9 inches and is placed such that it suppresses half (4.5 inches) inside R.C.C bed during pouring and remaining half in R.C.C retaining walls, hence making a barrier and joint protection.

-Concrete pouring 1:2:4 M15

M15 concrete pouring is composed of 1 ratio of cement to 2 ratio of sand to 4 ratio of crush aggregate and mixed with 24 to 25 litres water. Bed concrete should always be vibrated using a vibrator so that the mixture blends together. Better blending means more strength. After concrete pouring, it should be cured for at least 10 days to gain comprehensive strength.

RCC(Reinforced cement concrete) structure have a higher cost, and basements are constructed in RCC structures. Financially it is out of budget for most of us to afford basements. However it has many benefits e.g. extra living space, controlled temperatures in summers and winters both, safe from outside pollutions such as noise and dust etc. Basements can be designed for complete and partial accommodations. A complete accommodation includes master bedrooms with washrooms along with other divisions such as living area, store, servant room etc., whereas partial accommodation only includes later divisions. Partial accommodations are recommended more since it does not have wet areas such as washrooms & kitchens hence not requiring installation and maintenance of septic/liquid waste disposal systems.

Introduction:

Field series Episode 3

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About The Author

Mohsin Munir
Holding a degree in BS EE (Electrical engineering) and astounding knowledge of house construction business since 2010, wide experience and relevant expertise in the construction business. Believe in research based strategy while holding a distinguished position in the construction market. Started at a small scale in 2010 and recognised among the top builders and contractors in Pakistan now, especially among the expatriates and overseas Pakistanis who always trusted in our commitment and services.

13 Comments

  • Kap on October 6, 2019

    Mohsin, if i go for 1700 sft ground floor area and 500 sft basement area, then will only the 500sft basement area have concrete foundation and external walls and the rest of the foundation of ground floor will be normal brick foundation? How will this affect the per sft rate of grey structure of whole building?

    • Mohsin Munir on October 7, 2019

      Yes only 500 sqft basement area will be concrete rest will be normal brick foundations. This should not have any affect on your per sqft rate of grey structure of whole building as in standard practice labour rates for basements & upper floors are decided separately and all such aspects are taken into consideration while deciding the rate.

  • Kappa on October 6, 2019

    Mohsin, if i go for 1700 sft ground floor area and 500 sft basement area, then will only the 500sft basement area have concrete foundation and external walls and the rest of the foundation of ground floor will be normal brick foundation? How will this affect the per sft rate of grey structure of whole building?

  • Kappa on October 6, 2019

    Hey. Is it possible to construct partial basement in a house? e.g. covered area of ground floor is 1700sft and we want basement aligning with ground floor walls of 2-3 rooms covering around 400-500sft Is this possible?

    • Mohsin Munir on October 6, 2019

      Yes this is possible and very much in practice😊

      • Kappa on October 6, 2019

        Secondly, Mohsin, I’ve read that there are issues of mildew, extra humidity and radon in basements. How can i counter these 3 issues?

        • Mohsin Munir on October 6, 2019

          All three issues are due to humid environment and improper ventilation. Basements with sufficient sunken areas will never have these issues.

          • Kappa on October 6, 2019

            What do you mean by sunken area?

          • Mohsin Munir on October 6, 2019

            Very simple term, area that is part of basement but is not covered/closed and used for air, ventilation, light etc.

      • Kappa on October 6, 2019

        Mohsin, thanks for the quick replies. One more thing. In case of partial basement, how is the foundation constructed? I mean there would be a combination of brick walls whose foundation made of bricks would be at a different level from the slab foundation of concrete basement. How would this work?

        • Mohsin Munir on October 7, 2019

          If you go through complete episodes of Construction guide field series for basement construction, you will get the answer. I have explained in video how other foundations are constructed.

  • Kausar shabbir on October 29, 2017

    Many thanks. Very useful information.

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