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QUESTION: I have a basement/cellar measuring 25' x 16'. The cellar floor is 5 feet below  the road level. The water table is high in my area, so below 5' I will get water, in summers this will go low to 10' - 12' The house was constructed in 2011. During this year we did not have that good rains. But this year 2013, in Bangalore we've received good rains and the water table has resin and i have at least 8" of ground water in my cellar. Its been closed to 4 months (June - Sept)  I've seen the water recede and rise with intense and light showers respectively.

Since the cellar area is small, I'm planning to buy like 20 - 30 kg of white cement for the floor and plaster the side wall for 2'.

The floor to ceiling height is only 7.5' hence I'm not keen on increasing the floor height and it will beat the purpose of a cellar.

I'm not able to use the cellar and this is causing me great inconvenience. Appreciate your suggestions and thanks in advance.

ANSWER: Dear Mr. Ramesh,

We understand that you find water in basement due to high water table.  

However, we could help you out with specific suggestions if you could share some more details like:

Do you have a Soil Test Report of your Site to establish the Water Tables?

Was the ‘basement’ designed keeping in mind the Water Tables?    

Is it ‘seepage’ or ‘flooding’?  

Whether it is ‘seepage’ or ‘flooding’ can the point of water entry be identified?   

What was the Water Proofing Treatment proposed below the basement by your Architect?

Was the Treatment carried out by a Specialized Agency in a professional manner? Usually Specialized Agencies give guarantee for about 7 years for such treatments.

Is there any way that the Treatment could have been punctured during further construction like Basement Flooring Etc.?  

What is the basement Flooring Finish? Are there any cracks / joints from which water can enter? Is there a Water Proofing Treatment proposed below the flooring?

Do you notice any cracks / settlement inside the basement wall, in recent time?
Etc.    

A detailed site investigation would definitely help in pin-pointing the problem further.

In general the steps for treatment of seepage related problems are well documented:  

1.    First try to prevent the external entry of water seepage into the structure.

2.   Collect all water at the lowest possible point below the basement level.

3.   Adopt dewatering system using High Pressure Pump to pump out all water both in and around basement structure.

4.    Check / conform whether the structure is completely dry before starting any treatment. Treatments in wet-condition are not advisable.  

5.    Leak proofing all around the structure / external peripheral wall - soil stabilization by chemical injection method.

6.    Similarly, soil stabilization below the structure by chemical injection.

7.    One can start now start treatments / injection for the existing walls & floor structure to seal cracks / joints, etc by high pressure injector.

8.    During the entire process (Steps 4 – 7) the De-watering Process should be in operation to avoid any water ingress / accumulation in and around the basement.

10.    After all treatments are complete and cured as per manufacturers’ instructions, the de-watering should be slowly / systematically withdrawn to avoid hydrostatic shocks to the structure.

Steps 1, 2, 3, 8 & 9 could be avoided if the Repairs are taken up during Peak Summer Season, when the Water Table is at its lowest in Bangalore.

We hope that the above answers, your query.


Please feel free to revert,


Indranil Bhattacharya
Architect & Construction Project Manager,
BR Architects & Engineers Pvt. Ltd.,Bangalore  
www.brae.in

 


---------- FOLLOW-UP ----------

QUESTION: Dear Indranil, thank you so much for your reply. Please find my answers below;

Do you have a Soil Test Report of your Site to establish the Water Tables?
RX: I don't have a Soil test report.

Was the ‘basement’ designed keeping in mind the Water Tables?    
RX: Yes we had this in mind.
When digging to lay column footing we got water only at 9 feet and this was done in August (mid rainy season)
To control Seepage and for maintenance we have a 2x2x4 collection tank. This is water proof, meaning even when the ground water was up it didn't seep into the collection tank.

Is it ‘seepage’ or ‘flooding’?  
RX: It's seepage of ground water (sorry if I’m not getting the Jargon correct) Outside water is not entering basement.

Whether it is ‘seepage’ or ‘flooding’ can the point of water entry be identified?   

What was the Water Proofing Treatment proposed below the basement by your Architect?
RX: We used the Liquid water proofing solution that's available at the hardware store and mixed it in concrete. I don't remember the name. I should be a branded one I'm sure.

Was the Treatment carried out by a Specialized Agency in a professional manner? Usually Specialized Agencies give guarantee for about 7 years for such treatments.

RX: The house was done with Labor contract, supervised by my Dad and me. Of course the contractor was an experienced family friend.

Is there any way that the Treatment could have been punctured during further construction like Basement Flooring Etc.?  
RX: The Basement floor is a rough finish, with 6" of big jelly concrete and 2" batani jelly tapper to the tank. The floor and the concrete retaining wall is unfinished. In a way I feel good it’s unfinished because I would not have given the water seepage a thought. Now that I know I can take correct steps.

Another thing. I also have a 3' ring well 10' deep in the basement. I don't think this could impact, it has a 2 ' high wall from the basement floor around it and water is nearly to the brim, this level is above the 8" high of water that is in the basement floor. I can send you a short video of my basement if you'd like.

Chemical Injection could work, but getting the floor 60 - 80% dry is a challenge as it’s been raining for a whole week now. We can drain all the water out though. So will the equipment inject below the 6" think concrete?
How much would it cost for my dimension 25'x16'?

Please let me know if you have any further questions and thanks in Advance

ANSWER: Dated 10th Sept 2013, 6 pm.

Dear Mr. Ramesh,

Many thanks for your reply. I have received most of the answers I was looking for.

Firstly, I would request you to be ‘PATIENT’ and take up the repairs work only during February – March 2014 – i.e. peak summer season in Bangalore, when the water table is at its lowest; this will at least save costs of dewatering of the site. It doesn’t make sense to do something now, which will be washed away the very next day due to heavy rains.    

Secondly, as mentioned earlier, one needs to do a TWO STEP PROCESS.

Step 1:

Stabilization of the soil around the basement by Chemical Injection. In this process, the soil around the building would be converted into a solid mass (almost like rock / concrete)  which will not allow water to ‘seep’ from below the earth.

Step 2:

Making the walls / floor impervious with a high pressure injection system.

Thirdly, at the moment, it is difficult to estimate the costs. It would be advisable (and practical) to study the system more closely for the next 2 – 3 months to gauge the pattern of water ingress, pin-point exact points of ingress to ‘optimize costs of repairs’.

Let's study the system more closely and keep in touch.

Hope that your clear with our chain of thinking and agree on the way forward, for the moment.

Please feel free to RATE us.   

      
Indranil Bhattacharya
Architect & Construction Project Manager,
BR Architects & Engineers Pvt. Ltd.,Bangalore  
indranil@brae.in



---------- FOLLOW-UP ----------

QUESTION: Thanks and i'm so encouraged to share this sort of online help experience with others.
Just a couple more questions.
Will the Chemical injection contaminate the Well water?
The cost estimate will help me decide and plan the professional approach to resolve my issue.

Answer
PU_Page 1
PU_Page 1  

PU_Page 2
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Dated 11th Sept 2013,

Dear Mr. Ramesh,

Thank you for your kind words.

We would recommend ‘Dr. Fixit Two – Component PU Foam Injection Grout’ for
Step No. 1 – Soil Stabilization.

We request you to Contact

Dr. Fixit,
H.V.S. Apartments, Edward Road
BENGALURU - 560 052.
Phone : (080) 22264811, 22205865
Fax : (080) 22281579
Toll free number 1800 209 5504
drfixit@pidilite.com

Kindly request Dr. Fixit to visit the site to give you the most competitive quote. It is better that the entire work – supply of material, application at site, etc. is given to Dr. Fixit  since the same requires high level of expertise and skill.  

Once Step No. 1 is complete, one could look at Step No. 2 at a later date after a gap of 2 – 4 weeks.

Once the material hardens, it is non-toxic and ‘safe suitable for drinking water contact’ as explained in the attached technical data sheet.

Hope that this solves your immediate problems.

Indranil Bhattacharya
Architect & Construction Project Manager,
BR Architects & Engineers Pvt. Ltd.,Bangalore  
indranil@brae.in  

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Indranil Bhattacharya

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Most questions relating to architectural design & contracts management, QA - QC Systems / Standards, On-Site Construction Management, related to Indian Sub-Continent.

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I have been involved in Academics & Practice for the last 15 years.

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Bachelor in Science, Bachelor in Architecture, Master's in Building Engineering & Management

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