Terrace area crack filling || Waterproofing

[venk_pr]

Dear Nivas,

My sincere Thanks once again for taking time to give quick feedback.
if u don't mind, what do you do for living? your profession?
I appreciate your help a lot, You are a credit to this forum.
Please keep up the good work and contribute more to this forum.
Regards
Venki

[prakashn]

Dear Nivas,

Kudos to you for sharing your expert advice for the benefit of thousands of advice seekers like us. I'm a new member to this forum and i too am seeking advice regarding Terrace Waterproofing and so turned to the net for unbiased expert advice. I've followed you on this particular thread and there has been a lot of similarity between you'r advice and an Engineer's here.

My house is a 2 storied, 30-32 yrs old house. The RCC Slab had Brick-Bat-Coba, cement plaster and finally 6x10 inches (5x10 nowadays) clay water/weather proof tiles on top. For a 1750 SFT area it had only 3 drain pipes. Since the last 5-6 years there has been dampness and paint peeling in the ceiling. This yr we decided to renovate and on the advice of 3 Engineers dismantled the brick bat coba and tiles. 80% of it has been cleaned. At some place the Brick Bat coba is hard and stuck to the slab. The engineer's mentioned brick bat coba being an old method is replaced nowadays by 12mm concrete screed. We agreed and then started my confusion. Which waterproofing?

1) Clay tiles on the screed(my choice, i believe they are natural water-proofers cum insulators) or
2) Brushbond RFX before laying the screed (Eng.1's choice) or
3) Dr. Fixit Newcoat after laying the screed(Eng.2's choice) or
4) Just the 12mm Concrete Screed(follow the Step C in its entirety (C1,C2,C3)) and few yrs later if required get it coated with Dr. Fixit (my Dad's choice).

Adding to the confusion is, what needs to be done for the through-and-through cracks(4-5) that have formed along the lines of the electrical piping. Among the 5 cracks water seeps freely through one(observed that while cleaning) since its in a lower level although its a flat Slab.
Eng.1 advised to make a 8mm Reinforcement frame of 1 feet width along the crack. Apply Nitobond EP on the mother slab and then lay the frame and concrete.
Eng.2 advised to ignore as the 12mm concrete screed will fill and take care of it.
My contractor too advised as per Eng.1. He said the cracks on the mother slab will surface up on the screed eventually but with reinforcement it may not.

I haven't seen any info on water proofing clay tiles and so I would like your expert advice on these issues at the earliest as possible. It's the start of the summer rains and need to decide and implement quickly.

Thanking you!

[Nivas]

In my opinion , do not go for tiles of any sorts for waterproofing. Reason : tile joints are the weakest ,water permeates through clay tiles.
Go with Eng 2 advice , lay the screed . For through and through cracks , I am assuming it is more than 5mm. you need to buy Fosroc GP2 . It is a cementious material with high plasticity meant to flow into the cracks by itself ,ie with no external force. Add some SBR and water to GP2 and pour it over the cracks , it will flow through cracks and seal . It will cure hard. after that lay the screed with waterproofing as explained.
Good luck

[prakashn]

Hi Nivas,

Yes, I have decided to lay the screed and then waterproof it with Dr. Fixit Newcoat or Fosroc Roofguard.
The through and through cracks are 1 to 2mm max but seepage happens through one of them. What steps for these then?

In the Concrete Screed laying step, the contractor and workers don't actually mix SBR, water and cement in the same proportions and manner as per the company's usage ratio, do they? It is unknowingly or knowingly diluted and not mixed well too even after repeated instructions.. I guess it jus happens in an ideal world. How to over come these flaws?

Which is the better company/products? Fosroc or Dr. Fixit? Nitobond SBR or Pidicrete URP, Conplast X421ic or Dr. Fixit LW+, Dr. Fixit Newcoat or Fosroc Roofguard?
Are there two types in SBR: Nitobond SBR and SBR Latex?

Please share Chirag Agencies (Fosroc) contact please? Also info on the best rates provider for both Fosroc and Dr. Fixit products in Bangalore would be highly appreciated.

Thanks and regards
Prakash

[Nivas]

sorry its chiranth not chirag . you can buy fosroc from them, justdial for ph. for BASF and ardex u can contact snenterprises (website). above are distributors prices are standard. check for old and new stock. local cement dealers also can give u a better discount by evading tax. pidilite \ roff may work out cheaper.
quality wise they do not differ much , its ur choice. i prefer fosroc.
yes do ur homework , slight dosage deviation is fine, its a trade off b/n quality and cost .remind contractor about the process with impetus on mixing, supervise and micromanage. homogeneity and mixing should be not be compromised. ensure ur screed finish is rough(sponge finish with broom) instead of smooth floor finish. divide ur roof and mark 1.5 or 2 sqft squares with twain while its wet . ur contractor understands what it is.

i prefer roof guard, choose white , it is high albedo with good SRI, under intense sun you walk on screed and after paint is laid\ walk on it, u will notice that the roof never heats up leading to cooler roof. ie hot roof around 50 deg c , white roof around 35 deg c . cost may be close to 40-50 rs per sqft for 3 coats with labour and material. 20 liters may cost around 7k.
pm me when u get to this stage , will give u skilled labour contact , 10-12 rs/sqft for 3 coats with surface cleaning.

[Nivas]

for got sbr latex is high solid emulsion , sbr is low solid . former being superior and costlier.

[pv_prasanna]

Hi Nivas,
The mother mould in bathrooms have been given the traditional waterproofing coating consisting of fine sand and cement with Dool cement on the top along with Fosroc Conplast addative (called as oil) He has used 53g Birla super for this coating. I am thinking of applying brushboand RFX over this coating after 3 days of curing. Our mason says that there is no need to do brush bond RFX on this. Is this required? After this, the plumber will lay the sewage pipes and after the pipes are laid, I intend to put lightweight bricks and a mixture of cement, sand and 12 mm metal (batani jelly).

[pv_prasanna]

Nivas can you please call me pr send me a message on nine six two zero three one two five two nine.

[Nivas]

sorry for late reply , the oil , or the brown liquid conplast\pidilite LW+ \roff are lignosulphonate class additives , they are plasticizers they work by 3 ways making the concrete less porous or less permeable ,homogenizes the concrete mix and u require less water to achieve certain plasticity which will increase strength of concrete. all these are desirable for a concrete mix. now with this compared to non additive concrete , u will be able to reduce porosity , its not water proofing . then u need a elastomeric or epoxy coating depending on how deep is your pocket , RFX is a 2 component acrylic based cementious elastomeric coating . it forms a lasting thick barrier , which achieves ur 70% water proofing. while protecting ur rebar from rusting screening chloride and sulphate ions. the dool cement layer on top is just your masons imagination, it is no barrier.
the above information is derived from the company's leaflet. i suggest u go with both.

[Visualizer]

Nivas how about using densifier / crustalizer such as Lithium Silicate.
Will application of lithium silicate based crustalizer help making terrace water proof ?