Waterproofing a cement roofdeck

[Raisedroof!]

Hi, my friend have a three-storey house made of cement with roofdeck. He often talks about how he experiences water leaks appearing as water marks on his painted ceiling on the top floor, whenever there's rain. He said he had been applying the paintlike waterproofing on said deck but has become too engrossed on it once every year. After finding and browing through this site, I found the forum an opportunity to learn about the types/kinds of waterproofing materials available in the market. I'd be grateful if there is anybody who can give me advise on what brand/make/process of hi-quality waterproofing and long lasting for a cement roofdeck of about 150 sqm. Anyone? tnx

[bbn]

Consider epoxy. It is expensive but it is durable and definitely watertight.

I'm a big fan of Cord. I've used their products for saltwater tanks and on my boats. I am sure their application engineers would be happy to discuss your options with you. I think they can even contract the work and give you a guarantee.

[2diy4]

The big problem about waterproofing is movement of the surface on which it is applied. Some of the hard waterproofing products like cement based products will crack if the concrete on which it is applied cracks. Then leaks start again.

Cracks occur more regularly where a roof deck meets a wall. In instances where movement is expected, the best waterproofing will be those that are flexible. Some elastomeric paints are guaranteed to be flexible.

For really tough jobs, I suggest for your friend to bite the bullet and invest in hot applied rubber or asphalt type waterproofing. The sheets are fused together and to the roof surface with heat. And the asphalt will be flexible enough over the cracks.

There are many suppliers of this type of waterproofing as it is not really a DIY operation. But ask your friend to get referrals and guarantees.

[bbn]

2diy4 is right about your needing flexibility which epoxy may not live up to. Also, the UV will destroy the epoxy so it would need a topcoat.

[Raisedroof!]

Thank you guys for the inputs. I just visited an ACE hardware near our place and found out from a sales clerk that there really are different kidns of sealant for every surface i.e., metal, wood, plastic, cement, etc., not to mention the type of materials used as base material for sealer. There are also surface sealants as well as mere joint sealants, the signs on the can also states that it is A waterproofing sealant. Honestly? I am awed by a variety of sealants you can buy, and if you are not a discerning buyer, those sales clerks can take you for a roller coaster ride. Nonetheless, I found what I am looking for that costs about P2,400 per pail. Is that masonry sealant good enough to last a few years?

[fortuner13]

sir try this one.....

http://www.dexterton.com.ph/view_product_details.php?edp_code=04092-08010&cat_id=4&subcat_id=20&subtype_id=78

[Raisedroof!]

Nice link, good site, thanks fortuner13

[tatoski]

For long term use, hot applied membrane waterproofing is the way to go. Some even have gravita (little gravel) on one side to act as non slip if the membrane will not have a topping or pavers on top.

[Bobby]

For DIY applications on your roofdeck waterproofing, i recommend using Flexseal elastomeric paint. 7 coats is sufficient to waterproof your deck. There are new types of elastomeric paints out there in the market today but none of them are recommended and advised to be used for waterproofing your deck roof. Try buying two different colors of flexseal then alternately applying them on the whole deck roof.

[Raisedroof!]

Hi Bobby, Is this the same with that I found/saw at Handyman, branded as "Thoroughseal" that is supposed to be in powder form, stuffed in one gallon can container? The Sales Clerk says it needs to be dissolved with right amount of water and applied on roofdecks? I am aware that there are many brands, and makes of waterproofing material, and now, even DIY-friendly. Is it?

[manmantandoc]

i recently had my roof deck fixed since the original contractor obviously did a very lousy job. another contractor also gave me a quote to do the job for 25k.

first step was for me to patiently remove the existing waterproofing paint applied by my old contractor.

second was to trace the cracks on the cement roof that caused the sipping of water to the 2nd floor.

third, after marking with a chalk the cracks, i used a grinder to make the cracks a little bigger in a "V" shape about 1cm deep.

fourth step was i vacummed the cracks and cleaned it thouroughly to make sure their were not dirt left.

fifth, i used a commercially available hydraulic cement to seal the "V" cuts. Hydraulic cements dry very fast and application has to be fast. correct powder & water combination must also be obeserved.

sixth, after making sure that all cracks are sealed with hydraulic cement, i placed a layer of vulca seal as reinforcement. i was suppose to use asphalt but i did not know where to buy.

seventh, after the curing of the sealant , i re-cemented the whole roof deck with an inch of cement ( make sure you do this when its not so hot & humid since the first time i did this, it was during the hottest day in Manila and the cement dried so fast and in just a few days, cracks emerged so i had to do it all over again). Make sure also that the clevy of the re-cementing is perfectly angled to the drain/s. make sure also that you make the old cement a little rough ( i used a grinder) to amke sure that the new layer of cement will have a good grip.

eight,i re-painted the newly cemented roof deck with a commercially available elastomeric paint. i applied 6 layers and made sure that the corners & sides had thicker coatings.

it has been 6 moths and i never had any single "tulo".

i plan to do a recoating of the roof afer the rainy season.

i only spent around 7k for everything including labor.

i hope this helps. ;D

[2diy4]

Congratulations on a good job. What brand elastomeric paint did you use? I'm thinking of doing a test on elastomeric paints and knowing brands popular with members will help me. Can someone help out with possible tests? I think it was bobby who mentioned painting the elastomeric paints on a sheet of hardiflex pour water and see results. There was also a suggestion on making a cardboard box, painting the inside with several layers, then pouring water.

[manmantandoc]

the brand i used was a-plus sir...............pretty good.........well at least as of this moment ..............but i plan to paint another coating and maybe i will try flex seal as recommended by one of our friends here in pinoy handyman...........

[jasonub]

The problem with asphalt is it cracks. even the blowtorch membrane cracks in time and though its the most accepted, it does work for awhile.

Asphalt based products when subjected to heat tend to crack after awhile.

Also it has a tendency to delaminate (kapak) then when it becomes brittle, it cracks and water will seep in.

you can use our waterproofing product called primedri fwm which is flexible, adheres to most if not all surfaces, durable and uv resistant if not uv proof.

[koykoy]

hello!

how about covering it tiles? would they prevent water?

[Bobby]

Thoroseal is a cementitous type of waterproofing and I personally would not recommend that type of waterproofing on your roofdecks cause of surface movement. Cement = hard so movement = cracks.

Another thing is epoxy is never recommended on waterproofing of roofdecks. Yes, it is good for cistern tanks coz it comes out with a tile like finish - but remember that tanks are not exposed to uv rays and epoxy generally deteriorates on uv rays (you can ask the distributors themselves and they will tell you that).

Tiles does not in any way affect waterproofing. Even using a good sealants on gaps and fills would not affect it. I really recommend Flexseal to waterproof your deck roofs coz it is the only brand in the market today that specifically says it is used for it (not one of the other elastomeric paints in the market recommends it for deck roofs) - you can ask the dealers about this.

[koykoy]

Flexseal ba is from Boysen?

How about a cementitious waterproofing additive applied as a plaster on top of the roofdeck?

[fgvillegas]

Thoroseal is a cementitous type of waterproofing and I personally would not recommend that type of waterproofing on your roofdecks cause of surface movement. Cement = hard so movement = cracks.

Another thing is epoxy is never recommended on waterproofing of roofdecks. Yes, it is good for cistern tanks coz it comes out with a tile like finish - but remember that tanks are not exposed to uv rays and epoxy generally deteriorates on uv rays (you can ask the distributors themselves and they will tell you that).

Tiles does not in any way affect waterproofing. Even using a good sealants on gaps and fills would not affect it. I really recommend Flexseal to waterproof your deck roofs coz it is the only brand in the market today that specifically says it is used for it (not one of the other elastomeric paints in the market recommends it for deck roofs) - you can ask the dealers about this.

Can I still cover the roof deck with tiles after applying Flexseal?

[opzuk4x4]

Boysens' Plexibond is specifically designed for Roof decks and Firewalls. IMHO is better than elastomeric paints.

[fgvillegas]

Has anyone tried Power Mix?

My contractor is going to use this to waterproof my deck. He said it is both cementitious and flexible. He will apply this before covering it with cemment and tiles. As for the number of coatings, I will still have to ask. But your recommendation is very much welcome.

Thanks.

[jhun]

Me i've tried "Powermix" and a similar product, "AllWeather Concrete Bond". I've tried them both in roofdecks in separate occasions and they performed well. Hanggang ngayon wala pa rin tagas. They are mixed with cement at certain ratios. I've noticed one time may leftovers na napadikit sa plastic cover nila at natuyo, nun pi-neel-off ko sila, I've noticed the film (a mixture of cement and the liquid) is really tough and flexible, parang elastomeric sheet.

[rprod]

Boysens' Plexibond is specifically designed for Roof decks and Firewalls. IMHO is better than elastomeric paints.

Had a problem with this product. Leaks re-appeared even after applying 3 coats in our roofdeck
. :(

BTW, does anyone here know the supplier/distributor of FlexSeal? Please include also where I can buy fiberglass membrane & industrial rubberized elastomeric sealant/paint.

I'm having our roofdeck re-waterproofed. Cheapest quote that I got from Contractors is P 47 K (Labor & Mat'ls). I might spend less if I buy the materials & just hire skilled painters to do the job.

Would appreciate anybody's help. :)

[bryant77]

Had a problem with this product. Leaks re-appeared even after applying 3 coats in our roofdeck
. :(

BTW, does anyone here know the supplier/distributor of FlexSeal? Please include also where I can buy fiberglass membrane & industrial rubberized elastomeric sealant/paint.

I'm having our roofdeck re-waterproofed. Cheapest quote that I got from Contractors is P 47 K (Labor & Mat'ls). I might spend less if I buy the materials & just hire skilled painters to do the job.

Would appreciate anybody's help. :)

Flexseal ------> Campbridge waterproofing System Inc.

Head Office
1370 JOSE ABAD SANTOS AVENUE, METRO MANILA, PHILIPPINES
TEL NOs: 252-0531 (connecting all departments)
FAX NO : 252-0551

Branch Office
1390-A G. ARANETA AVENUE, QUEZON CITY, PHILIPPINES
TEL NOs: 414-5096, 412-0344

I ordered directly to them. They give discount on volume order. You can contact them for technical support on its application.

If several gallons lang sa distributor/hardware ka na lang umorder.

http://www.campbridge.com/Distributors.html

I haven't tried flexseal on roof deck but they recommend several coatings plus the mesh membrane to bridge the crack.

If your going to waterproof the roof deck you need to removed the concrete topping and existing waterproofing. Clean the concrete surface, apply primer then several passes of flexseal. Lastly new concrete topping to protect the waterproofing from human traffic.

[rprod]

^^Thanks for the tip Sir! May I know what you use for waterproofing? Do you have any idea how much Flexseal I will consume for a 50-sq. m. area ?

[bryant77]

^^Thanks for the tip Sir! May I know what you use for waterproofing? Do you have any idea how much Flexseal I will consume for a 50-sq. m. area ?

I used 3 ply waterproofing membrane (hot applied), 1 roll = 8 sq.m less than P4,000/roll. Eto lagi kasi nasa construction guidelines & recommendation ng mga building admin/owner sa mga projects that we handle. I have no choice but to follow.

I'm using Shell flintcote black primer 2-3 coats, then apply membrane using LPG torch to heat the underside. You need to conduct 24 hrs flood test, cover all the drain and pour enough water. Pag wala ng leak sa underside ng concrete slab, saka pa lang mag lagay ng concrete topping.

[rprod]

Now I'm confused what to use. :confused: Should it be elastomeric paint + membrane or torch-applied membrane? Actually I talked to a number of contractors already & they all have different suggestions.

Gusto na kasi namin na sigurado yong waterproofing ngayon. We've been disappointed w/ the past jobs already.

Contractor ka pala Sir. Thanks for taking time to answer my queries. :)

[andres_88]

^^Thanks for the tip Sir! May I know what you use for waterproofing? Do you have any idea how much Flexseal I will consume for a 50-sq. m. area ?

For a 50 sq.m. roof deck, you may need around 18 gallons of FlexSeal. Buy two colors like black and terra cotta so that you would know if you totally covered previous coating. Give an interval of 4 hours drying time (8 hours is best).

What we usually do for our project is this system:

1. Coat all area with FlexSeal Terra Cotta.
2. Then with FlexSeal Black.
3. While the coating is still wet, lay a sheet of polyester reinforcing mat - then coat with Flexseal Terra Cotta.
4. 4th coat - Black, 5th coat - Terra Cotta, 6th coat - Black.
5. And finally 7th coat FlexSeal Terra Cotta - and while the coating is still wet - introduce fine grain sand on the surface - the reason is that the sand will increase bonding with your concrete topping later.
6. Allow a few days to let the waterproofing dry completely, then flood test it.

Hope that helps.

If you have more question, dont hesitate to call Campbridge at 252-0531. Or email me andy@campbridge.com.

Peace :)

p.s. the material cost will be around P 8,550.

[balarila]

Re-asking in this thread as there may be new suggestions.

I have a 4 decks/balconies in my house, all with Mariwasa tiles and all, after 7 years are leaking. Didn't know whit about waterproofing when my house was built so can't tell you what the contractor used but I recall he painted something reddish that he says ends up rubbery, then topped with tiles the normal way.

Initial problems we had were leaks where the drains are. We had to dig out the drains covers, reapply this magic reddish goo, then reinstall the covers.

Next summer, we plan to tear out all the tiles and apply waterrpoofing since our ceilings have ugly water spots already. This is a costly and grossly inconvenient activity so would appreciate advice on how to do this for good.

[zepol]

@balarila

sayang naman yung tiles. Unless the tiles are cracked, they're waterproof. The leaks are likely to be in the grout, the spaces around the drain, and the borders between the floor and walls.

Maybe it's possible to re-grout the tiles, then use a grinder to remove concrete at the borders of the walls and around the drain, and also remove the cracked tile. After that you can apply waterproof cement to seal the borders and fill the cracks ( I've had good results with waterplug ). Basically, you replace the exposed concrete with hydraulic cement (and that includes underneath the drain covers). That waterplug's expensive, but it works.

I've avoided having to remove some compromised concrete topping by grinding out the wost spots and applying waterplug in strategic places, the stuff flows inside the spaces and expands. Kung baga, it goes where the water goes, then turns into cement.

Also, you might consider applying cementitious waterproofing to the walls around the balcony as well, baka naman the leaks are through the walls via osmosis.

This might not work, but considering the cost of tiles, it might be worth a try.

BTW, the waterproofing method i picked up from this forum works. First fix cracks with hydraulic cement, then thoraseal or mortarseal on top. Over this goes flintkote, then polyurethane matting especially the corners, then more flintkote. Once the flintkote's bone dry, concrete topping. The first layer will almost do the job, but any shifts in the concrete or cracking will negate this, that's why the bitumen layer goes on top, to bridge potential cracks as well as decrease the hydrostatic pressure. The polyurethane matting gives the bitumen tensile strength, and facilitates removal of the bitumen 10-20 years down the road if maintenance needs to be done.

I'm a bit wary of rubbery waterproofings. No waterproofing lasts forever, bitumen gets washed away, cement-based waterproofing cracks. But you can patch cement based waterproofing, and bitumen can be washed away or cemented over. But that rubbery stuff might have to be ground away when it fails.

Anyway good luck!

[Armand]

For a 50 sq.m. roof deck, you may need around 18 gallons of FlexSeal. Buy two colors like black and terra cotta so that you would know if you totally covered previous coating. Give an interval of 4 hours drying time (8 hours is best).

What we usually do for our project is this system:

1. Coat all area with FlexSeal Terra Cotta.
2. Then with FlexSeal Black.
3. While the coating is still wet, lay a sheet of polyester reinforcing mat - then coat with Flexseal Terra Cotta.
4. 4th coat - Black, 5th coat - Terra Cotta, 6th coat - Black.
5. And finally 7th coat FlexSeal Terra Cotta - and while the coating is still wet - introduce fine grain sand on the surface - the reason is that the sand will increase bonding with your concrete topping later.
6. Allow a few days to let the waterproofing dry completely, then flood test it.

Hope that helps.

If you have more question, dont hesitate to call Campbridge at 252-0531. Or email me andy@campbridge.com.

Peace :)

p.s. the material cost will be around P 8,550.



I might give this approach a try next year. My 4-year old house has leaks too on the apprx. 40 sq. ft. front deck that even numerous repairs didn't yield good results..kbwisit lang tignan ang loob ng bahay.
https://lh6.googleusercontent.com/-nDiiLE52Ajc/TuABdr2nIvI/AAAAAAAABz4/3IOXRcQyl4I/s512/120820111137.jpg

[pinoychem]

Re-asking in this thread as there may be new suggestions.

I have a 4 decks/balconies in my house, all with Mariwasa tiles and all, after 7 years are leaking. Didn't know whit about waterproofing when my house was built so can't tell you what the contractor used but I recall he painted something reddish that he says ends up rubbery, then topped with tiles the normal way.

Initial problems we had were leaks where the drains are. We had to dig out the drains covers, reapply this magic reddish goo, then reinstall the covers.

Next summer, we plan to tear out all the tiles and apply waterrpoofing since our ceilings have ugly water spots already. This is a costly and grossly inconvenient activity so would appreciate advice on how to do this for good.

let me quote you from another thread:

Sorry, let me correct myself. I get fiberglass cloth from Polymer; I have friends who buy their epoxy resins (for boatbuilding).

They sell resins in two parts by the gallon. Each gallon is about P1.5k+. Ratio of mixing is 1:2. But epoxy resins shrink. That's why we pour them proud when filling gaps or holes (e.g. making bushings).

In another message, you mentioned polyurethane as deck waterproofing. Why not epoxy? (question, not a suggestion).

You are right that this should be in another thread. There is one here. Do you mind posting your suggestion re waterproofing in that thread?

I have a lot of tiled decks in my house and many are leaking. I will probaly have them torn off next summer and put waterproofing. Since this is a costly and grossly inconvenient exercise, I'd like to do it right and for good. Thanks.

the suggestion to remove your existing tile grout and re-grout is a good one. specially if only a couple of tiles are loose. then you can seal the new tile grout with clear acrylic sealer as added protection.

also don't forget to completely waterproof you roof deck walls (parapet).

the reason why epoxy is not recommended for roof deck waterproofing is because it yellows and possible to chalk under direct sunlight. aliphatic polyurethane has excellent UV or direct sunlight resistance.

let me suggest as early as now, you can ask several waterproofing contractors (get referrals from younger engineers and architects you don't know) to take a look and submit quotations. ask each of them to quote at least 2 different waterproofing systems plus applied samples and technical data sheets of the product they intend to use.
their visits and quotations are free.
don't forget to ask for their projects references. your best bet would be a company that has been around for more than 10-15years and have done several big waterproofing projects.

then come summer time, choose the best waterproofing system you can afford and ask for the longest warranty - say 10years.

[pinoychem]

you may want to check out polyurethane waterproofing:

http://www.philpu.phpnet.us/

thanks!

[balarila]

Thanks. I'm familiar with epoxy on wood (and pu) but not sure about application on concrete sandwiched between tiles. I'm aware that epoxy is used in repairing pavement cracks but not sure if the epoxy resin I use (on boatbuilding) is the same.

Also, epoxy is very expensive. And, not sure how concrete would absorb it. If concrete sucks it like a sponge, it'll cost quite a bit.

On PU waterproofing, I'd use it only on areas not fully exposed, since, from my experience, they do wear out after a few years. I'd prefer epoxy as primary waterproofing then PU was UV protection.

Will take your suggestion on asking contractors and references.

[zepol]

@bala
could it be that the leak's in the fittings of the downspout? i've had that problem.
Posted via PHM Mobile

[pinoychem]

torch membrane is a good waterproofing material


http://philpu.phpnet.us/notorch.htm


but i recommend something seamless

[bmac]

must be concrete roofdeck not cement