# Need advice about waterproofing a firewall.



## angelo07 (Jan 1, 2010)

Hi there,

I have a problem with our house firewall. This last wet season where heavy rains dropped, i noticed that water leaks in most part of firewall to the rooms. The firewall is already painted with white ( i don't know if what kind of paint is it.) I am based from the Philippines. Any permanent solutions you can suggest to solve the problem. Thanks...


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## clasact (Oct 21, 2006)

find out where the water is comming from and divert it away


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## angelo07 (Jan 1, 2010)

I need a permanent solution, and it happened the firewall seems like there are some hair thin like cracks that most likely the passage of water. I need what is the most appropriate solution for it. Like paint or any much better solutions. Thanks..


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## ccarlisle (Jul 2, 2008)

I don't know what you mean by 'firewall"...can you explain?


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## angelo07 (Jan 1, 2010)

ccarlisle said:


> I don't know what you mean by 'firewall"...can you explain?


Basically it is a concrete wall happen to be much taller/higher than the roof's height. Its main purpose is to protect the house from fire when it happens on your neighborhood. 

Basically, my problem is a concrete wall which is already painted and needed to be wateproofed. I am opting to get some advices in the net but there is none to avail that I think is credible. So anyone here who is expert on concrete/construction, please help. thnaks..


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## ccarlisle (Jul 2, 2008)

Oh I see...we have "firewalls" here between row houses, exactly for that purpose (to protect you against your neighbours' fire) but we use ciment blocks capped with aluminum flashing to prevent water infiltration, say from rain or snow.

Flashed to the roofing membrane, that's the only part of the firewall, about 12" high, that we treat against water. Are you also saying the small cracks are way up high or in the rooms too? what is cracking... the cement itself? or a coating of some kind?


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## tpolk (Nov 7, 2009)

a firewall or partywall used in multi use residential like that usually goes thru the roof as you said. The water is most likely coming thru at the roof, either shingles, flashing, stucco or combination of all three. Paint and caulk below roof wont help, you need someone who knows roofing to go up top and look for the problem


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## angelo07 (Jan 1, 2010)

Cracks I think is booth inside and outside the wall. I posted a video on youtube during a hard rain where water is leaking into the wall.

http://www.youtube.com/watch?v=s7SRoKbc8oA 

That is inside the room's wall. There are also cracks, though thin still water leaks. 



ccarlisle said:


> Oh I see...we have "firewalls" here between row houses, exactly for that purpose (to protect you against your neighbours' fire) but we use ciment blocks capped with aluminum flashing to prevent water infiltration, say from rain or snow.
> 
> Flashed to the roofing membrane, that's the only part of the firewall, about 12" high, that we treat against water. Are you also saying the small cracks are way up high or in the rooms too? what is cracking... the cement itself? or a coating of some kind?


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## angelo07 (Jan 1, 2010)

I already asked some engineers whom i known and one suggested me about the product Thoroseal. He said it is ideal to apply on my exterior firewall which is already painted. But looking to its main website, it says there that is must NOT be applied to painted surfaces. Here is a link on the product.

http://www.thoroproducts.com/pdf_appl/appl_super_thoroseal.pdf

I am looking for similar thing that could work on painted surfaces. I already searched about waterproofing paints but someone advised me that is not a suitable solution. It won't last long.



tpolk said:


> a firewall or partywall used in multi use residential like that usually goes thru the roof as you said. The water is most likely coming thru at the roof, either shingles, flashing, stucco or combination of all three. Paint and caulk below roof wont help, you need someone who knows roofing to go up top and look for the problem


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## clasact (Oct 21, 2006)

hence find out where the water is comming from and divert it away (fix the problem dont just try to cover it up with some sort of sealer that wont work or stop it).So as tpolk said get someone up their to find out where the water is getting in and fix that before you go to trying to waterproff the block wall


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## angelo07 (Jan 1, 2010)

Ok. Can you suggest products for waterproofing that are effective?



clasact said:


> hence find out where the water is comming from and divert it away (fix the problem dont just try to cover it up with some sort of sealer that wont work or stop it).So as tpolk said get someone up their to find out where the water is getting in and fix that before you go to trying to waterproff the block wall


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## clasact (Oct 21, 2006)

redgaurd is good stuff but it aint going to fix your problem


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## tpolk (Nov 7, 2009)

a good waterproofing material to start with would be a ROOFER


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## joemarcial (Jan 14, 2021)

angelo07 said:


> I need a permanent solution, and it happened the firewall seems like there are some hair thin like cracks that most likely the passage of water. I need what is the most appropriate solution for it. Like paint or any much better solutions. Thanks..


had the same problem, water going thru the cracks are coming from the tip of the firewall, wall cap should do the trick.


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## Nealtw (Jun 22, 2017)

joemarcial said:


> had the same problem, water going thru the cracks are coming from the tip of the firewall, wall cap should do the trick.


Watch the dates on the thread, once they are most of a year old, we ignore them.


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