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gxross 10-27-2012 05:20 PM

Roofing Fiasco - Concrete
Hi Everyone,

This is a request for suggestions to fix a leaking concrete roof for my 80 year old aunt. She has an old house in hot-humid climate which sees 4 months of heavy rains.
The concrete roof of her house was poured about 25 years ago and is showing severe signs of water seepage. Ceilings show signs of seepage, plaster cracking (stuff falls off), and drip water during rains.

Information that I have collected so far -
1. The roof slope may not have been set correctly 25 years ago (initiating the problem).
2. There was 1st round of plastering - time unknown
3. Later a layer of bricks was added to the roof with plastering - time unknown
4. There was a 2nd round of plastering done - 15 years ago

Seeking your thoughts on -
1. Is this roof repairable (~2000 sq.ft.)?
2. If so, is it advisable to add a layer of plaster with waterproofing chemicals after chipping away the layer of bricks and old plaster?
2.1 What should be done to reinforcement steel bars? Very likely to be rusted ad may have expanded.
2.2 Would plastering of the ceilings (from inside) help?
2.3 What's your take on waterproofing chemicals from companies such as Sika? Would that help in this case?
3. Should a new roof be poured?
4. Are there any other alternatives?

Thanks for taking the time to look at this post.
Appreciate your suggestions and opinion.


oldognewtrick 10-28-2012 07:13 AM

gxross, :welcome: to House Repair Talk!

I would suggest having a liscensed roofing contractor come take a look at the structure. Simply adding more material can cause a catastrophic event. Structures are only rated to carry so much load and failure can occur when you exceed their limit.

Wuzzat? 10-28-2012 09:10 AM

"The life expectancy for a concrete tile roof is marketed as a 50 year roof."

"Concrete tile roofs have experienced 100-year lives in Europe."

I'd hire a consultant to make up a plan of action to fix your 50 ton (?) roof. Then you can get bids from contractors and they would all be bidding on the same task list.

If they have web addresses you can send them dimensions and photos so they don't need to come out to your place, but the winning bidder will need access for his/her large trucks.

nealtw 10-28-2012 09:21 PM

I too would be concerned about rebar rusting. I think your best bet is a local engineer that is aware of the problems found in roofs in you area.

Ttainet 10-29-2012 06:37 AM

Just to add to the other comments, Sika has several lines of roofing and waterproofing products but yes they are very reputable company.

I'm a big advocate of liquid applied waterproofing such as liquid plastics (Sika), or Kemper for low sloped or zero slopes roofs but the substrate would have to be looked at to ensure compatibility. I would think the layers of brick and plastering would need to be removed but your licenses waterproofing consultant or contractor would know best.

gxross 10-30-2012 11:31 PM

Hi Everyone,

Thanks for responding to the post. Appreciate the help!

I think I will get a local civil engineer to conduct an inspection and assess the extent of damage.


nealtw 10-30-2012 11:45 PM

Good plan and good luck. Keep us posted.

oldognewtrick 10-31-2012 02:09 AM


Originally Posted by gxross (Post 79298)
Hi Everyone,

Thanks for responding to the post. Appreciate the help!

I think I will get a local civil engineer to conduct an inspection and assess the extent of damage.


I would suggest calling a structural engineer, not civil.

Wuzzat? 10-31-2012 11:40 AM

Structural, civil or mechanical. There must be some overlap with their education and experience.

nealtw 10-31-2012 12:53 PM

Most are pros and will send you in the right direction to get what you need.

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