Q&A / 

How to Repair Leaking Concrete Deck

Quick Column Summary:

  • Cracked concrete roof deck is leaking
  • Are silicone and hydrolic cement needed
  • Do not use silicone, use Epoxy
  • Then a concrete overlay

Libbie, a handy woman hailing from Port Alberni, British Columbia, Canada - our northern ally - emailed me with a great message. Read it for yourself:


Love your videos: I am a pensioner (gal) with limited physical ability ~ BUT ~ consider myself able to do a lot of handy work, the house (1967) has a concrete deck on the second floor (! yes) and I have water ingress issues into the garage area below (through the joists I think) via  one minor crack on the surface and  crumbling flashing at the edge of the deck. This seems to occur when the snow melts on the deck (yes, I have gone out in the middle of the night to brush the *#*# white stuff off!)

 I need to know if I have to inject silicone into the cracks (some approx. 12" deep) and then use a hydrolic cement patch product. I do not have the $ to remove the cement and replace with a wooden deck: I live in a rainforest area. Help me OBeWan!  I LOVE your website and concise way of teaching. Thank you so much."

Libbe, the LAST thing I would inject in that crack is silicone.

I've written extensively in the past about EPOXY injection materials for concrete cracks.

Type: CONCRETE EPOXY CRACK INJECTION into my search engine.

To get these magic products to work, you need to make sure the crack is wide enough to accept the material. Hairline cracks don't play well with the epoxy injection materials. The epoxy manufacturers will tell you the MINIMUM crack width.

There are MANY epoxies to choose from.

Now, here's another option, and this one may push your personal handy envelope.

After you've repaired the crack, what about putting an asphaltic membrane on the concrete and then pouring a 1-inch concrete overlay on the deck to ENSURE you now have great positive drainage away from the house?

Type: concrete overlay into my search engine and read all my past work on this topic.

Think about it.....


4 Responses to How to Repair Leaking Concrete Deck

  1. Dear Tim:

    I love your solutions to problems and have used quite a few of them myself and passed others on to friends. Now I have one I don't remember that you addressed and I'm sure there are others out there with the same problem.

    I have a concrete driveway that is on a slight incline and 80' long x2 car wide. It has some wide, somewhat deep cracks but no crumbling of the concrete. I have been told to cover it all up with black top but I don't want to see this huge black surface. Is there any way to repair the cracks and make it look nice without spending a ton of money? I'm on a fixed income and a lot of money isn't available.

    Thanks for your help - vera

    • Vera, I don't know what I'm going to do with you. In all the time you took to type your issue, you could have had your answer. All you had to do was type into the SEARCH BOX at the side or BOTTOM of any page here at my website. Just type: "repair concrete crack"

      When you do, you'll see past columns come up that talk about "concrete epoxy". Always always type in your keywords into my search engine. Get back if you can't locate them.

  2. Libbie.....I am curious if you fixed your concrete deck. I am a similar issue with my concrete deck. It is above a carport and leaks. I had a concrete specialist come last year and use an epoxy product all over the deck. The product was supposed to be guaranteed for 3 years and the labour for a year. Just before a year was up it started leaking again! I have not heard back from the company yet. right now my deck is covered with a big tarp for the winter to help. I spent $4000 to 'fix' it so am curious what else I can do. Let me know if it worked for you.
    And Tim...thanks for a great website!

  3. hey... I have a concrete deck that started cracking on the vertical 2' perimiter. I grinded and chisseled out all the concrete on the vertical perimiter and can see the deck has steel roof deck material that the concrete deck is poured on. In the channels of the roof deck that are not touching the (perimiter) foundation wall, insulation is shoved in there. I was thinking of taking out the insulation, going into the home and boarding up the holes, then pouring concrete from the exterior with forms to hold the concrete on the exterior. I'll use some chicken wire for strength and allow 3/4" so I can do a stucco like finish (parge) on the exterior to match the rest of the concrete that is not touched. will this solve my cracking issues or what are your thoughts ?

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