How to waterproof top of garage?

[Farid]

Our full brick 2 storey house has northerly aspect with driveway & garage occupying the NE corner of the block. I have water seeping though the garage's concrete top along the eastern wall as seen in these photos.

 Middle Back wall  

The photos below suggest that there are obvious entry points for seeping from water pooling at the top of the garage and from garage window's sill. 

    

I have three questions
What is the best way to prevent these seepages?
How do I waterproof and paint the garage walls?
Any ideas for drainage and better use of the area on top of Garage (900mmx 6500 mm)

Much appreciated.
Farid    

[EricL]

Hello @Farid 

Welcome to the Bunnings Workshop community. It's marvellous to have you join us, and thanks for sharing your question about your garage wall.

I'm afraid the leak happening to your wall is quite severe and no amount of sealer will prevent the water from coming through. I suggest engaging the services of a registered builder and have the leak from your windowsill and possibly the roof repaired first. 

Sealing the wall with product at this point will be just a waste of material as the water will simply push any paint or sealer off with hydrostatic pressure. If left unrepaired the water start to eat into your brick wall and compromise its integrity.

Once the leak is repaired you should start to see your wall dry off, and that dark hue will start to fade going back to its original concrete grey. This would be an excellent indicator that the water is no longer flowing into your wall and then you can make plans to paint it.

If you have any other questions we can help with, please let us know.

Eric

[Farid]

Thanks @EricL for a valuable advice. I was hoping for a DIY response but I appreciate your guidance for an expert review. 
I thought of improving drainage and waterproofing the top of the garage, repairing the window sill and applying waterproof membrane on the external garage walls will stop these seepages and would allow me to tackle cleaning and painting the internal wall.  
Cheers
Farid

[MitchellMc]

Most of the water penetration is likely through the roof @Farid. Waterproofing the entire surface would probably help. The flashing on the right in the fourth image has pulled away from the wall and needs to be adhered back to it; Sikaflex 11FC could be used for this. At the moment, water would be running down the wall and behind the flashing, entering the area of the wall below. Once the roof is waterproofed and the flashing repaired, you'll need to speak with a drainage expert about how to route the roof's overflow to a more appropriate location than directly onto the window beneath. The downpipe right next to it would be a good option.

You could attempt to resolve these issues yourself, but I advise you to have a professional examine them first to get an idea of what needs to be done.

Please let me know if you have any questions.

Mitchell