Fenestration leaks, quite common. Techniques used in building them are important esp where it sits. If there's no step down edge, unless a high quality waterproof sealant is applied on the outside, the water will eventually seep in on account of the weathering from the heat of the sun.

Admittedly, even my previous and current condo has been plagued by this issue. All I have researched is that it all boils down to how construction methods conform to correct building science where windows and walls join are concerned.

Seepage resistant construction and installation site preparation with proper sealing materials are crucial in that order. If the design is flawed, no amount of sealing will prevent seepage.

If there's any contact of anyone who can help reconstruct the windows and implement these but I don't know how much it costs. See here for sealants and joint site sealing material and page 20 onwards here on common joint site failures.

This post has been edited by halcyon27: Jun 27 2017, 06:35 PM

That's assuming the window anchoring point design is seepage resistant which is unknowable since neither he nor you witness it during construction. Seepage due to mismatch of sealant is the current symptom combined with a seepage path as obviously seen inside.

If building management have the construction details for the windows by the original installer, perhaps an experienced window installer that specialises in weathering issues could scrutinise if it's ok or there's a design flaw against wind driven intrusion and take a best shot approach to remediate but even that does not guarantee anything. It takes a lot of know how to make a tight building envelope and windows is a common place where this issue occur. At least with dry area balcony doors, weather strips can easily DIYed by home owner.

The only way to ensure it's reliable is to have it rebuild but that assumes management will allow due to high winds and the risk of things like furniture and people being sucked out.

Assuming the most probable outcome, it will be a gamble. Acrylic is not a good choice for sealing due to weathering altering it's elastic properties over time ie cracking. It may not endure our weather pattern. See the Sika pdf URL I attached above in my earlier reply.

This post has been edited by halcyon27: Jun 28 2017, 06:04 PM

He could be right. Silicone is likely used where weathering is avoided. The type suited is elastomeric sealant as described here and a good example is Sikaflex.

This post has been edited by halcyon27: Jul 3 2017, 08:42 AM

My take is it's a combination of "both and" rather than "either or". Waterproofing cement is to prevent seepages into the walls and forms the foundational layer even before the window frame is installed. Sealant is on the joints and flashing where it meets the wall etc.

Sealant has many types depending on application. Use the correct one is where it counts.

Waterproofing cement is probably like a waterproof primer coat and works best even before window frame is laid.

Like I mentioned before, a seepage resistant design helps which makes the application of cement coat and sealant effective due to a layered protection approach.

This post has been edited by halcyon27: Jul 3 2017, 10:49 AM

Google "fenestration caulk sealant" and read up a bit then compare the types available. Here's one example.

This post has been edited by halcyon27: Jul 3 2017, 08:46 PM

Go back to your pictures again and verify if the frame sits lowers than the outside. Mine was like that. Hence eventually after even a year or two the leaks came back. Installation defect from day one. West facing facade experience the harshest sun. Hence the weathering rate is accelerated. Read up first based on what I shared esp the pdf. You can decide the best course of action from there. But expect periodic maintenance as this is something that won't go away even in well designed ones, sealants/caulk eventually have to be stripped and reapplied.

This post has been edited by halcyon27: Jul 5 2017, 05:21 PM

Reviewing the pictures, one of them being a full height fixed glass, that one seems to be. Anyhow, get more varied opinion first and resist the temptation to fix it fast. What I've experienced as well as learnt from others sharing is that the leaks more often than not, never happen at the spot of occurrence. They originate elsewhere. This is common with roof leakages that is seen dribbling down the walls rather than from a misaligned tile or a cracked one which is easy to spot. And they come back during a heavy downpour even though it was 'fixed'.

Consult a facade specialist as to what type of product they use to weather seal. Not the brand but the type based on chemical composition or silicone, acrylic, PU, hybrid, etc. Which can stand UV, which can be painted over, which one can flex with movement from wind or pressure and still retain its shape without leakage, resistant to common failure at the joints due to sagging under its own weight or changing chemical composition that varies it's sealing performance.

The best way is to simulate a rain and diagnose. Probing with a slightly pressurised hose (not too strong but those with a twist adjusted pressure nozzle used in the garden or washing up on the yard) in situ should be able to reveal since not all the time we catch the leak during the rain. This is way more accurate since one can control the test and observe the results.

This post has been edited by halcyon27: Jul 6 2017, 09:08 AM

Btw, this sealant being neutral cure is excellent for kitchen and bathroom esp sealing the joint and gap around stainless steel sinks.

This post has been edited by halcyon27: Jul 6 2017, 01:47 PM

PU. It expands then they cut out excess and apply cement to seal I suppose.

The thing is by right proper window installation would have resolved this using a combination of water seal membrane (mostly EPDM type), raised "I joint" profile where windows is installed. Window frame sits on the "I joint" profile with the membrane touching the external side of the I (faces out). There could be sealant applied to make it water tight esp where the membrane on all corners meet and also between membrane and I joint. A cementitious filler is applied into the remaining gap before general cement screed. The other end pieces are added with the appropriate weather durable sealant and flash joint pieces of any are added or a weather seal paint coat is applied before painting over. Bottom part must be able to drain and is sloped.

The skill of the installer is crucial otherwise it is as good as not having these things. Also is the window frame becomes disjointed during installation or after years of operation and if the outer sealant in contact with it is insufficient to accommodate the stretch caused by it, a leakage path is introduced.

After hearing all this and reading it from the window installation and leakage specialist what with all that possible failures caused by sealant failures (contributed by anything from age to joint failure due to weathering and movement), you can surmise this will be an ongoing issue.