This house was built in 2000, it was perfectly reasonable to expect jamb flashings (up the sides)


This photos shows the very obvious sill flashing, a Good Thing. I made a cut out to look for the jamb flashing and see how the end of the sill flashing had been formed













no jamb flashing, at all!


Note also the rusting reinforcing steel, not fully embedded in the mix....





A close up of the rusting steel


No sealant between the stucco and the joinery - so it was inevitable that water was going to get in. How could they get away with this in 2000? The house had a CCC.....






This is a different house, built a couple of years earlier in 1998.

Again, a nice sill flashing, again I was wondering, what has been done up the sides?







Much better - a jamb flashing, and even a crude "stop end" on the sill flashing, to stop water going off the end. And the jamb flashing was well sealed to the sill flashing. What more could you want?


Well, I just couldn't see where the water was getting in (the framing under here was rotted out) so I blocked up the weep holes in the joinery and filled it with water dyed red to see if the mitre in the joinery might be leaking...






It wasn't so the stucco was replaced and the weep holes opened and the dyed water flushed out....now here is the interesting part


if you look closely you will see red stained water which was sitting on the sill flashing has soaked right up the side - and that is the point, stucco is highly absorbent, it soaks up water quite amazingly!

So if it can get into the stucco - and here it could via a crack - it will always take the easiest route, and here that was through to the framing.....









another window, another example of water leaking off the end of the sill flashing, soaking in and running down....















A close up to show what happens when it gets to the bottom of the fibrecement backing - no escape, so it soaks into the framing

and rots out the bottom plate


















same thing - can't escape when it gets to the bottom ....



note the water stain on the cut stucco...water soaking out from the soaked and rotting bottom plate














all because they didn't follow the manufacturer's instructions (see below)






Not that difficult, this detail came out in 1996. Clearly shows a nice 6 mm gap at the bottom, so the cladding can drain freely....


A selection of photos of remediation related issues.
Apron flashing ends

Misleading moisture content readings


Stucco is the oldest of the three types of monolithic cladding and the least regulated. The plaster mix is still generally made on site from sand and cement. In Auckland there have been problems with high chloride contents (too much sea salt) causing the reinforcing to rust. It is also quite tricky to cure between coats and frequently problems with the curing lead to cracking and failure of the bond between coats. Then there are the problems with the joinery installation (inadequate flashings) and with the control joints (if any were fitted).

Stucco is a "reservoir" cladding - it is capable of absorbing and holding quite a lot of moisture and this may not necessarily be a bad thing. It really depends on where that moisture finishes up - it needs to be able to escape down and out, rather than being forced back to the vulnerable framing. So where the base of the cladding is buried - as it almost always is with this type of cladding - this frequently leads to problems.

Below is a small selection of photos illustrating each of these common problems:flashings, rusting reinforcing and cracking, delaminating between coats and lack of drainage / soaked cladding.


Top coat not well attached to base coat - simply fell off


Apron flashing ends
Misleading moisture content readings