Does ‘FLASHING” remind you of a ‘perv’ in the park? (Part 2)Connotations of ‘CAULK’ and ‘FLASH’ .

Does ‘FLASHING” remind you of a ‘perv’ in the park?  Does that mean “CAULK” is a 4 letter word to you ?

That’ seems to be the case now a days.


On the left: Roofing meet flashing (black cap flashing). Flashing meet caulk. Caulk meet old tar ( old brittle cracked leaking tar).

On the right: Roofing meet new flashing (couldn’t be made smaller). New flashing meet surface caulking. Surface caulking meet porous wet brick.

SO who’s leaking now : Every place the new caulking touches old materials some small amount of wetting or water entry is happening. It only gets worse over time.

chimney flashing details

The proven standard for flashing  was returned into the wall or chimney material, a mortar joint in the case of masonry. It was then bent downward to generously cover the upward edge of the roofing membrane. That top edge where it tucked into the masonry was filed with caulking from behind the brick face to a bevel finish on the outside that shed water.

This was called ‘let-in flashing’ and it works very well. The core of the caulking in the slot or brick joint takes a long time to dry out, i.e. age. Where it does age the top returned edge of the flashing is still there to redirect any water that has gotten by back out to the surface and away. The better workmen made a small up turn at the inside of the return inset into the brick. Very often this functioned effectively long after the original caulking dried up and washed away.


The job shown in the photo above is not that type.  It is what we call caulking reliant.  That means every thing is sealed with the caulking and has to rely on that bond.  No matter what the caulking manufacturer claims about his product, it is only as effective as the material it is in contact with.

So if you caulk against old tar, etc. your water proofing is as good as…. the old tar.  SO that edge will soon fail.  A handy man sent up with a tube of caulking can try to keep on top of it.  And he can keep things fairly dry, but he has to be a diligent and frequent visitor.

This is what home inspectors mean when they describe something as a maintenance intensive installation.  Is it wrong, or a bad job?  No, but it is short sighted economics that the home owner needs to be aware of.

So is caulking a four letter word?  Maybe, but many caulking jobs are the generators of unrestrained expletives.

And flashing is getting so minimal and ineffective it may disappear from popular lexicons and the only meaning recognized may be that shadowy trench coated figure in the park.




Original blog post on ActiveRain: Link to Blog Post