Joint between brick and clapboard

[Vintage Veloce]

OK, so I admit this isn't about my garage... but you guys are such a a good resource I can't resist.
Our house was built in 1926 and we are having the chimney re-pointed (replacing the exterior mortar between the bricks).
Apparently, the original build just had mortar between the chimney and the redwood siding of the house. At this point the chimney is fully lined, and is setup as a gas fireplace so there is no real fire concern.
The mason suggests just filling this gap back up with mortar. Obviously, that will crack. I'd love to put something flexible between the mortar and the redwood clapboard, but I can't really imagine anything that will work. Here in San Diego, rain isn't much of a problem, and it has been fine for 90 years, so I guess I should just mortar it back up!
But are there any other great ideas?
Maybe, after the mortar is done, some kind of finish trim board, stepped to match the clapboard? I could caulk that to the clapboard siding and the brick. But the brick curves, so that's a problem.

 

[Varty Yo]

Im a bricklayer by trade and id suggest putting foam rope in there then a caulking bead to seal it up. Will allow for expansion and contraction.

 

[PugetDude]

^^+1^^

I'd use foam backer bead and "Big Stretch" caulking.

 

[wrenchguy]

is the brick work pulling away?

 

[Kaizen]

That looks like a big gap. Exactly how wide is it? That much caulk is doomed to fail imo. For the look I’d fill with matching mortar.


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[Vintage Veloce]

Some of the gap is large, some small. In some spots the brick ends are staggered or cut unevenly, so one brick might be 1/4 inch and the next one 1" away from the clapboard wall. So it's hard to imagine backer rod and caulk working well.

(The brick chimney is pulling away from the wall in the center a bit. My laser shows the full length of the chimney to be pretty straight vertically, but there is some bow in the center about half way up the wall. The only real way to fix that would be to tear the chimney down do a new foundation for it and build a new one, so I'm ignoring that issue.)

 

[Radix2]

I'd cut the siding back and put in a trim board thick enough to cover the gap and kill the siding off into that, just like it does at every other window, corner, etc.

Running the siding behind brick looks like ****. Bad masonry, bad siding.

 

[coljar]

Im a bricklayer by trade and id suggest putting foam rope in there then a caulking bead to seal it up. Will allow for expansion and contraction.

This guy's in the trade and probably knows what he's talking about.

 

[gnpenning]

Im a bricklayer by trade and id suggest putting foam rope in there then a caulking bead to seal it up. Will allow for expansion and contraction.

Agreed. You can buy backer rod in different sizes. Buy the 1" or larger and press fit or trim in the narrow areas. Caulking may take a couple passes.

 

[Radix2]

Caulking a 1" eight foot long joint on the side of your house...incredible

Come on guys, the trim is missing to do this job properly, replacing it with a big ole glob of caulk?

No.

Fill it with mortar if anything.

 

[yeldogt]

Traditionally -- that would have been filled with mortar. Filled -- not just thin.

Old grown redwood in a dry climate is not going to rot against mortar ... remember "old school" mortar did not have cement (Portland) -- it was Lime mortar. That's actually the best pointing mortar for old stuff as it does not hold moisture like modern high temp cement products .. nor does it crack like them. Older bricks are not as strong as modern high temp fired bricks.

Under cover in a stable climate -- even regular cement mortar should hold up fine. It's been there for 90 years ?

 

[gnpenning]

Caulking a 1" eight foot long joint on the side of your house...incredible

Come on guys, the trim is missing to do this job properly, replacing it with a big ole glob of caulk?

No.

Please show some examples of the missing trim.

 

[gemniii]

Some of the gap is large, some small. In some spots the brick ends are staggered or cut unevenly, so one brick might be 1/4 inch and the next one 1" away from the clapboard wall. So it's hard to imagine backer rod and caulk working well.
<snip>

I'd probably fill the gap ALMOST with something like "Big Gap Filler" instead of foam backer rod https://www.greatstuff.dupont.com/products/big-gap-filler-foam-sealant.html, and leave it low enough to fill further with a flexible mortar/concrete type patch designed for vertical application.

Something like a Quikrete Vinyl Concrete Patch.

 

[Vintage Veloce]

Thanks for all the ideas guys!
We are going to stuff some rock wool into the gap (foam or other easily melted/burned stuff doesn't seem like a good idea) and fill it with mortar as it was. I may try and add some trim over that in the future, and caulk the edges of the trim, but first I want to see how the mortar looks and holds up.
I'll note that much of the modern mortar we removed was way too hard, we are replacing with a proper soft mortar (type O) which is a little cement but mostly lime and sand (Cement, Lime, Sand: 1:2:9). If we need to chip it out and redo it in the future it should be much easier than this time.

 

[NUTTSGT]

If it were mine, I'd probably try to close the gap with a filler rod and mortar. If any of it opened back up after it was dry, I'd caulk it with something Sika Concrete fix.

I'm not mason but I don't I could hurt it.

 

[yeldogt]

don't stuff anything that holds moisture in the gap - make a drier mix and finish with a wetter that you can smooth over ... it will be fine