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“Hole in the wall…”

April 2, 2013
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Before we can replace the leaky roof, we need to tuckpoint and repair the parapet wall. Before that, we needed to confirm the structural integrity of the complex terracotta assembly of the top of the wall. So some expert consulting was required…

But first, here’s the “pretty” side of the parapet wall – as seen from the street:

Terracotta of parapet wall.

Terracotta of parapet wall.

It looks pretty good for being 100 years old.

Though the roof side has some ugly history — for years and years, previous owners of BAB felt that the way you kept water out from under your roof was to slop globs of tar and other roofing material all over the brick wall instead of properly repairing the masonry. Not the best long term solution, as you can see in the next picture that most of the black mastic has peeled off, allowing rain & snow to get into the mortar joints.

Oh yeah of course there’s the “reflecting pond” too.

The "ugly" side of the parapet wall...

The “ugly” side of the parapet wall… picture taken Easter Sunday.

(Funny – not many people have been up on the roof – we always invite guests but they rarely take us up on it; maybe it’s the fact you have to climb a ship’s ladder and crawl through a hatch… plus you might spill your glass of wine…)

You’d have to zoom in a few times on that last photograph to see it, but almost halfway up the wall are several rows of brick whose mortar joints are quite blown out. Some previous joint repairs are evident, though based on the black cover-up goo everywhere, those repairs are quite old.

So I met our structural engineer Ron up on the roof about a week ago. We looked everything over; told him my thoughts & concerns about the gaps in the joints, and in  particular the visible edge of some piece of steel embedded in the wall where mortar had completely fallen out. The steel has gotten all rusty and flaky. Potentially really BAAAAAAD.

After an hour or so of sketching, observing, poking and picking (at the wall of course) Ron suggested that the wall in general is in pretty good shape, even though it doesn’t look so good on one side.

I gave him an idea of how the wall is assembled, though my thoughts on that are based on a very vague outline of the terracotta that shows up in only one of the drawings we have from the 1928 expansion.

I’ve copied a portion of that blueprint here and highlighted a section through the parapet wall in a light orange color…

This is the only place the parapet appears in our old drawings.

This is the only place the parapet appears in our old drawings.

Ron thought the expansion and opening of several horizontal joints was due to water getting to that  steel by neglect of repairing the mortar joints, rusting the steel, and making it expand. (As opposed to my grim idea that the entire wall was leaning outward ready to fall below!) He said that steel, when rusting and flaking, can expand up to ten times its original thickness, and if embedded in a wall like this, it was bound to push out some bricks and joints.

The main reason I asked Ron to review the wall was to give us some specific recommendations on how masons should proceed to repair the wall. While sometimes you can get that information from a contractor themselves, in a bidding situation where you’re asking several companies to give you an estimate for work, each one may recommend a process or solution that meets their needs (and possibly profit) better than yours. By getting our engineer’s recommendation, we can request each bidder to provide a cost for OUR solution instead of their own.

So Ron thought that the first layer of brick in that horizontal band could be removed in 3′ or 4′ wide vertical swaths without structurally weakening the wall and causing the parapet to crash below. (Note that it’s ME that keeps tagging on “the WALL is falling!” and not Ron…)  Then the bricks removed can be rebuilt with fresh mortar and the areas above and below can be repaired with normal tuckpointing methods. (NOT involving whole brick removal.)

I felt pretty good about this direction, and he assured me the wall isn’t falling. Though he DID recommend that I take out a section of bricks to verify the interior condition of the wall, and try to see what that piece of steel was and what role it played in the entire assembly.

I showed him a section of the wall that had a big open joint that would be a good exploratory area; I liked it because it was adjacent to an adjoining wall that would help keep the wall from falling to the ground. (There I go again!)

Good place to start - see that big open joint?

Good place to start – see that big open joint?

Ron left, and offered that he would be glad to review anything I find out after I open the hole in the wall, even said he could come back if needed. I wonder if he knows how to tuckpoint?

Unfortunately, the next day it snowed like crazy, producing the recent photo by Sue. A waiting game for warmth and dryness ensued.

It wasn’t until Easter weekend that schedules & weather aligned and I could get on the roof with some tools. So I loaded a tool bag with some masonry chisels, a small sledge hammer and my favorite rock hammer; tied a rope to the bag and hoisted it to the roof.

Starting in that wall section of the last photo, I quickly popped out two bricks. I was surprised that the back of the big terracotta sections were right there, visible to the world. Hidden for a hundred years, now exposed.

The tops of terracotta pieces are visible now.

The tops of terracotta pieces are visible now.

Look close (click on pics to zoom) and you can see that piece of flaky steel a lot better. While it was a better view of the edge of the steel, I needed to go further and try to see it from the top and the back – I needed to know if it was an angle, a tee, I-shape, etc. So more bricks needed to come out

For a brick wall seemingly to be coming apart, the next two bricks were a pain the ass to remove. The mortar was really sticking together and I had to chip it out in little pencil-eraser sized bits. But I got them out. (I was a little afraid to just wail on the wall with the hammer – too many vibrations into the whole wall could make it… dare I say… loosen and fall to the ground?

Two more bricks removed...

Two more bricks removed…

The edge of steel is now a lot more visible. Some parts of it would just disintegrate with a tap of the hammer. Those parts were staying in place because of rust.

The next photo shows a zoom in up really close – you can see that the thickness of the steel is “bloated” from the years of rust and flaking.

Hidden steel is now more exposed.

Hidden steel is now more exposed.

While I was now officially at Ron’s “you can safely remove ONE layer of brick” directive with this wall, I wanted to go deeper so I can see more of this piece of steel.

So I rock-hammered on the thick blobs of mortar just above the steel. You can listen to the sound of the hammer taps and you can tell when pieces are loosening. When it sounded dull and thunky, I could wriggle the piece loose and I held it in my hand.

Odd piece of diagonal brace, now rusted.

Odd piece of diagonal brace, now rusted.

Interesting… this hunk of mortar was holding onto a slim rod of steel, now rusted through, that connected between the legs of the angle. (ASSUMED to be an angle at that time.) The only purpose I can think of is to provide additional embedment for the mortar added. Hmmmm… Set that aside for now.

I kept digging around the steel – I needed to know if this was truly just an angle, or perhaps a tee shape, or even an I-beam shape. By digging and poking underneath and top, I was able to confirm that indeed it was just an angle, approximately 2″x2″ with some occasional diagonal wire bracing,

Close-up of rusty steel...

Close-up of rusty steel…

I pulled out three more bricks from the next row up; with these gone I could now access the top of the steel flange and poke around the back side. (Of course if there was not so much water/freeze damage, I would not have been able to slip a fingernail file back there. But my finger could fit behind the steel; and the absence of another leg projecting out the back side away form me, gave me confirmation that this steel was as simple angle and not a tee shape.

The new hole in the wall.

The new hole in the wall.

Now with this investigatory step done, we’re ready to bring in the masonry bidders! They’ll be able to see inside the wall they’re getting into, and should not have any surprises…

Funny, Ron casually suggested that I could do all of the tuckpointing. I chuckled – last time I did tuckpointing was on our little cottage in University City several years ago when we the purchaser had requested some repair… I swore it would be the last. But I guess I should wait and see how our estimates come in…

Tuckpointing at the old cottage

Tuckpointing at the old cottage

5 Comments leave one →
  1. Stephen permalink
    April 6, 2013 5:55 pm

    Wow! That rusty steel looks like quite a nasty complication. Hope the parapet tuckpointing goes well!
    The flat roof on my little one storey brick bungalow is not nearly as big as yours. I had the roof replaced several years ago. The roofing material curves up from the flat roof all the way up the parapet, so the inside of the parapet wall is completely covered. When they took the old roofing off and revealed the bricks, not only had no tuckpoing repairs been made, but there was NO mortar between the bricks. Apparently when the roof had been repaired in the past, instead of tuckpointing, they just stacked the bricks back up without any mortar at all and roofed right over them. Gee, now I know why there were so many leaks in my ceilings on the outside walls of the house.
    It may not be much consolation, as you have so much more wall than I do, but it could be worse. At least you have some mortar between your bricks.
    Stephen

  2. April 2, 2013 7:04 pm

    Good job, buddy.

  3. April 2, 2013 6:54 pm

    Interesting investigation. Better you than me!!!

  4. Sue permalink
    April 2, 2013 3:55 pm

    Where was the spider nest?

    • Tom permalink
      April 2, 2013 4:20 pm

      Not sure of the species that made it, but look at the third from the last photo in the post; in the upper right portion is web or coccoon-like remains…

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