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Brick & Tar Removal

July 5, 2013
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I mentioned in a previous post that the masons (tuckpointers) recommended that all of the tar be removed from the tall parapets before they could properly do their work. I also asked them about some shorter parapets that were in the middle of our roof, in the locations where old exterior walls once existed. I thought that these short walls weren’t really necessary and Sue & I both knew that they would only get in the way of future roof deck planning. (And our roofing consultant thought new roofing would be easier without them.) The masons said that it would be cheaper to remove them instead of rebuilding them.

So I set about making another “hole” in the shorter parapet. Well, this time more than a hole – I wanted to remove an entire 8′ length of wall all the way down to the concrete roof deck, mostly so that I could confirm two things: first, that the bricks sit on TOP of the concrete deck, and second that the two concrete decks on each side, one side constructed in 1913 and the other 1923, were fairly even and level with each other. That would make our roofing replacement easier.

I started by removing the terra cotta coping pieces to expose the top layer of bricks.

Short parapet with coping removed

Short parapet with coping removed

Then I fetched my favorite masonry hammer (the pointy one) a small demo tool and small sledge hammer.  Since this was semi-exploratory work, I didn’t want to damage the bricks in case I found some hidden problem or issue and had to rebuild this wall.

I started whacking away but soon found that I didn’t need to work so hard – the mortar was fairly soft and I could stick the hammer in the joints and just pry away the bricks…

Tools ready...

Tools ready…

Soft mortar = easy removal

Soft mortar = easy removal

The first row of bricks lifted off pretty easily and with little mortar on them; there wasn’t much tar on them either since the terra cotta coping covered part of those on the exterior.

I didn’t want to stack the bricks directly on the roof – who knows how long these will be sitting there and I didn’t want their sharp corners to dig holes into the old roof. I found an old board down in our dock that would fit through the hatch, it happened to have a a stepped-back edge to help minimize the board’s corners digging in as well. I also started a pile for mortar – didn’t worry about that digging in since it’s much lighter.

First row pretty easy.

First row pretty easy.

Save & stack for later.

Save & stack for later.

The second row was where I ran into trouble. The bricks along the sides had a 1/2″ thick layer of tar and gunk, and it held them all together. And since it was SOOOO freakin’ hot, (July on a roof) the tar was soft and sticky, so it was like pulling chewing gum apart.

The tar is like a gluey layer of frosting!

The tar is like a gluey layer of frosting!

I’d only been working for a couple hours and it was time to quit; we were going to friend’s house for the 4th, so I packed up for the day.

Two layers removed (photo taken from north side)

Two layers removed (photo taken from north side)

I took the next day off work – after the whole sandblasting debacle of a few weeks ago, I found a contractor to take the tar all off of the tall parapets with their huge sandblasting rig; they were going to start the next day.

They wanted to start early, like 7:00am, but I convinced them our neighbors would probably appreciate a bit later start like 8:00-ish. They pulled up around 8:30 with an air compressor bigger than the neighbor’s CAR!

What a HUGE compressor!

What a HUGE compressor!

We spent about 30 minutes figuring out where to stage everything; the compressor also needed water to keep it cool, so they left it on the sidewalk and I rigged up a garden house connected to a faucet on the second floor and ran it out a window.

They could place the sandblast pot and all the sand just inside the dock, with the air supply hose running from the compressor, and the sand delivery hose (they brought 200′) would go straight up the outside wall up to the roof.

Sand and sandblast pot ready to move into the dock.

Sand and sandblast pot ready to move into the dock.

I reviewed the scope of work with these guys before they blasted anything; there was a bit of confusion because it sounded like they were planning to blast more than we needed. I spoke with the owner on the phone and he agreed that if all the work he quoted wasn’t necessary, we wouldn’t have to pay the whole quote. (Yay, savings!)

So they started at the concrete parapet. (This was the wall that didn’t need to be cleaned right now. I was somewhat interested in seeing what they could do; we may eventually want to clean this so it may be easiest while they’re here.)

They're starting at the southwest corner - which is concrete.

They’re starting at the southwest corner – which is concrete.

He tried a variety of spots; I let him blast for about ten minutes, and then asked him to stop and talk. It looked like they could quickly remove about a third of the layer of tar, the rest was stuck deep inside crevices around exposed aggregates.

You can see the long stream of sand.

You can see the long stream of sand.

Lots of fog - not much removal...

Lots of fog – not much removal…

I told him that with that result, it probably wasn’t worth doing right now; our priority (for both our time and our money) was to get work done that was required for the roofing, and this concrete wall didn’t contribute to that.

So he moved over to the section of tall parapet where the concrete switches to brick.

Starting blasting the BRICK wall now...

Starting blasting the BRICK wall now…

From where I was standing (at my demo parapet from the day before), it looked like things went pretty fast. Also note on the next pic the “home made” head protection – it was just a long-sleeve pullover with just his face sticking out of the neckhole. (You may need to click the photo to enlarge.)

Making quick progress cleaning brick.

Making quick progress cleaning brick.

This took about three minutes to clean!

This took about three minutes to clean!

So within 5 minutes or so he had almost 10′ of brick nearly cleaned of tar. There were blobs of really heavy stuff that they thought it would be easier to remove manually.

Professional sandblasting setup works great!

Professional sandblasting setup works great!

Because of the distance from the roof to the pot to the compressor, it took three guys to do this job. It required the somewhat skilled person at the working end of the hose (the guy in all the pictures), who would yell messages like Stop, More, Less, Go, to a guy at the back of the roof overlooking the alley, who would then yell and relay those messages to a the guy down at the sandpot in the dock.

With these sandblast guys well under way, I could get back to reason I took the day off: finish the demo on the short parapet wall.

I pulled out another brick frosted with tar, and wondered if my chipping off this tar to save the bricks, after they were free from the wall, was the best method. It didn’t seem terribly efficient.

A brick with tar on one face

A brick with tar on one face

So I tried to remove the tar and asphalt from the brick faces BEFORE taking them out of the wall. All the tools I had at the time were some scrapers and the previously mentioned hammers. The scrapers didn’t work; they were too thin or flimsy for the strong tar. So i painstakingly chipped away at the tar face with the flat edge of the masonry hammer.

Pre-chipped tar face before removal.

Pre-chipped tar face before removal.

Didn’t make a whole lot of progress. Took For-EV-er.

I checked in on the sandblaster – he was moving along fairly quickly. He had now jumped over to another section of wall not necessary for our roofing project. He seemed like he was on a mission so I didn’t stop him.

Sandblasting progress...

Sandblasting progress…

Back to my work…

When I got a full row of brick cleaned (relatively) of tar, I removed that row of bricks. It was a bitch knocking off the tar, but it seemed easier than chipping one brick at a time.

I was at a level where I was now starting to see lots of nails or other fasteners embedded in the horizontal mortar joints. These were most likely from many re-roofing jobs where termination bars were hammered into the wall. There was a wide variety of nails.

A square-shank nail hammered into the wall many decades ago.

A square-shank nail hammered into the wall many decades ago.

But I eventually got to a level where there was less tar and more roofing paper or flashing rolled up the wall, and I could use the long-handled scraper to peel back a lot of it.

Scraper used to peel off sheets of tar/paper

Scraper used to peel off sheets of tar/paper

A layer of roof flashing removed.

A layer of roof flashing removed.

The sandblaster dude was now in a far corner of the roof, over where I removed a hole in the wall to check the terra cotta cornice construction.

Sandblaster is covering a lot of ground quickly.

Sandblaster is covering a lot of ground quickly.

He took a short break to cool off, even though it was still morning. (Several shirts and a mask will make you hot.) He came over and was curious about what I was doing so I explained basically everything you’ve read up to this point.

Sandblaster guy (okay his name is Jeff) said I should give up on that pansy way of removing tar and “go git me a bulldog”. Not knowing what that meant; he explained that it’s like a mini-jackhammer, like a hammer drill that doesn’t drill. Then added, “Well it’s a hammer drill but you don’t use the drill setting and then put a chisel in the chuck instead of a drill.”

He offered to call his bossman and have him bring one down that I could borrow; bossman was coming in about an hour. Sounded like a great idea; I was willing to try it. The whole reason he was offering this is because it was the same tool that they’d be using to remove those heavy globs of tar that they couldn’t take off with the sand.

We all broke for an early lunch; the contractor guys all disappeared; I went into the apartment to cool off, change shirts and grab a bite to eat. I was back on the roof within 30 minutes. I’d given Jeff a key to the front door and he appeared within a few minutes, with “Bulldog” in hand.

Jeff opened the Bulldog case and I immediately recognized it as a Bosch hammer drill. I said “Oh, it’s a hammer drill…” He said yeah. Apparently they only call it a Bulldog because that’s the sticker on the tool itself, named by Bosch. I mentioned that I have a Hilti hammer drill so I bet it will work; I recalled a setting that was able to turn off the hammer or the drilling action.

He was just there to drop off the tool; it was then I realized that they’d be working on this job sporadically, a little now, a little later, some the next day, and so on.

Then I went to check my Hilti drill. While it was an excellent HAMMER DRILL, and it had the option to turn off the hammer action and just be a regular drill, it did NOT have the option to turn off the DRILL action and just be a HAMMER (or chisel).    Damn.

I would need to use their loaner “Bulldog” then, so I ran out to get a chisel bit because I didn’t want to wear down theirs; it was only fifteen bucks.

But hell! Did it make a difference!

The "Bulldog" hammer chisel kicks butt!

The “Bulldog” hammer chisel kicks butt!

Compared to my little hammer and scraper, the hammer chisel chewed through tar & paper like it had teeth instead of gums! I had another layer of tar & paper loose in minutes. Beneath it can be seen an old termination bar, an odd choice of wood. Now it was evident why the old roofing & flashing turned up the brick so high – older roof layers were left in place, and new ones had to go ABOVE the last one. No one ever thought it was necessary to tear off older roofs. Idiots.

An old termination bar made of wood.

An old termination bar made of wood.

I used the chisel sideways along the face of the brick wall. There were two types of goo – the pitch, which would chip off easily, and the tar or roof cement, which was lot stickier. The pitch was a bit harder to remove because it took more control from me to keep the tool in place, but also I had to push enough to trigger the hammering mechanism. As soon as the hammer enacted, the pitch flew off in small pieces, which then the tool wanted to bounce off of the wall because of the hammer action. And I had to keep the tool at a low angle against the wall, or the chisel bit would jam into a vertical brick joint and stop. With the stickier tar, it literally grabbed and held the chisel, which meant a lot less controlling on my part, but I had to push a lot harder to keep the chisel driving through it.

But you know what? Scraping pitch OR tar in ANY way off of a brick wall on a roof in the middle of a hot sunny day in July… always sucks!

Tar removed from bricks with hammer chisel

Tar removed from bricks with hammer chisel

Section of bricks cleared of tar

Section of bricks cleared of tar

Now that the roofing is peeled back from the brick wall, I had to figure out a way to cut it away from the roof deck so I could remove it. If I just pulled on it, it just lifted up a lot of roofing and ripped in jagged edges.

I wondered if the new wonder Bulldog tool could help.

Bulldog cutting through layers of roofing

Bulldog cutting through layers of roofing

Well it sortof worked – the chisel went through and down easily, but the roofing asphalt held onto the bit when I tried to pull it out. It didn’t help that it was hot & soft either. And unlike pulling a drill bit out of wood or metal, having this tool on did nothing to help. The best method I found was to just step down hard with my boot on the roofing right next to the bit and pull up hard on the chisel.

Cutting 1-1/2″ at a time seemed a little tedious but it really only took about 10 minutes to cut a line in front of the demo section. With that cut made and the vertical stuff free from the brick, I could lift out hunks of roofing and flashing.

A good hunk of material removed

A good hunk of material removed

As I progressed down this south face of the parapet, I figured out that if I made some vertical cuts (with the hammer chisel) through the layers stuck to the brick parapet BEFORE peeling it away, it lifted out much easier since it wasn’t still connected anywhere. Once the cuts were made and I ran the chisel down the face of the brick, I could use the long handled scraper and just “pop out” this crap in short sections, and carry them away.

After proper cuts through roofing, it now pops out in big messy chunks.

After proper cuts through roofing, it now pops out in big messy chunks.

Finally I had a good method; make cuts in roofing, chisel away at back against the brick, pop out 3′ chunks. Within 15 minutes I had the whole south face of my demo section cleared of tar and roofing. As discovered in my earlier “roof holes” investigation, there was a thick wet layer of old insulation that I dug out (and can be seen in front of the wall). It was smelly – just like everywhere else I’ve found it.

Demo parapet cleared of tar - and wet insulation dug out from roof.

Demo parapet cleared of tar – and wet insulation dug out from roof.

Now to tackle the NORTH side of this parapet. I started with cutting through the flat layers… but something seemed wrong…

Bulldog chisel goes down WAAAAY too far...

Bulldog chisel goes down WAAAAY too far…

Not sure what just happened but I should have hit concrete and didn’t feel it. I made a few more cuts in case it was just a fluke, like maybe an old hole in the roof or something. But no, I never hit any concrete along this area.

I lifted off what layers of roofing I could and exposed some old gravel.

Different conditions on north side; concrete cant and deep fill.

Different conditions on north side; concrete cant and deep fill.

There was also a concrete “cant” on this side of the parapet. A cant, in construction, is meant as a transition strip where walls and roofs meet to keep roofing materials from making 90° bends, which helps minimize cracking. By having the cant, the roofing makes two 45° bends instead. What was puzzling was that this concrete cant appeared to be installed AFTER original construction and on top of some older roofing layers. Like someone decided later that a cant should be installed. And why concrete? I dunno. Just another puzzle at BAB.

I got a small scraper/chisel tool and started digging down into the loose material. The top inch was gravel, and then some cracked paper layers, and then several inches of loose granular fill. (Almost like vermiculite; but a little denser.)

And it was soaking wet!

Digging deep through the granular fill.

Digging deep through the granular fill.

I tried to dig down to see the bottom of the hole I was making. I could feel the tool hitting a hard deck but I could never see the surface, because the hole kept filling with dark murky water!

It's like a mini-well on the roof!

It’s like a mini-well on the roof!

Time for a break to figure out what’s going on.
(Hum the Jeopardy theme, like time is passing…)

Okay – here’s the deal. Where this parapet turns a corner was the original back corner of BAB when it was a puppy. It was also the location of a back stairwell. While the stair was originally constructed in this area between the first and second floors, (later removed), it was only PLANNED for future expansion through the roof to be later a third floor.

Southwestern Bell always planned their buildings for expansion – both vertically and horizontally. You can see this in other Bell buildings, most notably in the one still in use in mid-town St. Louis, across from the Contemporary Art Museum.

An old 2-story Bell building with 3 floors added on top of it.

An old 2-story Bell building with 3 floors added on top of it.

And when they PLANNED for a future stairwell, they designed the construction to be easiest to remove in the future. One piece of evidence showing what they did was to place additional structural beams around what will be the future stair opening, so that they don’t have to build that later when the hole is cut. The other thing they did was to make the concrete slab thinner where it was going to be removed. A thicker slab is needed when you plan to place people and equipment on it (i.e. the current roof when it is the third floor) but when all you need is a slab for roof to hold water and snow, (i.e. where there will be a stair opening), it can be thinner. A thinner slab will be easier to cut out later.

So here’s the problem – instead of making the TOPS of these two different thickness slabs even, they constructed it with their BOTTOMS flush. (I confirmed this just by going to the second floor and looking up at the roof.) This essentially made a depressed slab in this part of the roof. All of the granular fill on top of it was intended to keep the roofing material at a similar level as the rest of the roof. Of course no one expected the roof to be leaky, and now that it IS leaky, this depressed section is basically a bathtub, retaining water with no place to go. So there’s been YEARS passing letting this water develop a nice dark tea color and special dank smell.

Enough history; back to the brick demo…

The mortar joints are still not so great – I can pull apart rows of brick with the pointy end of the mason hammer. This is good confirmation in a way, in that it is probably going to be a good decision to take down this parapet.

Soft joints are not good for brick walls you want to keep. But good for easy demo.

Soft joints are not good for brick walls you want to keep. But good for easy demo.

A couple more puzzling finds. A few bricks had what looked like black charcoal-y mortar. It was very light and crumbly. No idea what this was and why there was only a little bit of it. There was also a layer of papery flashing turned under a row of bricks, just above the concrete cant. It was full of holes (not by me) so it didn’t work very well.

Brick with blackish "mortar"?

Brick with blackish “mortar”?

Deteriorated flashing...

Deteriorated flashing…

There were some bricks with better joints that needed a little coercion; I mentioned at the beginning that I had a hammer and a small demo bar – but now I have a Bulldog available! So I used the hammer chisel on the bottom couple layers of bricks. I tried it on the concrete cant too – but no good; I’ll have to find a better way to remove that.

I think this is the last row.

I think this is the last row.

There were a lot of mortar chunks all over so I couldn’t clearly see if it was concrete deck below this parapet. So I swept up the debris to get a good look.

Finally - the concrete deck exposed! Plus a little black well.

Finally – the concrete deck exposed! Plus a little black well.

Fortunately the newer 1923 concrete deck was poured first before the parapet was built. (Yes that’s a whole ‘nuther puzzle as to why it was rebuilt…) This will make the new roofing easier. What I DIDN’T learn in this investigation is whether or not the original 1913/1914 deck is the same level, because the spot I exposed was a depressed area to begin with.

It was starting to get dark, so I quit without removing ALL of the lower bricks; before cleaning everything up I took one more photo.

Stand back and enjoy the destruction.

Stand back and enjoy the destruction.

This is just the beginning; it looks like I’ve got a lot of hot days on the roof in my future…

One Comment leave one →
  1. September 1, 2013 1:01 pm

    Wowee! This all looks amazing. I am sorry I didn’t know you had a blog about the building, but now I can follow along. Don Occhi, bless his heart, linked to you. Thanks for taking the time to photo and describe! Susan Wiegand

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