The roof - Earthquake - Lessons Learned

Roofs in Panama are relatively uncomplicated. There's a roster of cariolas and a layer of sheetmetal on top of it, affixed with screws. All of it rests on some columns.

My roof is just like that.

Sounds simple, right? Yeap. And in theory, there's no difference between theory and practice. But, as you know, in practice there is! (Yogi Bera )

So, the theory is, I have 4 columns on the terrace, 2 rows of each 4 columns ontop of the walls of the rooms, and the corners of the bathroom which carry the trusses. Since I have a teak plantation and love wood, I decided to use tree trunks as columns. When the trusses are installed and the cross bars welded on, the whole structure is very stable.

Here' comes the practical part:

To assemble the whole thing, these columns need something to keep the vertical! They rest on a metal boot which is concreted in into pedestal on the terrace or wall. But it's the same problem as trying to standup a pencil... 

Yesterday there was an earthquake just about 70 km away; 6.6 on Richter scale. It was quite noticeable! My glassjar actually fell off the shelf and broke, that's how strong I felt it here! 

It's a bit scary, but if you're standing on the ground and don't have a large building or structure atop of you, it's not really a problem.

What it did do, though, was, to remind me, I need to keep earthquakes in mind with my house! I have everything build on a solid concrete slab, which rests on a thick layer of crushed rocks. So if something moves about the house, the whole house is moving. I am hoping it won't develop cracks from tensions created by traditional foundations shifting in relation to each other. So that is "bien"!

But, looking at the structure from the distance, it dawned on me, that the columns that hold up the roof need to be supported in a way, that even if the house starts moving sideways, they won't loose their balance.

Being spiritual as I am, I see this earthquake as sent by the Universe to help me make the next step!

As I am thinking about how to reinforce the columns, I realize, that this is actually the solution for the problem of how to install the roof trusses one by one and keep the columns vertical while doing so!

So, today, I added, where visible, cross boards criss crossing the space between two columns on top of the walls; and where not visible later, 1/2" rebar criss crossing the columns of one row with the respective other of the next row. With that, I have 2 groups of four columns which are interlocked and stabilized amongst each other. 

That allows me to lift the heavy center beam in place, and weld it onto the little pieces of cariolas I used on top of the columns. And later, I can lift the trusses in place, too, and have the columns not just sustain vertical force of the weight, but also horizontal force of the trusses shifting and moving during installation.

Another item of practice vs theory:

The central beam consists of 6 pieces de 15cm by 610cm cariolas, calibre 16 (the strong one). Each of them weights (estimated) 40 to 45 kg (80 to 90 lb). The whole thing is 18 m long and weighs somewhere between 240 to 270 kg!

[one of the trusses - a “cavallo” built of two sandwiched cariolas]

It needs several strong men to lift that thing! And, until it is welded in place, and supported by welded-on trusses left and right, these men need to hold it in place. 

My original design did not have this center beam, but only 4 individual trusses, running in parallel. The architect added this piece. Also, my design had the roof be symmetrical, so both sides the same area, and the same inclination. 

That centerbeam, of course, needs to be supported, so the architect put it ontop of one row of columns - he chose the columns on top of the corners of the wall. Now the roof above the terrace is about 5 meters wide, and the side above the rooms is 7 meters.

Really, that center-beam carries no weight whatsoever. It did not need to be so strong! Instead of using ultra strong and heavy 15cm wide cariolas, 7.5cm wide ones would have sufficed! And I think we wouldn't even have needed to make a "cavallo" - that is double the U-shaped cariolas to make a tube shaped beam.

But, we have the thing already, so we might as well use it...

However, how to put it in place?!? If we put it ontop of the columns on the corners, all the strong men are standing on one side of that heavy thing. If it ever shifts too far to the other side, we won't be able to hold it, and it will fall to the ground - who knows what kind of damage this might cause. And the one or other men might fall with that thing off the ceiling of the room as well!

So, today, I came up with the idea of flipping the roofside around - i.e. have the terrace roof be the 7m wide one, and the roof above the rooms the 5 meter wide one. That allows us to put that centerbeam ontop of the column that in the center of the wall of the room, rather the corner. With that, men can stand on either side of it when it is being put in place!

Today, I was able to install one and a half of those 2 4-columns groups. Yeay!

I did not have enough teak logs for all the columns. So I thought of using some other logs. Unfortunately, ants got into one of them. It would be very difficult to replace such a column once the roof is in place. So I don't want to risk just to kill the ants and install anyhow. Instead, I contacted the sawmill and asked for another log. It's cedar or oak or teca - I will see once he delivers it, hopefully tomorrow...

Once I have this log, I can finish the second group of 4-columns. And once that is done, we can install that darn center-beam. And after that, we can install the roof trusses of at least on side of the roof. For the other side, I need to install and reinforce the long posts on top of the pedestals on the terrace. That's another hot topic, for which I am not yet sure I have a solution that will work in practice... 

Well, tomorrow is another day... We'll see what I'll learn today, and what ideas I'll be given by the Universe tonight...

The roof - day 6 - Sunday

On Sunday, Sergio came over for another 1/2 hour to add a few more missing screws to ensure all sheets are securely fasten onto the cariola structure. Originally, we had planned on installing the caballette - the sheet-metal that is put on top of the roof, right above the main cavallo, just where the sheet metals of the east and west side meet.

However, After he ensured me that not installing it will not cause much water leakage, I decided to postpone this task until we come back from Santa Catalina in 2 to 3 weeks...

More than 88 screw heads need to be covered by sealer paint - it gets mighty hot in the sun ontop of that roof!

I spent the Sunday morning on top of the roof, covering all 800 screws with Sulfatil ( a thick paint-like liquid that serves as sealer) to ensure none of the screw holes. It took almost a hole quart. Well, I'm telling you: It gets mighty hot on the roof in the sun - even though we're 700 m (2200 ft) above sealevel!

 

Oh, why did I postpone the installation of the caballette?

Well, I noticed that even thought the sun is heating uo the roof quite a bit, and in the sun it is quite hot, under the roof it is very comfortable. Not too hot, not too cold. I'm guessing this is, because the hot air that develops right below the burning hot zinc, is rising up to the highest point of the roof, and, as there is no top yet, escaping freely to the outside. I'm guessing, once the caballette is in place, the air will no longer leave so easily, and it will get a bit hotter. When I mentioned my concern to Sergio he confirmed: once the caballette is in place, it won't be so nice and cool anymore on the terrace!

Last night I had another one of these great ideas...

If, instead of screwing the caballette directly onto the zinc, I screw pieces of cariola onto the zinc, and the caballette ontop of these cariola pieces, there will be holes, through which the hot air can escape. And, since the caballette is 60cm (2ft) wide, the overhang of the caballette over the zinc will still be wide enough in relation of the 7 or 10 cm height of the cariolas, that rain won't be able to enter.

To do this, however, it requires to cut about 40 pieces of cariolas, and drill 2 or 3 holes into each of them to attach them onto the zinc. That takes time. And one person on a Sunday morning is not going to be able to accomplish this...

So, I'm hoping the gap on top is not going to cause too much problems, and we'll be able to do the right thing when we get back here...

And, I guess, I'll be adding another "The roof - day X" post by then...

The roof - day 5

So, yesterday we ended the day with the roof almost finished. 20cm short, due to the new zinc being narrower than the original, and 4 2.1m pieces missing to complete the last four runs. I was really frustrated and pissed.

But, like so many times before, over night I got an idea! First thing in this morning I measured the second set of sheets, the ones that didn't work for the original ones, which forced me to cut those beautiful long sheets into pieces to make up for the missing 2 m on top! Ha! Turns out, their canals are 31 cm! Yeay! They didn't fit the original zinc, but they do fit the new long sheets!

Roof almost finished - Weibi, the dog who adopted me last year when I arrived, and two of the five puppies she graced me with in December, are enjoying the cool evening and sunset

And, to compensate for the missing 20cm overall roof width, I had one of these sheets of the second set cut in half lengthwise, making 2 pieces of 4.2 m. Using these as second to last run - with a little more overlap as usual - and then finishing up the roof by using the 4th new long sheet with one more of the 2.1 m long sheets of the second order.

Phew! What a juggling!!!

Finally, the installation of the missing two pieces of facia on either side of the west-slope of the roof, made the day complete!

The roof is finished! 

Well, almost...

The roof - day 4

Yesterday, the east side of the roof was completed, and the west side got 14 of 18 runs, too. Now. the house looked like a house already. It was possible to get a feel for the terrace, and the rooms, and bathrooms. 

It felt AWESOME!!!

Looking at guest room from terrace, part of the kitchen area on the left

Looking at master bedroom from terrace, other part of the kitchen on the right

Much of the roof already in place. Guest room in the foreground,master bedroom in the back-ground, and large terrace in front of them

Terrace and view as seen from the kitchen

I had ordered the missing zinc (the local name for roofing sheet metal), and had it delivered yesterday. So we're all set to finish the roof today! Yeay!

So I thought!

Turns out, the 5.5 m long pieces were from a different manufacturer than the 4.2m long pieces. And, these manufacturers use a different canal width! Sounds familiar? Well, yes! But, originally, the problem was - so I thought - that I had bought the zinc form different ferreterias at different times. This time, I made sure I bought them at the same time form the same ferreteria!

Still, they had given me incompatible zinc!!!

5 canals 30.5 cm

5 canals 31 cm

another one with 5 canals 31 cm

5 canals 30 cm

I was really pissed! Not just is that stuff quite expensive! But I now have a whole crew of workers here, that can not continue with their work - but still want to be paid for the day!

I climbed onto the roof and started measuring the canal0-widths: original ones: 30cm for 5 canals. New long ones 31cm, new shorts 30.5cm! Darn!!! Aside of that, the new long sheets are a few cm less wide than the original ones. So, the last 4 runs come out about 20 cm to short for where the roof should end!!!

After some lamenting and - yes I admit - cursing, they day finished with 4 runs missing the top 2.1m, and the zinc ending 20 short of the end of the roof!

Well, almost! 

The roof - day 2

Well, to connect with the last post: I did get an idea for the four big columns.

 Instead of individual small peaces of cariolas, I connected three full 3" cariolas  to make one long piece.  Then, we were able to place this long piece onto all four columns, while they are still on the ground.With four strong men, and a fifth one ready with the welding machine, we then lifted the four colmns in place. The welder connected a rebar crossing from column A that we just lifted, with column B on top of the wall, and the large column B with the little column A on top of the wall. This criss-crossing of rebars held the columns quite stable in place.

In the next step, two guys lifted the truss on top of the three columns and welded it all together. Then repeated the same for the other three trusses.

With all the trusses in place, we lifted the prepared 18m (60ft) long, 1.2m (4 ft) wide 6-fold H of 4" cariolas in place, secured them with straps, ensured there was the same overhang on both sides, and welded them in place. 

The final stop to finish the structure, which will hold the sheet-metal, was then really simple. Just weld the 18m long 4" cariolas at a distance of about 1m from each other form the top to the bottom.

After the 6-fold H was in place, the masons returned to putting plaster onto the walls, and the second roofing crew went back to the other side of the roof, adding more sheetmetal onto the structure that was completed yesterday.

By the time the evening of day 2 came, the eastern half of the roof had 5 of the 18 sheet metals installed! Yeay! And the western half of the structure was completed as well.

A very productive day! And the part that I was most concerned about - aside of installing the main cavallo - was taken care of, and turned out to be relatively easy!

Public Transportation

 Panama has an impressive public transportation network.

Panama City has two subway lines, that connect the national bus terminal to the center of town, and all the way to the airport. Well, as of now: almost the airport. You have to switch to a bus for the last 2 km. However, they have been building the extension to the airport over the last few years - interrupted by the pandemic as so much else in the world over the last 3 years - but now they are almost ready, it looks.

They are also building a third line, which should extend westward to about 20 or 30 km outside of the city. Every time I pass the construction site I am asking myself: How come Panama City can do that, and Atlanta is incapable of putting in more rail - even though Atlanta is criss-crossed by old rail lines, which could easily be used! The answer, of course, is obvious: Atlantans and Georgians - like most of the US population - doesn't care about public transportation. They prefer to be stuck in traffic, cursing out everybody else who's on the road blocking their ability to go where they want to go... But, let me get off my soapbox...

The Panama Metro is teaching their clients about proper behavior while being on the subway and the stations. I find they are doing this in a lovely way:

Aside of the subway, there are many buses (200 or so) that take people anywhere within the city and suburbs. The cost is also quite amazing: $0.25 for a bus ride, and $0.35 to $1.35!

What I would love to see is a train line from Panama City all the way to Paso Canoas at the border to Costa Rica. When that would be there, I'm sure the Costa Ricans would build their own line from San Jose to Paso Canoas - can't be that the poorer neighbor has a train and Costa Rica does not! 

I heard, that the Chinese offered to build that train, but the Panamanian government declined. Smart folks! I'm pretty sure, though, if the EU would offer the same thing, they would thankfully accept. 

Even outside of the city, all the way to the most remote village, there's public transportation! The National Bus Terminal is quite impressive. Although confusing for a foreigner, who doesn't speak Spanish. After trying it a few times, though, it becomes quite easy and convenient.

You can get to any location within the country, where there are enough passengers to fill large buses. To the smaller villages, you simply switch bus at the next closest larger town.

I took the bus from Bugaba in Chiriqui to Panama City. It took close to 9 hours! The bus made a stop half way in Santiago Veraguas, where everybody got off to used the bathroom and/or grab a bite to eat at the restaurant at the terminal. The cost for this trip? Whooping $15.65!!!

Taking the bus from Salzburg City to my old hometown of Tamsweg, only 2 hours away, costs Euro 18.70.  A train from NYC to Trenton NJ, also about a 2 hour trip, costs $ 21.00.

The Walls

 Once the slab was pored, and had rested over the weekend, we started laying the blocks.

It is very different from in Austria. There the complete walls are made of blocks. Here, however, the building code requires that corners, door- and window-jambs are pored concrete, and not just blocks. Looking at the worst practices block-layers are using here in terms of filling the holes, the small size of them (just 10 cm thick), and the quality range of blocks - from awesome to crumbling at the touch -  I guess, block-walls are not strong enough here to carry even just the light-weight roofs single family homes usually have here.

So we had placed the rebar for these concrete columns and the cariola frames of the doors on top of the rebar mesh before poring the slab, so they are firmly planted inside of the concrete.

[slab with rebar and doors sticking out]

Now, the spaces between the columns and doors are filled with blocks. 

I have three window heights - 180, 120, and 100 m (6', 4', 3'4") - but in the end they all should reach the same height in the finished wall. Thus, below the large windows only two layers of blocks were needed, below the regular windows four layers, and below the kitchen-window 5 layers of blocks are placed. The rest of the walls need eleven layers. Oh, in the bathrooms I have some small narrow windows along much of the wall, to ensure adequate ventilation and avoid too much moisture to build up. Underneath these windows there are eight layers.

[wall with two, four layers of blocks]

These special bathroom windows will not have glass in it, but only mosquito-netting. For the other windows we prepared cariola frames, similar to what we had done for the doors. 

[ bathroom wall]

Once the wall-pieces below the windows were completed, we installed the frame by welding them to the rebar the are at the center of the columns.

That sounds very easy and simple. In theory it is. In practice, however, that is a very tricky task! The rebar is not very stable but, as long as there's no concrete around it, it flexes easily. The window frame has to be exactly placed - it has to be vertical not slanting, and horizontal, not inclining in any direction, and exactly 1.5 cm overreaching the the blocks. The stucco that is later put onto the block-wall, to make it nice and smooth, is about 1.5 cm thick. If the window is not placed correctly, it will be very hard to get a nicely looking stucco applied later!

[window frames installed]

Well, this is not something the folks here do often. Heck, it is the first time, since I came up with the idea. So it took quite some trial and error to get it right. Some windows had to be cut out and rewelded multiple times until they were correct.

[window 2 rewelding]

With windows in place now, one team started installing the plywood forms for the corners, and columns on each side of the door- and window-frames. Once a few of them were in place, we created the appropriate concrete mix and pored it inside. With a 2 1/2 m long rebar stick the concrete was pushed down all the way after each bucket full was pored, to ensure a full column, without holes.

When we removed the form the next day, it showed whether that compacting was done sufficiently or not. 

[holes in the columns]

The door and window-frames were built using 3" cariolas - the are 7.5 cm wide. The wall however is going to be 13 cm thick. So on one side of the frame I needed to place something to make up for the missing 6.5 cm.

I decided to cut standard 2-by-6 into 3 stripes, and install these flush with the cariola. The advantage of this is, that later I can attach the actual door-frame - the nicely looking one made of teak- or laurel-wood - to this wooden stripe - which is much easier than to concrete, or even worse to metal with concrete behind it! Also, since the window frames were very hard to install exact location, there are variations in how thick that strip had to be. Again, much easier to accomplish in wood, than anything else.

[door column with wood in place]

In order to keep that wood securely attached to the concrete column I thought I'll drill screws into it, letting them stick out in the back, so they will be embedded in the concrete. No need to drill holes for ankers!

Another interesting building code specialty here is this: the blocks are not laid all the way to the top of the wall, but 20 to 40 cm lower. On top of the blocks they cast another form for a "viga" (spanish for beam). Again, this is to strengthen the structure, tie all the block-wall pieces and columns together, and create a strong uniform base to put the ceiling or rest the roof trusses on.

It took almost three weeks to get the walls done. 

Lessons I learned:

First, since the rebars and door-frames were not placed exactly and firmly there was a lot of difficult finnagelling necessary to get the walls completed. Yes, when the foundation is not right, the longer you wait, the harder it gets to correct issues!

Secondly, It's difficult to install the window-frames exactly as they are needed. However, the more effort is made placing them, the easier it is later to create the casts for the columns and poor concrete. And, the easier it is later to apply the plaster.

Thirdly, when cutting pieces of rebar to measure it is not sufficient to place the in the general area where they will be needed. Because anybody may just decide to grab anything they see anywhere and cut a piece off of it! Then, when the original piece is needed it's nowhere to be found anymore, and has to be cut again! While the crew is waiting dwiggling their thumbs! Next time, I'll put some kind of marker on it. Maybe a piece of yellow "caution" tape, or such. And tell the folks, if they  touch one of these items with such a marker, they'll lose their job!!!

What went well, though, is: because everybody is so used to improvise all the time about anything, the workers were able to compensate for all the little difficulties and inaccuracies encountered! And, all in all, the walls went up relatively quickly, and appear to be sound and generally nice!