Dumaguete Info Search


Steel bars for house construction

Discussion in 'Expat Section' started by Karl, Apr 9, 2013.

  1. Karl

    Karl DI New Member

    Messages:
    6
    Trophy Points:
    46
    Ratings:
    +0 / -0
    Hello everybody. We are new here in this forum.
    We are constructing a new house and we used to buy many of our construction materials in Dumaguete.

    Since we are located near the sea side we have planned to use galvanized steel bars for the roofing.
    construction of our roof.
    So we tried to find galvanized angle bars and flat bars.
    But wherever we asked in Dumaguete for galvanized steel, it was not available.

    We have heared, that some roofings in Dumaguete were constructed using galvanized steel.

    Does anybody know where to buy galvanized steel in Negros ?
    Or do we have to get it from Cebu somewhere ?
     
  2. john boy

    john boy DI Forum Patron

    Messages:
    1,971
    Trophy Points:
    226
    Occupation:
    Retired
    Location:
    Wirral near Liverpool UK
    Ratings:
    +291 / -0
    Can't help you there Karl, but welcome to the forum.
    Sure someone will be able to advise you as where you can find your requirements
    Good luck with your project...JB
     
  3. SteveB

    SteveB DI Forum Adept

    Messages:
    388
    Trophy Points:
    153
    Ratings:
    +17 / -0
    I have never seen galvanized bars in Dumaguete and I never considered using them. However, whether you use galvanized steel or the more common iron bars, it might be worth a trip to Cebu anyway. When I built my house in Valencia, I bought all my steel and iron (angle iron, flat bars, deformed bars, furrings, purlins) from World Wide Home Depot in Cebu and had it shipped here. I saved over P100,000 even after shipping costs. WWHD provided free shipping to the pier in Cebu and looked after the logistics of getting it to Dumaguete with Cokaliong Shipping.

    A cheaper alternative to steel might be to use rust inhibitor and red-oxide on the bars as soon as you receive them then touch up any welded areas after. Galvanizing only protects from surface corrosion anyway. If corrosion is a big concern for you and since you will surely be screwing into the metal, you might be more concerned with problems caused by galvanic corrosion (commonly called dissimilar metal corrosion). Since the screws, steel roofing and structural metal may not have the same electrical potential, you may be setting yourself up for bigger problems. A simple solution is dipping your screw threads in red-oxide and wet-installing them. I have attached a picture of galvanic corrosion (this type of corrosion has nothing to do with galvanized steel. It is simply the name given to the chemical reaction of dissimilar metals contacting each other in the presence of an electrolyte).
     

    Attached Files:

  4. firefly

    firefly DI Senior Member

    Messages:
    971
    Trophy Points:
    0
    Ratings:
    +17 / -0
    Roof construction made by purlins.
    There are 3" and 4" galvanised purlins, but no galvanised angle bar.
     
  5. OP
    OP
    Karl

    Karl DI New Member

    Messages:
    6
    Trophy Points:
    46
    Ratings:
    +0 / -0
    Thank you very much for that advice.
    I will take up the trace for ordering with home depot from Cebu. This might be a good option.

    We had bigger problems with the quality of the so called black angle bars.
    Often the delivered angle bars were so rusted, that even after cleaning the paint did not stick well. And we had lost a lot of time in removing the rust.
    the other time the drivers had distributed old oil from the truck on the steel bars, to keep the rust away.
    And again, we hardly could remove the oil from the steel and had serious difficulties in painting.
    One time the delivered angle bars were 3mm instead of the ordered 5 mm thick.

    So my last hope was now to get galvanized angle bars.

    The corrosion in the wholes of the screw of the steel construction is my biggest concern.
    I am thinking to protect the whole steel construction with a sacrificial anode, what is also used as standard in heating systems, were usually different materials are installed.
    Does anybody have some experience with such a kind of sacrificial anode protection ?

    My measures against corrosion were:
    - zinc painting of all steel bars (+ 2 additional coatings)
    - welding of additional angle bar as extension at the side of the beams.
    So if a screw is installed, it will be drilled in that extension, not in the beam.
    So in case of corrosion, the beam is not touched, only the extension might be rusting.
    - sacrificial anode

    Before I had organized some galvanized purlins from Cebu.

    A construction near the seaside is a big challenge.
    So any ideas are welcome.
     
  6. firefly

    firefly DI Senior Member

    Messages:
    971
    Trophy Points:
    0
    Ratings:
    +17 / -0
    Removing the rust is useless, just use rustconverter, it is a very thin liquid that will convert the rust in a black solid oxide layer.
    After that use red lead paint.
     
  7. jimeve

    jimeve DI Forum Luminary Highly Rated Poster Showcase Reviewer Veteran Army

    Messages:
    2,938
    Trophy Points:
    401
    Occupation:
    retired.
    Location:
    Philippines.
    Ratings:
    +1,259 / -0
    Blood Type:
    A+
    After using the rust converter, make sure you wash down the metal or the rust will come back
     
  8. OP
    OP
    Karl

    Karl DI New Member

    Messages:
    6
    Trophy Points:
    46
    Ratings:
    +0 / -0
    Thanks for that additional information.

    One question came up in my mind:
    After using rust converter, was the paint sticking well on the cleaned steel or was the rust returning after a short while on the painted steel ?
     
  9. jimeve

    jimeve DI Forum Luminary Highly Rated Poster Showcase Reviewer Veteran Army

    Messages:
    2,938
    Trophy Points:
    401
    Occupation:
    retired.
    Location:
    Philippines.
    Ratings:
    +1,259 / -0
    Blood Type:
    A+
    If you do it properly, read the instructions on the tin. Wash off with water, then use metal primer, wound not use red lead.
     
Loading...