Prime Welds Before Laying Roof

[Greenside]

We're getting towards the end of the steelwork on our house in CM. I assume the welds should be primed before the insulation and tiling commences - is that standard practise and who normally undertakes it: the welding guys or the tiling folk?

[onionluke]

Hello ,

Do have one contractor or are you paying tradesmen for the diffrent works. It makes sense to finish the job while the men are up there. Start by pointing out the welds out to the fella in charge .

You should clean the slag off the welds , clean up with a wire brush and coat the area in primer . While you have men up there you should also clean up any obvious rust and then primer . This will protect the welds from future corrosion and hopefully prevent unsightly rusty water runs appearing at a later date . What kind of tiles are you installing ? I am only asking because the roof I had built 3 years ago has become a roost for lots of little birds due to the space left by the contour .

[Artisi]

Ideally all weld areas should be vigorously and carefully wire-brushed to remove all slag and weld splatter together with any burnt and damaged paint. It should then be primed with a quality red-oxide primer and preferably painted with a good coating of rust inhibiting paint. As to who does it, depends on who allowed for it in their quote - usually the building contractor would allocate the work - unless of course YOU are the contractor - so you decide.

[Greenside]

Thank you both. We have a contractor but the quote didn't go down to that detail level and I just want to ensure they don't cut any corners before the roof crew leaves and we have to waste time getting them back on site. Your point about rust and leaks is particularly helpful - I've been the victim of this before in an old house and the rust stains never really go away.

We're using Elabana Tiles and I hope they will be OK!

[powderpuff]

Onionluke is absolutely correct. Agree with wirebrush but you need this first

.

[tango]

The accepted procedure is to rustproof the steel beams on the ground before raising them to frame the roof. It is best to do this at least twice, with particular attention to the inside where water condenses and accumulates. The painting can easily be done by a few ladies from the moobaan: these female laborers are usual competent and inexpensive, just keep an eye on them and provide lunch and munchies( same goes for all your laborers), with a weekly TGIF. The roof welding team are in demand, and consider themselves above this; besides, they usually have a waiting list of construction sites to go to. The roof-welding expert earlier will have advised you, having looked at the plans, what size and quantity to buy and rustproof before he arrives with his team. Preferred are 'C'-shaped lengths as opposed to totally enclosed beams to more easily gain painting access to the interior. Nonetheless, enclosed piping/beams can be rustproofed on the inside by placing on end in a bucket and then filled(these however retain condensation). Once erected, follow the advice given above and then repaint the welds, at least twice. I use grey-colored rustproofing to see where the rust forms; I suspect that the rust-colored paint one sees in frequent use is to do just the opposite. Ensure you buy and place radiant-reflective foil along each run from top to bottom leaving at least 2-inches of space from the roof tile. These foil rolls are 2000-3500B each, which is why many folks do not install, much to their chagrin later as they roast: stay beneath a roof with and one without; you will readily understand the advantage. That seems to be it on priming. Oh, and at least two coats of primer for walls, both new and old, before painting. Anything less will be obvious within a year. Have fun....

[Greenside]

I'm assuming from the advice above, that I should be getting the welders back in to clean and repaint these two sections as they don't seem to have chipped off the slag.

[doglover]

^^^^

I suppose you could bring back the welders but they won't be happy. In my opinion, all advice given thus far is spot on. Of course implementing the advice is the tricky part. And no doubt there are more welds than just those in your picture needing attention. I have never seen a Thai welder use a chipping hammer or a wire brush. Standard practice would be to not chip or wire brush and just slap one coat of dripping paint in half assed way as has already been done in your picture. So rather than disgruntle any of the workers you will keep throughout your build (or the welders if they are friends/relatives of the preceding) I would bring in labourers and pay them out of my own pocket to have it done the way it should be done. Proper chipping, brushing, painting will extend the life of your roof structure considerably but the Thais won't get it. Or if they do, they won't care. It is best to refrain from trying to have them "get it" and just move on. The cost of a couple workers for a couple days is peanuts compared to upsetting anyone. If you want to use the workers you have already, and they are willing, make sure you pay them as if it is extra work (in their minds it will be).

Explain to the temporary workers what you want done and pay by the day. Tell them there is no rush, they are being paid by the day, take the time to do the job right and they will make more money if they do. Make sure you are on site and point out every weld that needs attention and check that it is being done right. No doubt your permanent crew will be wanting to jump at getting those roof tiles on. Make them wait till the painting has been properly completed. There must be something else they can work on while waiting for the chipping/painting.

*I would also pick up some ear plugs for the workers as chipping welds can be hard on the ears which will equal less chipping. If they actually show any interest in wearing the ear plugs make sure to show them how they are properly fitted. Of course, safety glasses are really a must for the chipping but I'd be shocked if they actually would wear them*

[bankruatsteve]

From your photo... I've seen worse. But, it doesn't look that bad. What's the (perceived) problem? The steel appears to be primed and the welds are probably OK and as good as you will get with locall labor. ie: should be strucurally OK so what's this with the chipping? Good luck if you think you can hire somebody to do that. You might better be turning the attention to how the baths and kitchen area are being roughed in b/c local builders just don't know the western standards for that.

[katabeachbum]

When welding a roof, I demand all weldings brushed and primed same day as welded. Then they can go home

[wpcoe]

Is it standard/normal to use a rust-colored primer? I would think another color would be better, as if/when rust appears, it would be easy to spot.

[Greenside]

Is it standard/normal to use a rust-colored primer? I would think another color would be better, as if/when rust appears, it would be easy to spot.

Red Oxide Primer is pretty standard. I don't know if there is a different coloured alternative.

The end (hopefully) of this saga is, that having sent the architect who works for the contractor pictures of a dozen or so welds we felt were at least badly finished, the foreman got the welders back on site for a couple more days and then an engineer came out on the third day and checked the structure. He tells me it won't fall down in a hurry (or even slowly).

I hope to see the foil insulation starting to go up tomorrow or Saturday.

[bankruatsteve]

There is a primer alternative that is grey - or along that line - at least one brand is "Jotun". I like that b/c it doesn't look like rust to start with and makes a nice one coat if you're not fussy.

[wpcoe]

I think I would prefer gray, for the same reason: it doesn't look like rust. And, if/when rust could start, you could see it better.

[Soutpeel]

I'm assuming from the advice above, that I should be getting the welders back in to clean and repaint these two sections as they don't seem to have chipped off the slag.

Based on that photo..I would be getting the welders back to re-weld those joints ....although the photo is not completely clear....those welds are cr*p and have been "birdshitted" in....a real welder would be ashamed.....Very apprant that these guys are not welders but mearly "rod burners"...

Also on the subject of priming.....red oxide/grey oxide is not corrosion protection per se...the products name is the give away...its a "primer"....it's a product which prepares the surface for subsequent coating with "proper" corrosion protection.

In a corrosive enviroment....rust will "bleed through" a red oxide/grey oxide prime in about 2-3 months unless other layers of corrosion protection are applied.

With being said, Thailand per se is not a overly corrosive enviroment and the further you get away from the sea the better it gets...so if you are in Issan or somewhere similar, I wouldnt be too bothered about the corrosion resistance properties of red oxide prime....and would suggest its put on as a purely cosmetic measure...ie covering up sh*t welding...

[tassini]

I'm assuming from the advice above, that I should be getting the welders back in to clean and repaint these two sections as they don't seem to have chipped off the slag.

Based on that photo..I would be getting the welders back to re-weld those joints ....although the photo is not completely clear....those welds are cr*p and have been "birdshitted" in....a real welder would be ashamed.....Very apprant that these guys are not welders but mearly "rod burners"...

Also on the subject of priming.....red oxide/grey oxide is not corrosion protection per se...the products name is the give away...its a "primer"....it's a product which prepares the surface for subsequent coating with "proper" corrosion protection.

In a corrosive enviroment....rust will "bleed through" a red oxide/grey oxide prime in about 2-3 months unless other layers of corrosion protection are applied.

With being said, Thailand per se is not a overly corrosive enviroment and the further you get away from the sea the better it gets...so if you are in Issan or somewhere similar, I wouldnt be too bothered about the corrosion resistance properties of red oxide prime....and would suggest its put on as a purely cosmetic measure...ie covering up sh*t welding...

Got to agree with this post, those welds in the picture are crap. Having said that it is very hard to find decent welders here in Thailand especially if you are out in the sticks. Most of the builders here do everything from groundworks to finishing works and everything else in between. They have never been taught to do anything correctly just learnt from someone else who doesn't know what he is doing! that's why most houses here are so poorly built and finished. In most cases they burn through the steel sections and have to refill with weld. if you are able to supervise the construction yourself ask the welders to prepare a couple of samples for you. If they are like the ones shown in the picture ditch them and find someone else to do the work.

Tas

Tas

[Greenside]

Too late for further action now, I'm afraid. Many were redone and we're now assured that they are OK. The ones we can see certainly look better and we are using a contractor with a reputation to maintain so that's about the best we can do I think. Many thanks for the input.

Now if anyone knows about air conditioners, my thread of yesterday remains lonely and unanswered

[Soutpeel]

Got to agree with this post, those welds in the picture are crap. Having said that it is very hard to find decent welders here in Thailand especially if you are out in the sticks. Most of the builders here do everything from groundworks to finishing works and everything else in between. They have never been taught to do anything correctly just learnt from someone else who doesn't know what he is doing! that's why most houses here are so poorly built and finished. In most cases they burn through the steel sections and have to refill with weld. if you are able to supervise the construction yourself ask the welders to prepare a couple of samples for you. If they are like the ones shown in the picture ditch them and find someone else to do the work.

Tas

Plenty of good welders in Thailand, in fact Thai welders are sought after worldwide on construction/engineering projects and are some of the most skilled in the world.

As stated before, the guys who put in those welds are not welders, they are rod burners...

If you want good Thai welders you have to pay for them.....as the old saying goes...pay the peanuts get the monkeys...

[Soutpeel]

Too late for further action now, I'm afraid. Many were redone and we're now assured that they are OK.

Who assured you that they are ok....the Architect or builder..? ......sorry to say they wouldnt know a decent weld if they fell over it....not just in Thailand I might add...

[Greenside]

Too late for further action now, I'm afraid. Many were redone and we're now assured that they are OK.

Who assured you that they are ok....the Architect or builder..? ......sorry to say they wouldnt know a decent weld if they fell over it....not just in Thailand I might add...

An engineer sent by the contractor. I have to confess that I didn't ask him to produce a copy of his degree and certification but then, this being Thailand, I probably wouldn't have been able to understand them. I'm assuming he was more of the structural variety rather than say, a sanitary type since he and an assistant spent several hours clambering around the building looking at the welds.

[Soutpeel]

Too late for further action now, I'm afraid. Many were redone and we're now assured that they are OK.

Who assured you that they are ok....the Architect or builder..? ......sorry to say they wouldnt know a decent weld if they fell over it....not just in Thailand I might add...

An engineer sent by the contractor. I have to confess that I didn't ask him to produce a copy of his degree and certification but then, this being Thailand, I probably wouldn't have been able to understand them. I'm assuming he was more of the structural variety rather than say, a sanitary type since he and an assistant spent several hours clambering around the building looking at the welds.

I should have added to my list...the average structual engineer wouldnt know a decent weld either if it fell on him, again not just in Thailand....A structual engineer can specify the size and type of weld required, but as to quality of weld...naah....

[Greenside]

Too late for further action now, I'm afraid. Many were redone and we're now assured that they are OK.

Who assured you that they are ok....the Architect or builder..? ......sorry to say they wouldnt know a decent weld if they fell over it....not just in Thailand I might add...

An engineer sent by the contractor. I have to confess that I didn't ask him to produce a copy of his degree and certification but then, this being Thailand, I probably wouldn't have been able to understand them. I'm assuming he was more of the structural variety rather than say, a sanitary type since he and an assistant spent several hours clambering around the building looking at the welds.

I should have added to my list...the average structual engineer wouldnt know a decent weld either if it fell on him, again not just in Thailand....A structual engineer can specify the size and type of weld required, but as to quality of weld...naah....

And so the solution is.........

[Soutpeel]

And so the solution is.........

1. Get decent welders...suppose this is not an option now

2. hire a certifed welding inspector for a few hours (yes there are certifed welding inspectors in Thailand)

3. Go on the internet for a few hours and look up good weld quality versus bad (plenty of basic info about) and do it yourself, even with basic info you will see very quickly what consitiutes a good weld.

[Greenside]

Waay too late

[Beardog]

Waay too late

Looks like they are doing a decent job. The priming from what I can tell looks good.

[klikster]

And so the solution is.........

1. Get decent welders...suppose this is not an option now

2. hire a certifed welding inspector for a few hours (yes there are certifed welding inspectors in Thailand)

3. Go on the internet for a few hours and look up good weld quality versus bad (plenty of basic info about) and do it yourself, even with basic info you will see very quickly what consitiutes a good weld.

Looks like cold welds.

Never too late to get a good welder .. and someone who knows how to use an angle grinder. Leave portions of the weld to hold the structure together. Carefully grind out the rest of the welds .. not the tubing wall. Re-weld with good penetration.

Chip and wire-brush the welds .. try to find a good zinc-rich coating like CRC .. spray with the zinc coating then paint.

More important for the welder to know what good welds look like than for you to know.

[Soutpeel]

More important for the welder to know what good welds look like than for you to know.

Same as the fox looking after a chicken coop....

Of course you are correct in some respects, a real welder would know what a good weld looks like...but the rod burners you see "welding" structual framing are not welders....

[klikster]

Of course you are correct in some respects, a real welder would know what a good weld looks like...but the rod burners you see "welding" structual framing are not welders....

Um .. in what respects am I not correct?

Where did I say, "Find a 'rod burner'?"

Why the attitude? (obnoxious emoticon)

[David006]

Hello ,

Do have one contractor or are you paying tradesmen for the diffrent works. It makes sense to finish the job while the men are up there. Start by pointing out the welds out to the fella in charge .

You should clean the slag off the welds , clean up with a wire brush and coat the area in primer . While you have men up there you should also clean up any obvious rust and then primer . This will protect the welds from future corrosion and hopefully prevent unsightly rusty water runs appearing at a later date . What kind of tiles are you installing ? I am only asking because the roof I had built 3 years ago has become a roost for lots of little birds due to the space left by the contour .

...we had a painting team repaint the whole steel roof with rustproofing primer before the tiles went on they did it a second time after I pointed out that they had just done the easy bits!!....wondered about our feathered friends too...asked 'em to put wire mesh up there under tile (concrete) contour..builder said there were special plastic strip contoured things nailed under soffit...anyways bought a few hundred of 'em and they installed 'em...no birds but lots of geckos which get in from the inside through the down lights...

[happyjune]

Bankrutsteve post #9 :

You might better be turning the attention to how the baths and kitchen area are being roughed in b/c local builders just don't know the western standards for that.

Can you explain more please?