ToughButterCup Posted November 28, 2017 Share Posted November 28, 2017 Building on this thread, the question the fabricator has asked me whether we want the steels painted or galvanised? Well, I suspect that galvanising, while excellent, would be too expensive. The steels hold a structure (a curtain wall) that is external to the heated envelope, and they form one corner of the house. Has anyone got any experience of painting steels? What's the best paint to use? Is it the sort of job that a self-builder can do well enough? Got any trade names for an appropriate paint? We are about a mile or so inland (and more importantly down wind) from the sea. Blown salty wind is only a problem in winter. (I can taste it) Link to comment Share on other sites More sharing options...
Dudda Posted November 28, 2017 Share Posted November 28, 2017 If you can taste salt in the air any time of the year you need to galvanise it. We tried to save money on a university building for exposed steel columns and got the best paint available which was factory applied and its showing signs of rust now which is 5 years later. Project is 3km from the sheltered bay, about 4km from the sea. Last year on another building on the same university campus we galvanised everything, even some steel immediately inside the front door as the door might be open a lot with all the student traffic. 1 Link to comment Share on other sites More sharing options...
PeterW Posted November 28, 2017 Share Posted November 28, 2017 If it’s being painted then it needs to be blasted first and as soon as they do that it starts to corrode. I would get them to paint it as they do it day in and day out. It’s Red Oxide normally too. 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted November 28, 2017 Share Posted November 28, 2017 If the steels are semi exposed I would galvanise. Link to comment Share on other sites More sharing options...
Construction Channel Posted November 28, 2017 Share Posted November 28, 2017 (edited) I’m with Peter. Get the steel fabricators/merchants to give you a price for either. I suspect galvanising will add a LOT as I doubt they will do it in house so there will also be another set of transport costs. Getting them to blast and prime is surprisingly cheap. This should stop the corrosion while in transport then you can put a couple more coats when it gets to site. Red oxide and a roller takes no time at all. You may need to look into itumescent paints though especially if they are not being covered. Edited November 28, 2017 by PeterW Typo Link to comment Share on other sites More sharing options...
IanR Posted November 28, 2017 Share Posted November 28, 2017 (edited) Is it planned for the steels to remain visible, as in the image on you linked thread? If so, I wouldn't go with galvanised unless you are happy with a very industrial look. The finish is aesthetically inconsistent, especially around touch points when it's in the tank. Even if a fixture was made to support them in non prominent areas, which would push the cost up further, the patterning and thickness of galvanising still varies a great deal. If the steels are to be visible, with the likelihood of damage occurring during handling on site, I'd get a corrosion inhibitor put on at the fabricators, perhaps red oxide or similar, then prepared and painted once installed. Looks like you are using a hollow section so don't forget to get the internal coated with something... wax-oil perhaps. Also, if they are visible, assuming welded (hollow) section rather than seamless will be used, get them to tuck the weld seam on the least visible side. Edited November 28, 2017 by IanR Link to comment Share on other sites More sharing options...
Dee J Posted November 28, 2017 Share Posted November 28, 2017 Galvanized is great, love the industrial look. Painted will quickly look terrible unless you get some high spec marine coating professionally applied. How about stainless steel? Box, iIbeam and PFC available. Or even engineered timber? Link to comment Share on other sites More sharing options...
nod Posted November 28, 2017 Share Posted November 28, 2017 2 hours ago, recoveringacademic said: Building on this thread, the question the fabricator has asked me whether we want the steels painted or galvanised? Well, I suspect that galvanising, while excellent, would be too expensive. The steels hold a structure (a curtain wall) that is external to the heated envelope, and they form one corner of the house. Has anyone got any experience of painting steels? What's the best paint to use? Is it the sort of job that a self-builder can do well enough? Got any trade names for an appropriate paint? We are about a mile or so inland (and more importantly down wind) from the sea. Blown salty wind is only a problem in winter. (I can taste it) Yes and yes All the house steels were hot dipped But I had two steel beam that wanted to galvanise that were left over from demolition To be used a cross both d garages I bought some galvanising paint from a bought yard shop used for painting the underside of boats very cheap A year on still no different than the dipped steels The underside and one face is exposed to the elements Link to comment Share on other sites More sharing options...
Onoff Posted November 28, 2017 Share Posted November 28, 2017 I've been having stuff fab'd for 35 years now. My fabricator charges £700/tonne for hot dip galvanizing done at Medway galvanisers. So whatever your tonnage of steel goes in, multiply by 700. They (Medway) also offer a powder coating service. Next down the line is shot blast and zinc flame spray. Pretty good tba. Not as good as hdg above though. I use Beever Ltd in Tunbridge Wells. Last personal thing I had flame sprayed was my brothers astronomy pier. Got them to paint it too. You can also powder coat over it. Then it's stuff in a can. Red oxide is the old favourite. Micaceous iron oxide is pretty good. All the PSA stuff we used to do had to be done in it. Galvafroids a bit rough. Beware the conman who offers galvanizing when it is in fact zinc flame spraying. Similarly "cold" galvanizing - aka out of a can. I'd never btw powder coat bare steel even if it's been blasted. Once there's a crack in it, water gets in. Link to comment Share on other sites More sharing options...
PeterW Posted November 28, 2017 Share Posted November 28, 2017 The other - slightly random - option is to go for a Corten finish and let it rust ..? I think you would need your SE to sign off on it but I think it’s a really attractive finish and if it’s not a structural part of the main house then may be seen as “external” to the fire regs ..?? Link to comment Share on other sites More sharing options...
ToughButterCup Posted November 28, 2017 Author Share Posted November 28, 2017 3 hours ago, IanR said: Is it planned for the steels to remain visible, as in the image on you linked thread? [...] Looks like you are using a hollow section so don't forget to get the internal coated with something... wax-oil perhaps. [...] Also, if they are visible, assuming welded (hollow) section rather than seamless will be used, get them to tuck the weld seam on the least visible side. Yes, they will be visible, but not all of it (them) The points you make about the invisible parts are excellent. Thanks. As you will know, the budget has recently shrunk a good bit, so galvanising is out I am afraid. So it looks like the red leading (iron oxide) and internal wax oil is the most likely. Yes, I know it won't look the best, but...... Link to comment Share on other sites More sharing options...
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