chiangrai Posted November 17, 2016 Share Posted November 17, 2016 I want to put a loft in my living room.Just a small one not much bigger than a double bed. The room has concrete posts in the corners with horizontal lengths of metal going around the room on top of the concrete posts.I think the metal is called box metal or something.It's 3cms by 7cms and hollow in the middle. So what I'm wondering is what can I make my cross beams for the loft out of. The longest one is 4m 20cm.If I can find out what I can make that one out of I will make the rest out of the same stuff. A 4m20cm beam.Can I make it out of wood,if not what kind of metal. Would you attach it to the 4cm by 7cm metal on top of the concrete post or put in a new post. The concrete posts are not located where I will attach the beams. I hope you understand what I'm trying to explain.I've never done this sort of thing before. Would love some advice. Link to comment Share on other sites More sharing options...
melvinmelvin Posted November 17, 2016 Share Posted November 17, 2016 (edited) ---------------------------------------- ! ! ! ! ! B ! ! !------------------ ! ! ! ! ! ! X ! !--------------------------------------! you have a room like X? and want a loft like B in one corner? put in a steel post at the !- intersection in B and use overhead steel beams what kind of steel? ordinary carbon steel (Lek Dam) or slightly higher tensile strength (Lek Niao), inexpensive stuff could of course use strong hardwood, mai takiang, mai teng, mai daeng or mai sak, strong - long lasting - not inexpensive. if using steel, make sure to have it spray painted in a car paint shop, rusts very very quickly in LoS unless the surface is neutralized one way or the other. (could use stainless steel, but an unncessary cost in this case I think) aluminium would be a viable alternative Edited November 17, 2016 by melvinmelvin Link to comment Share on other sites More sharing options...
chiangrai Posted November 17, 2016 Author Share Posted November 17, 2016 Thanks mate, It's great to have some one who knows the terms in Thai. My wife says what we have is Lek Gong(box metal). So would you know if the Lek Gong 4 by 7cm is strong enough for a 4m20cm beam with no post to support it . It goes straight across the room and I don't want to put posts to support it. If not I will look for Lek Niao.or something better. I would love wood but I probably can't afford it. Link to comment Share on other sites More sharing options...
melvinmelvin Posted November 17, 2016 Share Posted November 17, 2016 I am on thin ice now. But a few thoughts which might be helpfull (or might not). Your wife says Lek Gong, my guess is that the Gong refers to the shape rather than the material itself. You say 4x7 cm Lek Gong, fair enough, but the important part here is the thickness (NA) of the steel, I assume that 4x7 is the outside measure of the metal. In order to have an idea re strength you would need to look at the thickness. 4 meters and a bit is quite a stretch. What weight is it supposed to carry? Whats the loft for? Storage? Sleeping? As far as I understand you talk about canal shaped steel (maybe your wife says Klong rather than Gong?) A 4x7 canal beam can take quite some weight. 8 or 10 mm thickness of the canal steel and I would sleep quite comfortably up there. Loose ends here man. You should specify a bit more re what you want to do and expected loads etc. Link to comment Share on other sites More sharing options...
eyecatcher Posted November 17, 2016 Share Posted November 17, 2016 Can i suggest the OP starts again with what he wants and what he has, as it will make answering easier. There are 20 questions I would want to ask before even taking a stab at suggesting 4cmx7cm steel!!! I can bend that over my knee. If you intend to carry both live and dead loads then 4m span requires steel of at least 10x5cm, where will it be carried...certainly not on tiny roof beams that are only designed to carry a light roof structure. Also remember a timber floor, 10x5cm floor joists can only span 1.5m before they need support so 4m requires 2 mid span beams....thus making your floor much thicker that you may want....(regardless of what species of timber it is) How will you access it? ladder,staircase; a loft access needs trimming out; often needing more steel/timber/design. There will be a solution but you need to be specific and if you really are as novice as you say (which you are not, having asked for directions on many many jobs here) then this little job is a diy job too far and you need to get some locals involved. So will you be putting a bed up there, your tools, another woman or building in an astronomical telescope. Link to comment Share on other sites More sharing options...
chiangrai Posted November 18, 2016 Author Share Posted November 18, 2016 O.k Guys, Thanks for your help and thanks for your patience, 14 hours ago, eyecatcher said: 4m span requires steel of at least 10x5cm, The loft is tiny,just big enough for a double bed.You crawl up there and sleep,there is no room to stand up,there is no room for storage. I had my Thai Guy in,the guy who built it,and he said he would just weld this 4 by 7cms box metal onto the same box metal that he used as beams. The ones which "eyecatcher"referred to as" tiny roof beams that are only designed to carry a light roof structure. " That was when I decided to open a post and get advice on whether I should maybe use some stronger metal. So what do you think..If I can't attach to the beams I may need to put a post attached to the wall on each side but I really don't want to put a post in the middle of the floor. 14 hours ago, eyecatcher said: 4m span requires steel of at least 10x5cm, What exactly do I go to the shop for............what's it called.....if I get these posts and one beam I will be well on the way. Is welding the best way to connect them or are there brackets you can buy. As well as The Thai builder there is a metal worker shop I know.May be he can get the stuff and cut it.He would even come and install it.He would even tell me what I need but I'm afraid he would choose stuff that is too light. A 4m+ beam with posts on each side...what do I make them out of. All help much appreciated. Link to comment Share on other sites More sharing options...
MikeyIdea Posted November 18, 2016 Share Posted November 18, 2016 (edited) I had a loft built in my daughters room. The room is 3.5 * 2.9 meters and I chose to make the loft 2.9 * 1.55 meters. Basically, it goes from one side to the other 155 cm out so that it fits a 5 foot bed. It wasn't worth it to make it shorter and have to think about how to clear the side "hanging in the air" Frame is 7 * 5? cm rectangular metal going into the wall a few cm with 1 inch * 3-4 mm bars welded across. I told cha^ng that we would be a couple of 100 kilo farangs up there and he welded a bit more, that's all... I wondered about no pillars but it's holding up just fine. Good to do when the room is small. I get in the wardrobe and the sofa under the bed Note the detail work on the wall I figured a soon teenager would fill the wall with posters so I happily didn't care at all Mikey Edited November 18, 2016 by MikeyIdea Link to comment Share on other sites More sharing options...
chiangrai Posted November 18, 2016 Author Share Posted November 18, 2016 That's very close to what I'm doing. Did you cover the metal with wood,I was thinking of doing that. I'm thinking now that if I go to the metal worker and ask him what metal do I need and then say that's not strong enough and ask him what's stronger and go through that process a few times he will come up with something that looks like it's strong enough.Then I would get him to cut it into the lengths I want. Unless some body comes up with Then should I just get it welded on site or are there nice brackets you can buy. Link to comment Share on other sites More sharing options...
melvinmelvin Posted November 18, 2016 Share Posted November 18, 2016 ordinary carbon steel will do (Lek Dam or Lek Niao (a wee bit higher tensile strength)) (I would bolt rather than weld) ordinary Lek Dam and Lek Niao is rusting faster than lightning, whenever I buy such steel I get it spraypainted in a car paintshop Link to comment Share on other sites More sharing options...
cornishcarlos Posted November 18, 2016 Share Posted November 18, 2016 If you do not want support posts, which is understandable, have you considered suspending the cross beams from the roof structure ? Stainless cable would work, looks good too :) Link to comment Share on other sites More sharing options...
eyecatcher Posted November 18, 2016 Share Posted November 18, 2016 OK, What MickeyIdea has created is a mezzanine floor; basically just a bed deck within a room....so they both share the same ceiling. if thats what the OP wants then yes, providing you have two supporting walls at each side then you can get away with smaller section steel. So there are a few ways to achieve this. one way is to run two deeper section steels, onea t the front, one at the back and face fix them to a steel plate which int urn has been rawl bolted/anchored to the wall. weld the two steels in between. then run smaller section steels, (and the depth matters here so check the spans.) at 400mm c/c and burn them to the first two steels, so you have a set of floor joists. setting them at 400c/c means when you fit a ply/osb floor it should mean no ply cutting, a perfect fit. if your joist spans are over 2.7m then you should be fitting 2 steel spacers at 1/3 centres., otherwise just one in the middle is sufficient. Another method, just like fitting a ceiling. you can bolt say some 50x75 steel around the perimeter walls (if you have 3 walls) and then as above just set out all the floor joists using the same section steel and again cover it with plywood. a third method which I would only ever do if building the walls from scratch would be to build the steel into the walls. the blocks here are too thin, and the bricks don't really lend themselves to being kangoed out to make a pocket to carry steel ends. if its heavy steel ok, but then your hole would need to be big enough to incorporate a concrete padstone. its an option but prepare for a big mess/demlition job. So if you want this private area between walls then no need to use the columns, or the roof steel or add an extra post; an its quite straightforward. Link to comment Share on other sites More sharing options...
MikeyIdea Posted November 18, 2016 Share Posted November 18, 2016 (edited) 3 hours ago, chiangrai said: That's very close to what I'm doing. Did you cover the metal with wood,I was thinking of doing that. I'm thinking now that if I go to the metal worker and ask him what metal do I need and then say that's not strong enough and ask him what's stronger and go through that process a few times he will come up with something that looks like it's strong enough.Then I would get him to cut it into the lengths I want. Unless some body comes up with Then should I just get it welded on site or are there nice brackets you can buy. chiangrai, I have been here over 25 years, I have stopped trying to improve things to get "my" acceptable standard a long time ago and I think differently nowadays. I start by thinking - Do I think that the Thai metal worker who will do the job knows what he is doing well enough? If yes, then I just keep my sanity and go with it. That's why I am so trouble free in Thailand All the metal I got came with a dull reddish/colour so they had rust protection, that is a must. He will weld and that will be good enough. I have not covered the metal with wood, just painted it black. Just say 300 - 400 kilo 3-4 farang and point up where the bed will be and don't worry after that, he will do a good enough job Trust him Edited November 18, 2016 by MikeyIdea Link to comment Share on other sites More sharing options...
MikeyIdea Posted November 19, 2016 Share Posted November 19, 2016 (edited) Additional information My house is a 40 year old 1 storey twin house in Bangkok and walls are the 10 cm blocks. The walls are certainly not made to take any weight. 2.5 cm diff in 2 metres. If the back of the Ikea PAX wardrobe doesn't bend , then it must be the walls :) They/he will do all the welding on side for sure. I saw no brackets or pre made stuff. The beam ends going into the walls are literally just that, they go in a bit on one side and they never touched the wall surface on the other side. They never touched the beams. In my case I used the same guys who renovated parts of the house, I really don't know the price but it was cheap. The stairs and guard rail in teak were expensive, cost 20,000 I have had the whole family up there (200 + kilos) and I felt absolutely nothing. It'll' will easily take another 100 kilos. That's for 2.9 metres with 7 by 4-5 cm It could be a good idea to "fit the hanging side" from the ceiling. The guys did that with "the middle" when they built the attic floor I really do think that you can just trust your Thai experts. Just carefully tell them 4 farang 400 kilos or whatever you want with some margin and sit down and relax and close your eyes Mikey Me and Idea playing in Sweet Home 3D (free) Edited November 19, 2016 by MikeyIdea Link to comment Share on other sites More sharing options...
Don Mega Posted November 19, 2016 Share Posted November 19, 2016 Dunno bout you guys but Ive purchased a lot of RHS and SHS here in Thailand and it seems anything sized in metric is extremely hard to come by, Everything seems to be in imperial (4cm x 7cm wold be 1.5inch x 2.75 inch) dimension but thickness is metric . If it were me building this that 4m free span I would be looking to use a 175mm x 175mm H Beam at minimum. Link to comment Share on other sites More sharing options...
chiangrai Posted November 19, 2016 Author Share Posted November 19, 2016 I'm thinking now that if I go to the metal worker and ask him what metal do I need and then say that's not strong enough and ask him what's stronger and go through that process a few times he will come up with something that looks like it's strong enough.Then I would get him to cut it all up and get the Thai builder to install it. He can weld but i would prefer if I could use nuts and bolts and bolts "If it were me building this that 4m free span I would be looking to use a 175mm x 175mm H Beam at minimum. If it were me building this that 4m free span I would be looking to use abutt\]' If it were me building this that 4m free span I would be looking to use a 175mm x 175mm H Beam at minimum" 2 great quotes guys. I do not trust my Thai Guy or the Thai metal worker.They chose stuff that always too light . . Link to comment Share on other sites More sharing options...
eyecatcher Posted November 19, 2016 Share Posted November 19, 2016 8 hours ago, Don Mega said: Dunno bout you guys but Ive purchased a lot of RHS and SHS here in Thailand and it seems anything sized in metric is extremely hard to come by, Everything seems to be in imperial (4cm x 7cm wold be 1.5inch x 2.75 inch) dimension but thickness is metric . If it were me building this that 4m free span I would be looking to use a 175mm x 175mm H Beam at minimum. Not sure where you have plucked out those British steel tables from but you clearly do not understand any of the column headings. a H section is different to an I section. H is a universal beam and used for major heavy loadings. I used to use these tables on every job I designed, they do not give spans...why? because the tables dont know how much you are going to load the steel and where you are going to restrain the steel to stop it deflecting or bending or shearing. As an example, two simple 175mm x100 I sections, 4m long one for each wall skin can carry the weight of all the upper floor of a two storey house. tons and tons....but if the flange and web thickness are 1mm less then just tons! A more critical thing to worry about here is the standard of the welding. if they are not being supported on a wall or shelf angle then the onus is on the weld and rarely the failure of the steel Link to comment Share on other sites More sharing options...
Don Mega Posted November 20, 2016 Share Posted November 20, 2016 13 hours ago, eyecatcher said: Not sure where you have plucked out those British steel tables from but you clearly do not understand any of the column headings. a H section is different to an I section. H is a universal beam and used for major heavy loadings. I used to use these tables on every job I designed, they do not give spans...why? because the tables dont know how much you are going to load the steel and where you are going to restrain the steel to stop it deflecting or bending or shearing. As an example, two simple 175mm x100 I sections, 4m long one for each wall skin can carry the weight of all the upper floor of a two storey house. tons and tons....but if the flange and web thickness are 1mm less then just tons! A more critical thing to worry about here is the standard of the welding. if they are not being supported on a wall or shelf angle then the onus is on the weld and rarely the failure of the steel I plucked them from here, http://www.thesteel.co.th/. Not sure why you are dribbling on about an I Beam when I said H Beam but good to hear it would be overkill for the application, that should ensure the loft does not collapse !! Link to comment Share on other sites More sharing options...
chiangrai Posted November 20, 2016 Author Share Posted November 20, 2016 H ow expensive is this H bar.How do I join it together. I would prefer brackets. Link to comment Share on other sites More sharing options...
eyecatcher Posted November 20, 2016 Share Posted November 20, 2016 Please let me just clarify. Steel comes in many sections H I C U T L but you do not want be using H which is a universal beam. Its too heavy, the weight per metre for example of that 175mm beam is 40kg/m, and that means it needs a serious padstone each end or else bearing plates that are likely to to just dissolve the crappy blcok walls here. An I section at around 16kg per metre over a 4m span such as a 150x100 will be more manageable. But, as the discussions have been leading towards the use of smaller box sections such as 70x45 or 100x50 then use those; they are cheap enough. Just for comparison, the 100x50 box section say 2m thick will cost you around 600/700 bt for a 6m length. Someones less than cost effective solutions at 40kg/m for a 4m length would cost you about 9500bt Link to comment Share on other sites More sharing options...
MikeyIdea Posted November 20, 2016 Share Posted November 20, 2016 (edited) A couple of comments here 1) If you push on things that Thai workers have never used before, then don't think that you will get a stronger end result 2) If you push on things that Thai workers have never used before, then don't blame them if they don't put it together well 3) Don't think that you will get a stronger total solution by increasing beams to ridiculously heavy 175*175. That choice would make more than the loft collapse. Definitely a weaker total solution than the Thai expert recommended 4) Your Thai expert probably knows that bearing plates are likely to to just dissolve the crappy block walls here. Thank you eyecatcher, excellently worded If you want strong, then go down to the local metal shop and check what they have. They have 7*4 but you want bigger so let the owner point out next size and the next size. Measure them and go and talk to your Thai expert. Ask him and look at his face at the same time. If it looks like "waste of money" then it is still OK If he starts to look worried, then he has a valid reason that you don't know of I can't help it, I actually trust the guys who did the work for me. They're chronically blind when it comes to nice finish but they clearly know how to build strong enough well Mikey PS Approx. 100 by 50 sounds great to me. DS Edited November 20, 2016 by MikeyIdea Link to comment Share on other sites More sharing options...
chiangrai Posted November 21, 2016 Author Share Posted November 21, 2016 Thanks for the help guys, I was thinking to use a length of the same stuff I'm using as the beam as posts instead of using the existing beams for load bearing Is that necessary. I have two people now saying 100 x50 by 2mm thick box metal is best. Link to comment Share on other sites More sharing options...
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