Footings, Columns,Beams, and Floor slabs

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Re: Footings, Columns,Beams, and Floor slabs

Postby sirineou » Sun Aug 19, 2012 1:38 am

Roger Ramjet wrote:sirineou,
What are the stairs made of? If it's a normal Thai house they'll be concrete. Other columns carry burden from the roof structure, the slab floors and the beams and don't forget the bathrooms, walls and with open areas such as verandas you're looking at opposing forces, both lift and carry weight. I used to have Mini Cad + 4, which to be honest was a pain. Nowadays the CAD programs they use work quietly work in the background and instantly give a solution.
As I said before, don't forget to cover the outside stairs as well or they'll break away from the house structure. They need to be part of the beams and also have either piles and footings, or both. Personally I would eliminate those two columns interfering in the space downstairs (it's only 4 metres wide) and I'd increase the load carrying capacity of the columns and beams.


I don't have outside stairs,
The stairs are concrete and are designed to fit between the columns providing room under them for a bathroom.
The first course of stairs has 13 steps each step having a rise of 17.92 cm and a thread of 21.23 cm the second course of stairs is 6 steps ,I had to change the riser and the thread slightly to fit the 6 steps with in the allowed space, so for these 6 steps the riser is .18cm and the thread is 20 cm
I had to do that, to keep all the steps the same size,and keep them with in d code, I am allowing for a 4 inch soffit.
I have given them instructions to , if the make any changes in the height of the structure, to devide the discrepancy among all the steps so that they keep them equal size.
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Re: Footings, Columns,Beams, and Floor slabs

Postby Roger Ramjet » Sun Aug 19, 2012 6:50 am

sirineou,
Okay, I couldn't see any of that in the other sketch-ups you posted, it appeared to be just one long staircase. I also surmised that the house would be built off the ground to stop flooding during the wet season. Don't forget to tell them to place rebar in the slab before the slab is poured to help support the staircase's diametrically opposed force. We had a beam under the staircase that we tied into with rebar before it was poured, but it appears you won't have that.
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Re: Footings, Columns,Beams, and Floor slabs

Postby splitlid » Sun Aug 19, 2012 7:11 am

sirineou wrote:I don't have outside stairs,
The stairs are concrete and are designed to fit between the columns providing room under them for a bathroom.
The first course of stairs has 13 steps each step having a rise of 17.92 cm and a thread of 21.23 cm the second course of stairs is 6 steps ,I had to change the riser and the thread slightly to fit the 6 steps with in the allowed space, so for these 6 steps the riser is .18cm and the thread is 20 cm
I had to do that, to keep all the steps the same size,and keep them with in d code, I am allowing for a 4 inch soffit.
I have given them instructions to , if the make any changes in the height of the structure, to devide the discrepancy among all the steps so that they keep them equal size.


seriously, all stair risers and treads should all be the same. 200mm for a tread is toooooo small.and what do soffits have to do with stairs??? 8)

oh, and you need a minimum of 2000mm head height as you walk up them there stairs.
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Re: Footings, Columns,Beams, and Floor slabs

Postby BKKBILL » Sun Aug 19, 2012 8:49 am

Here is a calculator. I’m sure you have already used one but for those in the planning stage. This one is for wood but it is the measurement that count.

http://www.blocklayer.com/stairs/default.aspx
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Re: Footings, Columns,Beams, and Floor slabs

Postby geordie » Sun Aug 19, 2012 9:03 am

the ceiling in the downstairs bathroom will be tight ?
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Re: Footings, Columns,Beams, and Floor slabs

Postby sirineou » Sun Aug 19, 2012 9:30 am

splitlid wrote:
sirineou wrote:I don't have outside stairs,
The stairs are concrete and are designed to fit between the columns providing room under them for a bathroom.
The first course of stairs has 13 steps each step having a rise of 17.92 cm and a thread of 21.23 cm the second course of stairs is 6 steps ,I had to change the riser and the thread slightly to fit the 6 steps with in the allowed space, so for these 6 steps the riser is .18cm and the thread is 20 cm
I had to do that, to keep all the steps the same size,and keep them with in d code, I am allowing for a 4 inch soffit.
I have given them instructions to , if the make any changes in the height of the structure, to devide the discrepancy among all the steps so that they keep them equal size.


seriously, all stair risers and treads should all be the same. 200mm for a tread is toooooo small.and what do soffits have to do with stairs??? 8)

oh, and you need a minimum of 2000mm head height as you walk up them there stairs.

the code is, no more than 8" rise, no less than 9 inch thread (ideally 10" thread) so the riser and thread can not possible be the same.
I have 7.08" rise well with in code and 9" which is also well with in code.( you were right about the thread on the 6 steps being to small so I increased it to 9")
I have 2.22 m headroom clearance under the stairs. I would have liked to have had more but that would had made my upstairs hallway too narrow. now it is 3.8 ft wide.I think 2.2 m headroom is more then adequate.
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Re: Footings, Columns,Beams, and Floor slabs

Postby MGV12 » Sun Aug 19, 2012 9:35 am

splitlid wrote:
seriously, all stair risers and treads should all be the same. 200mm for a tread is toooooo small.and what do soffits have to do with stairs??? 8)

oh, and you need a minimum of 2000mm head height as you walk up them there stairs.


Agree ... for comfort and safety you should be able to place your foot flat on each stair without overhanging. Measure your foot and [unless you are a ballet dancer :P ] you will see that 250mm [up to 300mm] really should be aimed for. Thai build stairs do tend to be 180mm rising and 200mm going but they have smaller feet :roll: You appear to have the space by making the half-landing smaller.

Building regs in the UK call for 2000mm head clearance but again that's something they ignore/overlook here ... in mitigation Thais are on average shorter but in some places even they have to duck.

Edit note: Written while you were posting the above sirineou

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Re: Footings, Columns,Beams, and Floor slabs

Postby splitlid » Sun Aug 19, 2012 10:20 am

sirineou wrote:the code is, no more than 8" rise, no less than 9 inch thread (ideally 10" thread) so the riser and thread can not possible be the same.
I have 7.08" rise well with in code and 9" which is also well with in code.( you were right about the thread on the 6 steps being to small so I increased it to 9")
I have 2.22 m headroom clearance under the stairs. I would have liked to have had more but that would had made my upstairs hallway too narrow. now it is 3.8 ft wide.I think 2.2 m headroom is more then adequate.



sorry, for the misunderstanding, i meant, all risers should be the same and all treads the same. not both the same.
and headheight i was talking about headheight clearance as you walk up the stairs. your upstairs landing needs to be cut back.
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Re: Footings, Columns,Beams, and Floor slabs

Postby Roger Ramjet » Sun Aug 19, 2012 10:31 am

splitlid,
splitlid wrote:sorry, for the misunderstanding, i meant, all risers should be the same and all treads the same. not both the same.
and headheight i was talking about headheight clearance as you walk up the stairs. your upstairs landing needs to be cut back.

I understood what you meant and I agree. Even with the architectural plans, I had to rework the whole of the stairs as the architect had made them for just Thais or people with very small feet. I might add it took me a long time with a lot of measurements on site to get it right. And my big "bay" window made it all the more complicated.
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Re: Footings, Columns,Beams, and Floor slabs

Postby BKKBILL » Sun Aug 19, 2012 11:11 am

Thinking a little more about your stairs. Any change in the rise or run for that matter on the same set of stairs would not pass code and be dangerous, fortunately using SketchUp making them all the same is quite easy if you make one then make that one a component.

http://www.youtube.com/watch?v=riNTxc-86pw

or

http://www.youtube.com/watch?v=DsplRdHEOCs

You will also need a support beam under your slab across the top of the stairs.
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Re: Footings, Columns,Beams, and Floor slabs

Postby sirineou » Sun Aug 19, 2012 7:35 pm

BKKBILL wrote:Thinking a little more about your stairs. Any change in the rise or run for that matter on the same set of stairs would not pass code and be dangerous, fortunately using SketchUp making them all the same is quite easy if you make one then make that one a component.

http://www.youtube.com/watch?v=riNTxc-86pw

or

http://www.youtube.com/watch?v=DsplRdHEOCs

You will also need a support beam under your slab across the top of the stairs.

They are all the same , the initial change was on a the second set of stairs
I was able to move the whole staircase back a litle, with out loosing much space in the bathroom, put that beam under the front of the hallway slab and maintain the 2 meter headroom
this is a close up of the main set of stairs ,
Image
the stair soffit I mentioned earlier is the flat part at the underside of the stairecase, when we construct staircases we construct that part first, , then the sides, then we place the steel in the "soffit" and then we place the front of the stair form (the riser). for commercial we want a 6" sofit, but for residential a 4" soffit will do.
as you can see my rise is well with in code at a litle more than 7 inch, and the Thread is 9.2 inch I could get a 10" thread if I wanted by changing the angle if the riser a little bit ( see the 10" (25cm) thread that I put there as an example) but I am not sure if I can explain that to the people doing the building with out me being there. What you think, should I try to get them to do it, or do you think I will confuse the heck out of them?
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Re: Footings, Columns,Beams, and Floor slabs

Postby Roger Ramjet » Sun Aug 19, 2012 7:45 pm

sirineou,
You have two sizes marked for the horizontal treads. One says 0.2339 the other 0.2500. Move the staircase back and get all of them even.
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Re: Footings, Columns,Beams, and Floor slabs

Postby sirineou » Sun Aug 19, 2012 8:38 pm

Roger Ramjet wrote:sirineou,
You have two sizes marked for the horizontal treads. One says 0.2339 the other 0.2500. Move the staircase back and get all of them even.

You did not read my post carefully, or I did not explain properly.
The horizontal threads are .2339 , which is 9.2 inches, The ideal would be 10 inch, and I can achieve that by changing the angle of the riser from 90 degrees to an angle greater than 90 degrees. the second measurement that showed ,25 cm (10") is just an example how that can be done for anyone attempting something like that in the future. Notice that the riser of that stair is set at a slight angle?
I would like them to do that angled riser and obtain a 10" thread, but I am helping these people design this home from the US where I am now, and I am not sure if I can explain the angled riser concept to them via email. I am afraid if I tried I would only confuse them.
I hope I did not confuse more, :)
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Re: Footings, Columns,Beams, and Floor slabs

Postby BKKBILL » Sun Aug 19, 2012 9:08 pm

There really is no reason it can’t be done as you suggest. When they pour the stairs the measurements won’t even be close to the drawing seems everything is adjusted when tiling takes place. Well one can hope. :mrgreen:
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Re: Footings, Columns,Beams, and Floor slabs

Postby geordie » Mon Aug 20, 2012 10:50 am

BKKBILL wrote:There really is no reason it can’t be done as you suggest. When they pour the stairs the measurements won’t even be close to the drawing seems everything is adjusted when tiling takes place. Well one can hope. :mrgreen:


so very true the builder will look at the drawing as "a picture" and ajust everything to suit :lol: suit him that is if its dificult or problematical he will tell you freind "change" "cannot" - thats the explanation sorted :mrgreen:
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