[broden]

alright many of you have seen that i'm playing around with the design of our future home..and i've realized one of the things i don't know much about is the thickness of the floors in a multi-story building .. i mean from the ceiling below to the floor above.. 18 inches, 2 feet? what's normal? .. what ,if it could be said ,would be optimal?


and while i'm asking .. anyone out there know the "normal" measurements of a spiral staircase.. i like the wrought iron kind .. just width and depth .. so i could place it in a room or at least a square that would symbolize them ... just a nice normal spiral stair case not a huge one

[SkyMan]

As for ceiling to floor thickness, I was just looking at this last night. The construction I saw was very open and lent itself to such inspection. The construction I saw had normal steel reinforced concrete posts but instead of the being used for the beams, it had a steel truss structure with the longest span about 10 meters. I'm not sure if a longer span is acceptable in such construction though. On top of the truss system was corrugated steel and then a layer of about 5 inches of concrete I would assume had steel reinforcement. The upper floor was 50-60 meters square and has no cracks I noticed.

As for the spiral staircase it's kind of up to you. The smaller the diameter the quicker the stairs must rise because if they don't rise fast enough they will come around and hit you in the head so the rise has to be high enough to get above your head. Also realize with spirals that the smaller the diameter, the more you are pushed to the outside of the stairs going up or down because the inner part of the steps don't have enough run to stand on them. Small spirals are difficult to move things up and down and forget furniture. I would suggest trying to visit places with spirals to see what you like and measure them. I saw a small one in an wrought iron works but it was only the first few steps so I don't know if it would rise quick enough to give me enough headroom to use. Another thing you could do is design what you want in a CAD program so you could see the headroom you would get with a given rise and run and the draw that out on poster paper life sized in 2D so you could see what it's like stepping on those steps. You might also be able to find some designs online that give you rise run and headroom.

[broden]

SkyMan, on 08 February 2010 - 06:10 PM, said:

As for ceiling to floor thickness, I was just looking at this last night. The construction I saw was very open and lent itself to such inspection. The construction I saw had normal steel reinforced concrete posts but instead of the being used for the beams, it had a steel truss structure with the longest span about 10 meters. I'm not sure if a longer span is acceptable in such construction though. On top of the truss system was corrugated steel and then a layer of about 5 inches of concrete I would assume had steel reinforcement. The upper floor was 50-60 meters square and has no cracks I noticed.

hey thanks for the info


that sounds pretty good ..so what do you think the total thickness was?

as far as the stairs .. yeah i need to just go look at some ..i'll be looking some up online too (or trying to) just to get a better grasp .. i've seen the kind i like before of course but never had need or want to get a measurement of any kind ... i won't need to be moving furniture up and down them so that's not a concern ..well other then a folding chair a folding tv dinner type table a telescope perhaps stuff like that small stuff


ha well that was easier then i thought now that i had a moment to look .. something like this .. seems they at least this one company has 3 basic sizes .. 5 feet 5.5 feet or 6 feet diameter .. depending on how we finish the room it's put in the finish could be like this .. but i'd be happy with 100% black wrought iron

this is off of a staircase company who's website i just went to at random

This post has been edited by broden: 09 February 2010 - 08:36 AM

[SkyMan]

broden, on 08 February 2010 - 07:28 PM, said:

that sounds pretty good ..so what do you think the total thickness was?

Sorry, forgot to mention the trusses were about a foot thick so the whole floor was about 18 inches.

That's a very nice looking staircase and the rise isn't too quick while the steps have a decent amount of run around the outside. I'm trying to avoid stairs myself but I think my design will require some as half my lot slopes down so I'll have kind of a 2 level effect with the possibility of a pool on the third level.

[Balay]

Are you planning on pouring a solid concrete deck with reinforced re bar ?

If so .. I have to ask why ? That is going to cost a lot in material and labor. In addition to adding to bigger columns and beams. The weight of a poured deck is way too heavy for a residential building.

Why not just use galvanized steel 2x4 C purlins, with a distance of 12 inches center to center, Add Pieces of 2x4, installed between joists at the center of their span. Bridging should be installed at no more that 7' apart, between each support or other bridging. Tie it all together with with 3/4 inch marine plywood treated with anti anay.

There for the distance of ceiling below to the floor above is based on what you plan to put in between. Will you be using air ducts, plumbing and electrical.

What you should be more concerned is the size of the truss, columns and beams, based on the struture you plan to build.

Spiral code requirements are:

Maximum rise: 9-1/2" (this is higher than the maximum rise for a straight stair because you have to go down a spiral more steeply to gain sufficient headroom under the top landing).

Minimum headroom: 78".

Minimum horizontal width of tread: 7-1/2" at a point 12" out from the center column.

Minimum width of clear passageway: 26" from the inside of the handrail to the outside of the center column.

Baluster spacing: most codes require a space of no more than 4" between balusters.

Minimum opening between treads: no more than 4".

[broden]

SkyMan, on 08 February 2010 - 07:16 PM, said:

broden, on 08 February 2010 - 07:28 PM, said:

that sounds pretty good ..so what do you think the total thickness was?

Sorry, forgot to mention the trusses were about a foot thick so the whole floor was about 18 inches.

That's a very nice looking staircase and the rise isn't too quick while the steps have a decent amount of run around the outside. I'm trying to avoid stairs myself but I think my design will require some as half my lot slopes down so I'll have kind of a 2 level effect with the possibility of a pool on the third level.

18 .. that's what i was looking for .. thanks again

i could have a pool .. where my second floor patio will be if i want to do with out a living room haha

Balay
not sure which way i'm going to go yet as far as the physical nature goes .. just conceptualizing, more or less, for now

but i can say i don't care for central air .. just never have i'd rather have window units or something very similar .. so no air ducts

the spiral will likely be in one corner of our bedroom ,going to the third floor .. or in a separated hallway off the bedroom that would also contain the normal stairs going between the first and second floor

[fanboat]

Google Iron shop for the stairs...5 foot 6 inches...code in the states.

my ceiling is pour in place 4 inch reinforced concrete...here they build poured in place beam and columns with #4 rebar reenforcements.

the span would be under 16 feet for this thickness

Robert 51...has the best house I have seen....talk to him!

[broden]

fanboat, on 08 February 2010 - 10:28 PM, said:

Google Iron shop for the stairs...5 foot 6 inches...code in the states.

my ceiling is pour in place 4 inch reinforced concrete...here they build poured in place beam and columns with #4 rebar reenforcements.

the span would be under 16 feet for this thickness

Robert 51...has the best house I have seen....talk to him!

thanks for the measurements
i know i'm going to have to use beams/trusses so i know that's going to up the thickness... but not looking to minimize or maximize it for now just looking for numbers .. so i think 18" is a good point to start at

oh and thanks for the confirmation on the spiral measurements .. that's wht i found too .. but i didn't know it was code .. just the measurement the place i looked at offered .. so thanks for that info too

yeah robert is a wealth of info .. and yeah he has an awesome place no doubt

[AmpingKanunay]

Broden, 18" thick floors is for a high rise building, which also gives it literal strength for example in high winds. What you are planning would not need such a massive structure. A structural engineer can crunch the numbers for you.

[philuk]

I have to agree with jesseB 18 inches is way over the top, and would be far to heavy for conventional walls to hold up,
the weight would simply crush a 9 inch block wall

The floors in my house here in the UK built from timber joists and floor boards is 9 inches from plasterboard to the top of the floor boards,
and is only this thick as the 4 inch block walls upstairs are built straight off the floorboards,

A reinforced concrete floor would not tneed to be this thick,
Normally the whole house would only stand on a 9 inch reinfoced concrete slab,

[broden]

philuk, on 09 February 2010 - 11:32 AM, said:

I have to agree with jesseB 18 inches is way over the top, and would be far to heavy for conventional walls to hold up,
the weight would simply crush a 9 inch block wall

The floors in my house here in the UK built from timber joists and floor boards is 9 inches from plasterboard to the top of the floor boards,
and is only this thick as the 4 inch block walls upstairs are built straight off the floorboards,

A reinforced concrete floor would not tneed to be this thick,
Normally the whole house would only stand on a 9 inch reinfoced concrete slab,

thanks for the added confirmation man

[sperry]

broden, on 10 February 2010 - 05:58 AM, said:

philuk, on 09 February 2010 - 11:32 AM, said:

I have to agree with jesseB 18 inches is way over the top, and would be far to heavy for conventional walls to hold up,
the weight would simply crush a 9 inch block wall

The floors in my house here in the UK built from timber joists and floor boards is 9 inches from plasterboard to the top of the floor boards,
and is only this thick as the 4 inch block walls upstairs are built straight off the floorboards,

A reinforced concrete floor would not tneed to be this thick,
Normally the whole house would only stand on a 9 inch reinfoced concrete slab,

thanks for the added confirmation man

Well I dont know what phil construction standards are but here in my neck of the wooods:

a concrete floor will be made of hollow concrete block, laid between small concrete beams and shaped as to give flat ceiling underneath which can and normally would be plastered on directly. You then put a steel grill on the top of the concrete, and run 2*2 reinforcement bars in a continuous chain around the outside.

the height is always 20 cms (about 8 inches), one brick height in a normal house, which is put on 20 cm wide hollow block wall. you can tell it is 20 cm cos a lot of builders put in a single course of hollow block around the outside to hold the concrete in while it sets. this also helps to stop exterior cracks in the finish around the floor.

once the concrete is down you would typically have about 7cm of screed on the top, before the tiles or other finish.
7cm is not a huge amount if you have water pipes and electrical conduit to be buried under the screed

sorry if my terminology is all wrong, but i dont know the english terms for what im talking about, (although i do know what im talking about)

[SkyMan]

JesseB, on 09 February 2010 - 06:30 AM, said:

Broden, 18" thick floors is for a high rise building, which also gives it literal strength for example in high winds. What you are planning would not need such a massive structure. A structural engineer can crunch the numbers for you.

I wasn't talking about 18 inches of concrete, I said that it was 5 inches of concrete held up by steel trusses about a foot thick. This wasn't a high rise but the second floor (basically a party deck) of a restaurant I know.
Steel posts go up frpm there to support the steel framework which for the roof.

[broden]

i really appreciate all the input everyone

thanks a bunch