Ideas for floor structure

[deuce22]

Hi.

 

I have attached an image of what the structural engineer has come up with for the design of the floor for both the first and second floor. I'm racking my brain to try and come up with another way without having to use all that steel.

Any other ideas?

 

Thanks.

 

Edited November 13, 2020 by deuce22

[Mr Punter]

Why not use both sides of the steels?  Is downstairs completely open plan, so not even somewhere for a column or 2?

 

For all this you are still left with joists over 4m long.

[nod]

You could add some internal solid walls Which would allow you to get rid of some of the steel 

Unless you wanting most of the GF to be open plan 

Edited November 13, 2020 by nod

[markc]

I am a little confused why they are using UC`s as beams? 

[deuce22]

I'm not 100% sure, but I'm guessing he's chosen 203mm steels, so that it doesn't create a bulkhead and because they're only 203mm, they're not strong enough on their own, that's why there's 2 together.

 

The ground floor is not open plan. I have attached an image of the layout. Would I have to dig out foundations for the walls to be supporting or could they just rest on top of a 150mm slab? Would 4x2 walls, strengthened with OSB be strong enough to take the weight of the floor joists above?

 

Why do you point out that they are still 4m long joists? I've just fitted 9x3 floor joists to my garage, which are just over 5m and they are fine. What length joists would you want to be using?

 

What would you use instead of UC beams?

 

Thanks. 

[Faz]

I would have thought for the ground floor you would build sleeper walls on 450mm footings where required which would then allow a standard beam and block floor solution - must be cheaper than going for steels.

[markc]

UC is Universal Column, they have a thick web to resist twisting and compressive loads and this makes them heavier for the given section.

UB Universal Beams are designed for horizontal applications and have a much thinner web meaning they can be much lighter, less sag under their own weight and therefore support greater loads for the same depth of beam.

[Gus Potter]

Hi Duece22

 

It would be worth posting a loft plan. I'm wondering why the steels are in tandem?

 

For the self builder who is doing a one off project then maybe it's worth looking at the bigger picture. You may on first appearance have say an 20 -30% extra steel weight. Take a self build rate for beams / UC sections with not a lot of holes, welding (shot blasted and primed) at £ 3000.00 per tonne delivered (Westen Isles excluded!) to be on the safe side. While the steel may seem heavy they can be simple to install.  If in a rural area your local farmer will come with a telehandler and lift them in for you. If you are DIY hands on then you can lift them with a chain hoist, or just lift one end  a little bit at a time .. story for another day.

 

UCs (often called column sections) are mainly intended to carry vertical loads, thus they are more squat.. they have a thicker web than a UB ..universal beam that is mainly intended to carry bending forces.. like a floor joist. However, you often see them used where you need to try and keep the floor thickness down say.  Yes, you have a heavier steel section which costs a bit more as it is heavier.

 

They key here is to not make it too complex. Yes, you may save on steel weight if you look to value engineer just the steel but as you make it more complex you reduce you options on the amount of contractors that are able to take the job on, or they add an uplift which more than offsets the steel savings.

 

Duece, depending on your loft layout you could introduce a steel newal post at the stairs.. but the stairs look like a key feature... almost free standing and making a statement.  Also that post and other load bearing walls would need foundations. If you take skilled labour at £ 900.00 to 1100.00 a week you can see how a contactor who may be pricing will just say... This is the 10th job I have priced that this week, I'll add a "couple of grand" to cover me.. as the beams now are slim, fancy connections and so on. I know it seems rough but go for simple stupid.

 

You could look at designing the roof / loft so that you hang the structure below from it. This is technique used often.. but it adds complexity and introduces buildability issues that your local builder may be less familiar with.

 

All the best.

 

 

 

 

[deuce22]

Thanks for all your help. I've got some things to think about.