Why aren't hollow flush (to ceiling) blocks used in the UK for beam & block floors?

[Boyblue]

The hollow flush blocks seem to tick a lot of boxes.  It has the density and strength, eliminates the need for slip bricks, and it leaves you with a flush ceiling.  So what am I missing here?  The only disadvantage I see is that the profile looks like it will take significantly more screed, but the offset of a flush ceiling seems like a fair tradeoff presuming you're able to apply plaster .

Edited January 30 by Boyblue

[Canski]

https://www.litecast.co.uk/products/robust-upper-floors/

 

 

[JohnMo]

7 minutes ago, Boyblue said:

leaves you with a flush ceiling

What happens with wiring for lights and plumbing etc?

 

Really see zero advantage to block and beam for anything especially for first or mid floors.

[Boyblue]

23 minutes ago, Canski said:

https://www.litecast.co.uk/products/robust-upper-floors/

 

 

Yes, the light Cast does leave a flush ceiling, but it's a 100mm block and requires a 50mm pour just to bring it flush with the beams.

[Boyblue]

25 minutes ago, JohnMo said:

What happens with wiring for lights and plumbing etc?

 

Really see zero advantage to block and beam for anything especially for first or mid floors.

Electrical would go as it does now in the screed.  Plumbing of course would go below, so a second ceiling would be needed in rooms with drain pipes.  It may be compettive with first floor poured concrete slabs, but I catch your drift.

[Boyblue]

The answer did come to me though.  The genius of what I call the UK system, is the flexibility of being able to use the narrow side to basically double the strength of a section of floor.  You also have the wide beam which aids in flexibility.  And besides unless you'd be applying a cementitious plaster, you could be asking for trouble skimming all those different surfaces, because monolithic above doesn't mean monolithic below.

[Conor]

11 hours ago, Boyblue said:

The answer did come to me though.  The genius of what I call the UK system, is the flexibility of being able to use the narrow side to basically double the strength of a section of floor.  You also have the wide beam which aids in flexibility.  And besides unless you'd be applying a cementitious plaster, you could be asking for trouble skimming all those different surfaces, because monolithic above doesn't mean monolithic below.

In Europe you'd always be adding a suspended ceiling underneath, otherwise you wouldn't be compliant with a raft of regulations. Above, also normal to grout, then insulation layer then screed. So flushness of top or bottom not really relevant. Ours were so uneven, we opted for liquid insulating screed, rather than attempting to level with sand and lay down boards. You have the curve of the beams to contend with anyway. You also have the human factor, the neatness of installation.

 

We used precast hollow concrete planks for our build, 1200mm wide, 5m long. These were smooth top and bottom, interlocked together, in theory leaving a narrow beveled grove to grout in. In reality, beams were slightly different shape, the supporting walls weren't perfect, some beams were slightly the wrong size. A lot had to be persuaded in to position. Result being a fair bit of unevenness, top and bottom, and lots of grouting needed on top. So, do not expect a perfect finish by any means. Esp if this method is unfamiliar to those working with it.

 

 

 

Edited January 31 by Conor

[Boyblue]

55 minutes ago, Conor said:

In Europe you'd always be adding a suspended ceiling underneath, otherwise you wouldn't be compliant with a raft of regulations. Above, also normal to grout, then insulation layer then screed. So flushness of top or bottom not really relevant. Ours were so uneven, we opted for liquid insulating screed, rather than attempting to level with sand and lay down boards. You have the curve of the beams to contend with anyway. You also have the human factor, the neatness of installation.

 

We used precast hollow concrete planks for our build, 1200mm wide, 5m long. These were smooth top and bottom, interlocked together, in theory leaving a narrow beveled grove to grout in. In reality, beams were slightly different shape, the supporting walls weren't perfect, some beams were slightly the wrong size. A lot had to be persuaded in to position. Result being a fair bit of unevenness, top and bottom, and lots of grouting needed on top. So, do not expect a perfect finish by any means. Esp if this method is unfamiliar to those working with it.

 

 

 

Thank you so much, I see all the videos of neat installations and might have been dejected.  I realize they've been doing this for years.

 

BTW which beam did you use, I feel like that kinda I shaped one may be the more problamatic of the two basic shapes.

[G and J]

14 hours ago, Canski said:

https://www.litecast.co.uk/products/robust-upper-floors/

 

 

Hang on.  I just watched the vid displayed on the above link.  The blocks are shaped so they sit 50mm down from the top of the beam.  Couldn’t I use these on a downstairs bnb floor and fill the 50mm with insulation?

[Canski]

26 minutes ago, G and J said:

Hang on.  I just watched the vid displayed on the above link.  The blocks are shaped so they sit 50mm down from the top of the beam.  Couldn’t I use these on a downstairs bnb floor and fill the 50mm with insulation?

Rather than re invent the wheel why not stick to tried and tested routes. I'm pretty sure that the 50 mm of concrete is a structural topping. There are other insulated beam and block systems on the same website. I used these on my 2 builds without any problems. Well that was until Stevie Wonder arrived to pump the structural topping. 

 

 

[Conor]

3 hours ago, Boyblue said:

Thank you so much, I see all the videos of neat installations and might have been dejected.  I realize they've been doing this for years.

 

BTW which beam did you use, I feel like that kinda I shaped one may be the more problamatic of the two basic shapes.

Ours was a locally made 150mm thick hollowcore tensioned slab, 1200mm width, length 4.5m. 115m2 installed in a couple hours, directly off the lorries. 

 

You carry a lot of extra risk using any system that doesn't have local expertise.

[G and J]

1 hour ago, Canski said:

Rather than re invent the wheel why not stick to tried and tested routes. I'm pretty sure that the 50 mm of concrete is a structural topping. There are other insulated beam and block systems on the same website. I used these on my 2 builds without any problems. Well that was until Stevie Wonder arrived to pump the structural topping. 

 

 

I was quite keen on using an insulated BnB floor till we thought through the process of building and the need to temporarily board out the ground floor, plus the idea of polystyrene sitting there accessible from the void didn’t sound as rodent proof as I’d like.  
 

Thinking about it one would have to board out anyway as it would be a huge trip hazard, the beams 50mm above the blocks.  Another stupid idea on the fire….