Block and beam floor question

[davphi338]

Hi,

I have just had a block and beam floor laid for my new extension, there is a 100mm gap between the floor and the external brickwork i.e the floor does not go all the way to the external brickwork. I don't see this as a problem where I am having internal blockwork but i am also having folding sliding doors. I presume the frame sits on the external brickwork meaning there will be a 100mm gap between the framework of doors and where the internal floor starts.

what n ormally happens in this situation. Is the gap filled with concrete to bridge the hole?

 

[freddiemercurystwin]

There shouldn't be any gaps eg http://images.google.co.uk/imgres?i...s?q=beam+and+block+floor&gbv=2&hl=en&safe=off

 

[davphi338]

The link shows the beams sitting on the internal block work, as with my floor. My point is, what happens when I have sliding doors so there is no internal blockwork and there is going to be a gap of 100mm where the insulation normally would sit.

 

[freddiemercurystwin]

Oh I see, the cill needs to bridge the gap something like this: http://www.ascinfo.co.uk/9/resourcefile/33/13/63/default331363_9.html although if I was drawing it I'd show insulation in the cavity and I'd also insert a piece of cavity wall insulation horizontally between the outer skin and the edge of the beam and block floor as you've got a 100mm gap to fill. The cill needs to be the component taking all the force when you step on it so would need to be a good deal wider than the block as you've got a dirty great gap to fill. You could fill the gap with concrete provided the floor insulation meets the back of the cill (I assume your insulation is over the top of the beam & block floor) although IMO that'd be a bit lazy. But then I'm a belt n braces designer!

 

[davphi338]

Had a word with the builders this morning and they say there has to be a gap between the internal and external blockwork to prevent damp bridging. They say the insulation is laid over the floor and then screeded which is sufficient support over the gap.