Trench fill level too high

[paulweller84]

Hi all,

I've just finished my foundations and despite making multiple calculations, the confusion of trying to make a block and beam floor meet an existing floor level has somehow left me with a concrete level 360mm below the bottom of the beams instead of 450mm. The plan was two rows of blocks below the beams but now I assume blocks will need to be cut? Is there a way that existing foundation blocks can be arranged to make 360mm without cuts? Diagram attached to show details.

Paul

 

[noseall]

Hi all,

I've just finished my foundations and despite making multiple calculations, the confusion of trying to make a block and beam floor meet an existing floor level has somehow left me with a concrete level 360mm below the bottom of the beams instead of 450mm. The plan was two rows of blocks below the beams but now I assume blocks will need to be cut? Is there a way that existing foundation blocks can be arranged to make 360mm without cuts? Diagram attached to show details.

Paul

You could easily do it with 5 course of bricks tight bedded. Bit of a pig with blocks though. 360mm less one course of blocks leaves you with a horrible number -135mm. It's neither here nor there in terms of block course efficiency.

 

[paulweller84]

You could easily do it with 5 course of bricks tight bedded. Bit of a pig with blocks though.

and this is no issue? I assumed it had to be blocks as that’s what is normally used.

 

[noseall]

Your FFL doesn't make any sense i.e. finishing mid brick...? There is inadequate allowance for screed and insulation, unless you intend cheating on the insulation?

 

[stuart45]

and this is no issue? I assumed it had to be blocks as that’s what is normally used.

Bricks are not a problem. Have you already got the blocks?

 

[paulweller84]

Bricks are not a problem. Have you already got the blocks?

No not got anything yet. I assume I’ll need some pretty strong bricks to support a concrete floor. Also, could it would work to do a row of foundation blocks with 2 rows of brick on top, with very thin joints?

 

[stuart45]

Also, could it would work to do a row of foundation blocks with 2 rows of brick on top, with very thin joints?

I would go for 5 brick courses. Trying to lose that much in 2 courses of brickwork would be really difficult.

 

[paulweller84]

Your FFL doesn't make any sense i.e. finishing mid brick...? There is inadequate allowance for screed and insulation, unless you intend cheating on the insulation?

Thats just matching the floor level of the existing property. The floor will continue from the existing lounge into a new dining room/kitchen. The floor level finishes mid brick. I didn’t realise that wasn’t normal.

The insulation is 75mm with 22mm board on top. There will be self levelling compound on that and vinyl click floor

 

[noseall]

The floor level finishes mid brick

Your DPC will need to finish on a brick course.

The insulation is 75mm with 22mm board on top. There will be self levelling compound on that and vinyl click floor

Don't lay floor levelling compound onto chipboard. No need in any case.​

 

[paulweller84]

Don't lay floor levelling compound onto chipboard. No need in any case.

Forgot to mention there’s underfloor heating mat. The compound goes on top of that

 

[stuart45]

No not got anything yet. I assume I’ll need some pretty strong bricks to support a concrete floor.

You could use concrete commons where they are not seen. If you get some frogged ones it could help for the first course if the footing concrete is a bit high in places as they are easier to crop than solid ones.

 

[^woody^]

The floor is screeded, just drop the beams to work bricks or blocks or concrete bricks, lego bricks, casio calculators whatever, and then make up the FFL with screed or insulation. No need for NASA on this one.

 

[paulweller84]

just drop the beams

You mean lower the floor structure completely? That would mean excavating a metric sh*t ton of earth to allow the 150mm air gap below. Not an option unfortunately.

 

[^woody^]

What about the air gap between the beams?

 

[paulweller84]

What about the air gap between the beams?

Well that will be there for sure. But building control have stated 150mm clear below the beams