Are small height differences between beam and block in floor problematic?

[AFT4B]

We have had to install a beam and block floor throughout the whole house on the ground floor. Despite having spread sand and cement slurry across it, in some areas the blocks sit about 1-2mm lower than the beams. Bearing in mind we have to lay PIR and screed - should I be worried about the insulation not being completely supported underneath?

In areas there is build up from cement/ materials used to do other jobs - which is quite hard to remove. Should I try to remove this or not worry about it?

 

[noseall]

We have had to install a beam and block floor throughout the whole house on the ground floor. Despite having spread sand and cement slurry across it, in some areas the blocks sit about 1-2mm lower than the beams. Bearing in mind we have to lay PIR and screed - should I be worried about the insulation not being completely supported underneath?

Minor discrepancies are not an issue no. Something as simple as building sand scattered about and packed in the hollows is all you need if you are concerned How much room do you have left for insulation and screed?

 

[AFT4B]

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[AFT4B]

Minor discrepancies are not an issue no. Something as simple as building sand scattered about and packed in the hollows is all you need if you are concerned How much room do you have left for insulation and screed?

Thanks @noseall

It's about 140mm to damp for insulation and liquid screed. Not ideal as I wanted thicker insulation but having to retro fit the floor into the existing house has meant we've just had to make things work.

I feel like I'm over thinking it but if the PIR was 100mm would having these voids cause 40mm screed to crack?

Also, does the screed have to be up to/ below DPC or can it be, say 50mm which would be about 10mm above DPC. Given DPM is to go down and if we "over engineer" on the thickness of the DPM and seal all the joints really well then there shouldn't be any bridging - right?

 

[phatboy]

If you have the odd block 2-3mm low, anything above 50mm PIR isn't going to sink into it really. If you have mortar on the blocks, a hand grinding block is very good, but if its only slight it will just indent the insulation.

100mm floor insulation is likely plenty, unless you have a large exposed perimeter to outdoors. Not a huge amount if heat is lost through the floor.

Our screed is fibre reinforced

 

[cdbe]

Looks like more than a few mm on the first pic. If it was me I'd probably throw a few bags of cheap self levelling compound at it for my own peace of mind.

 

[noseall]

Thanks @noseall

I feel like I'm over thinking it but if the PIR was 100mm would having these voids cause 40mm screed to crack?

40mm for an unbonded s/c screed is not ideal. I'd be thinking 70mm PIR and the rest screed.

Also, does the screed have to be up to/ below DPC or can it be, say 50mm which would be about 10mm above DPC. Given DPM is to go down and if we "over engineer" on the thickness of the DPM and seal all the joints really well then there shouldn't be any bridging - right?

The screed can finish above DPC, no dramas as long as height relevant items are not affected like door casings, fitted items or glazing (toughened rules) etc. Finishing below DPC can be problematic.

 

[noseall]

Looks like more than a few mm on the first pic. If it was me I'd probably throw a few bags of cheap self levelling compound at it for my own peace of mind.

Really no need for that expense or faff.