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Extensions

New extension floor level help

Anonymous user 23/02/2024 - 3.24 PM

Hi all, im in the process of building a side extension onto my existing living room, I'll then be inserting an rsj on the load bearing wall of the house to create 1 big room.. I'm planning on putting in a solid concrete floor but the calculations aren't working out once I've added up the hard-core insulation ect. From the top of the house foundations to the existing living room floor is 480mm. My building control guy said I need 225 hard-core. 50mm sand binding.. Membrane 75mm celotex Membrane 100mm concrete slab That should take me 30mm below the existing living room floor. Them measurements add up to 450 and that would only leave me with 30mm for screed so I can bring the level up to the existing flooring.. Is 30mm screed too thin? Can I bring the hard-core depth down from 225 to 205 so I can apply the screed thicker (50mm) Any other suggestions? Thanks Adam

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4 Answers

Hartwell Projects Ltd

Rating: 5 out of 5
Poole
Hi Adam I’m unsure why Building control Are asking for more than 150mm of compacted hardcore / rejects as this would normally be adequate in normal ground conditions ! However if this depth has been stipulated by an engineer you could simply excavate down to the required depth below the top of your foundation as the concrete here should be at least 150mm thick so would not be undermined ! Best regards Hartwell Projects ltd
Answered27 June 2019
1

SPS Building and Joinery Services

No reviews yet

Rotherham
Thats a lot of binding sand reduce it 20mm or mix your screed with SBR compound you can screed as low as 25mm using this rubberoid compound to bind the screed together !
Answered27 June 2019
0

c&j developments

Rating: 4.8 out of 5
Birmingham
Yes. Hardcore is only filling to make up levels. Lessen hardcore increase concrete /screed.
Answered27 June 2019
0

Right Price Builders

Rating: 5 out of 5
Plymouth
You must dig deeper and install a honeycomb sleeper wall to accomodate a block and beam concrete floor. 50mm fibre screed is the absolute minimum or else the screed will fail. If employing underfloor heating then 60mm is the minimum.
Answered27 June 2019
0