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Extensions Question

How to finish block and beam floor to finish with existing floor?

The block and beam floor has been installed and the extension is complete. However the B&B needed to be 150mm lower than existing floor to allow for insulation 75mm and 75mm screed, However the floor is only 90mm lower and there is no way to lower it now. What would be my best option to finish the floor to keep the same floor height?

Thanks in advance.

I think I would go with the 70 / 75 mm insulation and then lay the green T&G boards on top - just lay on top of insulation or batten?

5 Answers

Best Answer

I would go for the thicker insulation with a 18mm T&G green wedi board,
Glue all joints and have floating floor.
In response to your last post, yes just lay your boards on insulation, as said, glue all joints, leave expansion gap around edges.

Answered 25th Feb 2011


Member since 29 Oct 2008

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you have two options, 1, reduce the thickness of insulation and keep screed at 75mm (this would have to be agreed with building control) 2, use a floating floor system where you keep insulation at 75mm an fix 15mm ply on top.

Answered 25th Feb 2011

NWT Northwest Tiling & Building

Member since 13 Nov 2007

Yes i would go for, either 75mm kingspan insulation & 18mm T&G green chipboard on top, or 70mm insulation & 22mm T&G green chipboard on top & of course all joints glued

Answered 27th Feb 2011

Ceka Construction Limited

Member since 14 May 2008

30mm insulation 60mm screed

Answered 25th Feb 2011


Member since 7 Jun 2008

hi you have made a massive mistake or your builders have their is no way you can go with building regulations so if the floor cant be taken down to lower level then you have only limited options either disregard any floor insulation and go for a 90 mm screed or use a thinner insulation and make up the deiff with new floor screed .or use a false floor and use 3x2 timbers and 22mm or 18mm chipboard and insulate beteeen the timbers making sure you lay a membrene down first other than that ask the building control how best to resolve problem

Answered 25th Feb 2011

Finebuild Builders

Member since 26 Feb 2009

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