Will this floor patch give way ?

[Spinny]

Patching in floor at a doorway. All prepped and now the flooring guy says it won't be strong enough. Was using a strip of 20mm thick XPS backer board. Advice please - is he right or wrong ?

See sketch.

 

Backer board strip 200mm wide supported on one side on celcon blocks 100mm wide, and on other side by 30mm XPS resin bonded to blockwork. The XPS backer board is to have levelling compound applied over to about 15-18mm thick.

 

Flooring guy says it won't pass the stilhetto test, and the XPS must be replaced with solid board ?

 

Flooring will be LVT.

 

[Mr Punter]

Threshold details are a right pain.  I guess he is concerned that there may be cracking between the different substrates.  Who knows if he is right?  I guess you either do as he asks if he is willing to take responsibility in the event of it being defective or you leave it as is and you take the responsibility.

 

And maybe stop wearing stilettos around the house.

Edited 10 hours ago by Mr Punter

[Nickfromwales]

The XPS board goes in the cavity, vertically, bonded to the inside edge of the outer leaf of block.

 

Then you remove the inner leaf for the full width of the opening.

 

Fix a piece of 30mm PIR, or more slices of XPS, as an insulation upstand. 
 

Then DPC, and then fill with a strong concrete mix with 10mm aggregate. 
 

Delete the cavity!

[JohnMo]

Sounds pretty weak. If you want a stronger version but also insulated use Compacfoam. Make it deeper than 20mm by doing a double layer glued and screwed together.

[Spinny]

I thought my test piece was fine - see photo with a wider span than needed and no leveller...

 

I thought people used this stuff under screeded underfloor heating pipes on suspended floors ??

 

I am thinking that with 15mm plus cementitious leveller on top it would have good compression strength and seems nice and stiff compared to thinner backer board. The stilhetto test seems pretty extreme (I havn't seen a man in stilhettos since a trip to Key West).

 

I could stick 10mm backer board to the bottom of a piece of 12mm ply I suppose ?

 

Never seen or used compacfoam so not sure what it is really like ? Polystyrene bears loads but not point loads.

 

Come on England ⚽