Concrete slab poored for garden room office

[Ttw]

I've had a concrete slab poored today and just found out from the contractor that he did the following. 

 

100mm 40mm to dust compacted with a a dpm (visqueen thick guage) layed straight on top lapping up onto the inner skin of blockwork. 

 

HE DID NOT USE A BLINDING OF SAND

 

instead he layed another layer of dmp on top of the insulation but not lapping the wall. 

 

Then he poored the 100mm concrete slab. 

 

In short 

 

Crusher run compacted 

Dpm lapping inner skin

Insulation 

Dpm

Concrete

 

Am i likely to suffer damp issues? Fortunately its quite dry round with sandy conditions and great drainage. 

 

Sorry to be long winded in my description. 

Edited June 9, 2020 by Ttw
More information

[Russell griffiths]

NO. 

 

[Ttw]

On 09/06/2020 at 21:27, Russell griffiths said:

NO. 

 

Thanks Russell, I thought not but pretty sure the visqueen dpm would be pierced by the 40mm crushed stone. The second dpm doesn't run up the 25mm insulation upstand but hopefully it will keep any damp at bay. 

[PeterW]

13 minutes ago, Ttw said:

Thanks Russell, I thought not but pretty sure the visqueen dpm would be pierced by the 40mm crushed stone. The second dpm doesn't run up the 25mm insulation upstand but hopefully it will keep any damp at bay. 

 

You also have an insulation layer that is pretty impervious to damp. Unless you have a very high water table, then you will not have a problem

[Ttw]

On 12/06/2020 at 09:03, PeterW said:

 

You also have an insulation layer that is pretty impervious to damp. Unless you have a very high water table, then you will not have a problem

Much appreciate your comment and yes it totally makes sense that damp won't be an issue. The next issue is finishing the build and keeping the overall height under 2500mm... I guess that's another topic