Internal GFL and DPM in cavity

[LSB]

Right, a question about the DPC  in the internal cavity wall and the DPM under the internal floor level.

 

We have the internal cavity wall built to what we planned to be the DPC level in the wall

But, due to the build up of the floor being suspended on the foundation by the time we put the insulation and screed on top of the slab the GFL will be higher than the DPM

 

Please note this is not to scale, just to show what I mean, the external FFL is 150 below the DPM rather than a whole block.

 

 

So, we need to have DPC in the wall with the sheet under the insulation, I know we have to have some insulation running beside the screed as well, but just not shown here.

The plan was to place the DPC in the wall with a 'skirt' to be joined to the DPM sheet, but is it okay to have some of the insulation and the screed on the internal wall above the DPC

Or, should we put the wall DPM a block higher so it is all wrapped, we have full fill insulation of 150mm

This would mean that the external and internal DPM would be at a different level.

 

FYI, the only thing in situ yet is the suspended floor and the internal wall to planned DPC.  

The brickie is starting on the external wall today.

 

One of the things  we need to do with these levels is conside the level access for doors, but we plan on doing this will a gently sloping ramp and French drains.

 

TIA

 

[nod]

59 minutes ago, LSB said:

Right, a question about the DPC  in the internal cavity wall and the DPM under the internal floor level.

 

We have the internal cavity wall built to what we planned to be the DPC level in the wall

But, due to the build up of the floor being suspended on the foundation by the time we put the insulation and screed on top of the slab the GFL will be higher than the DPM

 

Please note this is not to scale, just to show what I mean, the external FFL is 150 below the DPM rather than a whole block.

 

 

So, we need to have DPC in the wall with the sheet under the insulation, I know we have to have some insulation running beside the screed as well, but just not shown here.

The plan was to place the DPC in the wall with a 'skirt' to be joined to the DPM sheet, but is it okay to have some of the insulation and the screed on the internal wall above the DPC

Or, should we put the wall DPM a block higher so it is all wrapped, we have full fill insulation of 150mm

This would mean that the external and internal DPM would be at a different level.

 

FYI, the only thing in situ yet is the suspended floor and the internal wall to planned DPC.  

The brickie is starting on the external wall today.

 

One of the things  we need to do with these levels is conside the level access for doors, but we plan on doing this will a gently sloping ramp and French drains.

 

TIA

 

It won’t make any difference 

The membrane under the insulation should be joined to your dpc (blue)

Then you would put a 100 mill upstand on the top of your insulation Usually 25 mill foil backed sheet ripped into 100 mil strips ( red)